1. Introduction

Proxmox VE is a platform to run virtual machines and containers. It is based on Debian Linux, and completely open source. For maximum flexibility, we implemented two virtualization technologies - Kernel-based Virtual Machine (KVM) and container-based virtualization (LXC).

One main design goal was to make administration as easy as possible. You can use Proxmox VE on a single node, or assemble a cluster of many nodes. All management tasks can be done using our web-based management interface, and even a novice user can setup and install Proxmox VE within minutes.

Proxmox Software Stack

1.1. Central Management

While many people start with a single node, Proxmox VE can scale out to a large set of clustered nodes. The cluster stack is fully integrated and ships with the default installation.

Unique Multi-Master Design

The integrated web-based management interface gives you a clean overview of all your KVM guests and Linux containers and even of your whole cluster. You can easily manage your VMs and containers, storage or cluster from the GUI. There is no need to install a separate, complex, and pricey management server.

Proxmox Cluster File System (pmxcfs)

Proxmox VE uses the unique Proxmox Cluster file system (pmxcfs), a database-driven file system for storing configuration files. This enables you to store the configuration of thousands of virtual machines. By using corosync, these files are replicated in real time on all cluster nodes. The file system stores all data inside a persistent database on disk, nonetheless, a copy of the data resides in RAM which provides a maximum storage size is 30MB - more than enough for thousands of VMs.

Proxmox VE is the only virtualization platform using this unique cluster file system.

Web-based Management Interface

Proxmox VE is simple to use. Management tasks can be done via the included web based management interface - there is no need to install a separate management tool or any additional management node with huge databases. The multi-master tool allows you to manage your whole cluster from any node of your cluster. The central web-based management - based on the JavaScript Framework (ExtJS) - empowers you to control all functionalities from the GUI and overview history and syslogs of each single node. This includes running backup or restore jobs, live-migration or HA triggered activities.

Command Line

For advanced users who are used to the comfort of the Unix shell or Windows Powershell, Proxmox VE provides a command line interface to manage all the components of your virtual environment. This command line interface has intelligent tab completion and full documentation in the form of UNIX man pages.

REST API

Proxmox VE uses a RESTful API. We choose JSON as primary data format, and the whole API is formally defined using JSON Schema. This enables fast and easy integration for third party management tools like custom hosting environments.

Role-based Administration

You can define granular access for all objects (like VMs, storages, nodes, etc.) by using the role based user- and permission management. This allows you to define privileges and helps you to control access to objects. This concept is also known as access control lists: Each permission specifies a subject (a user or group) and a role (set of privileges) on a specific path.

Authentication Realms

Proxmox VE supports multiple authentication sources like Microsoft Active Directory, LDAP, Linux PAM standard authentication or the built-in Proxmox VE authentication server.

1.2. Flexible Storage

The Proxmox VE storage model is very flexible. Virtual machine images can either be stored on one or several local storages or on shared storage like NFS and on SAN. There are no limits, you may configure as many storage definitions as you like. You can use all storage technologies available for Debian Linux.

One major benefit of storing VMs on shared storage is the ability to live-migrate running machines without any downtime, as all nodes in the cluster have direct access to VM disk images.

We currently support the following Network storage types:

  • LVM Group (network backing with iSCSI targets)

  • iSCSI target

  • NFS Share

  • CIFS Share

  • Ceph RBD

  • Directly use iSCSI LUNs

  • GlusterFS

Local storage types supported are:

  • LVM Group (local backing devices like block devices, FC devices, DRBD, etc.)

  • Directory (storage on existing filesystem)

  • ZFS

1.3. Integrated Backup and Restore

The integrated backup tool (vzdump) creates consistent snapshots of running Containers and KVM guests. It basically creates an archive of the VM or CT data which includes the VM/CT configuration files.

KVM live backup works for all storage types including VM images on NFS, CIFS, iSCSI LUN, Ceph RBD or Sheepdog. The new backup format is optimized for storing VM backups fast and effective (sparse files, out of order data, minimized I/O).

1.4. High Availability Cluster

A multi-node Proxmox VE HA Cluster enables the definition of highly available virtual servers. The Proxmox VE HA Cluster is based on proven Linux HA technologies, providing stable and reliable HA services.

1.5. Flexible Networking

Proxmox VE uses a bridged networking model. All VMs can share one bridge as if virtual network cables from each guest were all plugged into the same switch. For connecting VMs to the outside world, bridges are attached to physical network cards assigned a TCP/IP configuration.

For further flexibility, VLANs (IEEE 802.1q) and network bonding/aggregation are possible. In this way it is possible to build complex, flexible virtual networks for the Proxmox VE hosts, leveraging the full power of the Linux network stack.

1.6. Integrated Firewall

The integrated firewall allows you to filter network packets on any VM or Container interface. Common sets of firewall rules can be grouped into “security groups”.

1.7. Why Open Source

Proxmox VE uses a Linux kernel and is based on the Debian GNU/Linux Distribution. The source code of Proxmox VE is released under the GNU Affero General Public License, version 3. This means that you are free to inspect the source code at any time or contribute to the project yourself.

At Proxmox we are committed to use open source software whenever possible. Using open source software guarantees full access to all functionalities - as well as high security and reliability. We think that everybody should have the right to access the source code of a software to run it, build on it, or submit changes back to the project. Everybody is encouraged to contribute while Proxmox ensures the product always meets professional quality criteria.

Open source software also helps to keep your costs low and makes your core infrastructure independent from a single vendor.

1.8. Your benefit with Proxmox VE

  • Open source software

  • No vendor lock-in

  • Linux kernel

  • Fast installation and easy-to-use

  • Web-based management interface

  • REST API

  • Huge active community

  • Low administration costs and simple deployment

1.9. Getting Help

1.9.1. Proxmox VE Wiki

The primary source of information is the Proxmox VE Wiki. It combines the reference documentation with user contributed content.

1.9.2. Community Support Forum

Proxmox VE itself is fully open source, so we always encourage our users to discuss and share their knowledge using the Proxmox VE Community Forum. The forum is fully moderated by the Proxmox support team, and has a quite large user base around the whole world. Needless to say that such a large forum is a great place to get information.

1.9.3. Mailing Lists

This is a fast way to communicate via email with the Proxmox VE community

The primary communication channel for developers is:

1.9.4. Commercial Support

Proxmox Server Solutions Gmbh also offers commercial Proxmox VE Subscription Service Plans. System Administrators with a standard subscription plan can access a dedicated support portal with guaranteed response time, where Proxmox VE developers help them should an issue appear. Please contact the Proxmox sales team for more information or volume discounts.

1.9.5. Bug Tracker

We also run a public bug tracker at https://bugzilla.proxmox.com. If you ever detect an issue, you can file a bug report there. This makes it easy to track its status, and you will get notified as soon as the problem is fixed.

1.10. Project History

The project started in 2007, followed by a first stable version in 2008. At the time we used OpenVZ for containers, and KVM for virtual machines. The clustering features were limited, and the user interface was simple (server generated web page).

But we quickly developed new features using the Corosync cluster stack, and the introduction of the new Proxmox cluster file system (pmxcfs) was a big step forward, because it completely hides the cluster complexity from the user. Managing a cluster of 16 nodes is as simple as managing a single node.

We also introduced a new REST API, with a complete declarative specification written in JSON-Schema. This enabled other people to integrate Proxmox VE into their infrastructure, and made it easy to provide additional services.

Also, the new REST API made it possible to replace the original user interface with a modern HTML5 application using JavaScript. We also replaced the old Java based VNC console code with noVNC. So you only need a web browser to manage your VMs.

The support for various storage types is another big task. Notably, Proxmox VE was the first distribution to ship ZFS on Linux by default in 2014. Another milestone was the ability to run and manage Ceph storage on the hypervisor nodes. Such setups are extremely cost effective.

When we started we were among the first companies providing commercial support for KVM. The KVM project itself continuously evolved, and is now a widely used hypervisor. New features arrive with each release. We developed the KVM live backup feature, which makes it possible to create snapshot backups on any storage type.

The most notable change with version 4.0 was the move from OpenVZ to LXC. Containers are now deeply integrated, and they can use the same storage and network features as virtual machines.

1.11. Improving the Proxmox VE Documentation

Depending on which issue you want to improve, you can use a variety of communication mediums to reach the developers.

If you notice an error in the current documentation, use the Proxmox bug tracker and propose an alternate text/wording.

If you want to propose new content, it depends on what you want to document:

  • if the content is specific to your setup, a wiki article is the best option. For instance if you want to document specific options for guest systems, like which combination of Qemu drivers work best with a less popular OS, this is a perfect fit for a wiki article.

  • if you think the content is generic enough to be of interest for all users, then you should try to get it into the reference documentation. The reference documentation is written in the easy to use asciidoc document format. Editing the official documentation requires to clone the git repository at git://git.proxmox.com/git/pve-docs.git and then follow the README.adoc document.

Improving the documentation is just as easy as editing a Wikipedia article and is an interesting foray in the development of a large opensource project.

Note If you are interested in working on the Proxmox VE codebase, the Developer Documentation wiki article will show you where to start.

2. Installing Proxmox VE

Proxmox VE is based on Debian and comes with an installation CD-ROM which includes a complete Debian system ("stretch" for version 5.x) as well as all necessary Proxmox VE packages.

The installer just asks you a few questions, then partitions the local disk(s), installs all required packages, and configures the system including a basic network setup. You can get a fully functional system within a few minutes. This is the preferred and recommended installation method.

Alternatively, Proxmox VE can be installed on top of an existing Debian system. This option is only recommended for advanced users since detail knowledge about Proxmox VE is necessary.

2.1. System Requirements

For production servers, high quality server equipment is needed. Keep in mind, if you run 10 Virtual Servers on one machine and you then experience a hardware failure, 10 services are lost. Proxmox VE supports clustering, this means that multiple Proxmox VE installations can be centrally managed thanks to the included cluster functionality.

Proxmox VE can use local storage (DAS), SAN, NAS and also distributed storage (Ceph RBD). For details see chapter storage.

2.1.1. Minimum Requirements, for Evaluation

  • CPU: 64bit (Intel EMT64 or AMD64)

  • Intel VT/AMD-V capable CPU/Mainboard for KVM Full Virtualization support

  • RAM: 1 GB RAM, plus additional RAM used for guests

  • Hard drive

  • One NIC

  • CPU: 64bit (Intel EMT64 or AMD64), Multi core CPU recommended

  • Intel VT/AMD-V capable CPU/Mainboard for KVM Full Virtualization support

  • RAM: 8 GB RAM, plus additional RAM used for guests

  • Hardware RAID with batteries protected write cache (“BBU”) or flash based protection

  • Fast hard drives, best results with 15k rpm SAS, Raid10

  • At least two NICs, depending on the used storage technology you need more

2.1.3. Simple Performance Overview

On an installed Proxmox VE system, you can run the included pveperf script to obtain an overview of the CPU and hard disk performance.

Note this is just a very quick and general benchmark. More detailed tests are recommended, especially regarding the I/O performance of your system.

2.1.4. Supported web browsers for accessing the web interface

To use the web interface you need a modern browser, this includes:

  • Firefox, a release from the current year, or the latest Extended Support Release

  • Chrome, a release from the current year

  • the Microsoft currently supported versions of Internet Explorer (as of 2016, this means IE 11 or IE Edge)

  • the Apple currently supported versions of Safari (as of 2016, this means Safari 9)

If Proxmox VE detects you’re connecting from a mobile device, you will be redirected to a lightweight touch-based UI.

2.2. Using the Proxmox VE Installation CD-ROM

You can download the ISO from http://www.proxmox.com. It includes the following:

  • Complete operating system (Debian Linux, 64-bit)

  • The Proxmox VE installer, which partitions the hard drive(s) with ext4, ext3, xfs or ZFS and installs the operating system.

  • Proxmox VE kernel (Linux) with LXC and KVM support

  • Complete toolset for administering virtual machines, containers and all necessary resources

  • Web based management interface for using the toolset

Note By default, the complete server is used and all existing data is removed.
pve-grub-menu.png

Please insert the installation CD-ROM, then boot from that drive. Immediately afterwards you can choose the following menu options:

Install Proxmox VE

Start normal installation.

Install Proxmox VE (Debug mode)

Start installation in debug mode. It opens a shell console at several installation steps, so that you can debug things if something goes wrong. Please press CTRL-D to exit those debug consoles and continue installation. This option is mostly for developers and not meant for general use.

Rescue Boot

This option allows you to boot an existing installation. It searches all attached hard disks and, if it finds an existing installation, boots directly into that disk using the existing Linux kernel. This can be useful if there are problems with the boot block (grub), or the BIOS is unable to read the boot block from the disk.

Test Memory

Runs memtest86+. This is useful to check if your memory is functional and error free.

pve-select-target-disk.png

You normally select Install Proxmox VE to start the installation. After that you get prompted to select the target hard disk(s). The Options button lets you select the target file system, which defaults to ext4. The installer uses LVM if you select ext3, ext4 or xfs as file system, and offers additional option to restrict LVM space (see below)

If you have more than one disk, you can also use ZFS as file system. ZFS supports several software RAID levels, so this is specially useful if you do not have a hardware RAID controller. The Options button lets you select the ZFS RAID level, and you can choose disks there.

pve-select-location.png

The next page just ask for basic configuration options like your location, the time zone and keyboard layout. The location is used to select a download server near you to speedup updates. The installer is usually able to auto detect those setting, so you only need to change them in rare situations when auto detection fails, or when you want to use some special keyboard layout not commonly used in your country.

pve-set-password.png

You then need to specify an email address and the superuser (root) password. The password must have at least 5 characters, but we highly recommend to use stronger passwords - here are some guidelines:

  • Use a minimum password length of 12 to 14 characters.

  • Include lowercase and uppercase alphabetic characters, numbers and symbols.

  • Avoid character repetition, keyboard patterns, dictionary words, letter or number sequences, usernames, relative or pet names, romantic links (current or past) and biographical information (e.g., ID numbers, ancestors' names or dates).

It is sometimes necessary to send notification to the system administrator, for example:

  • Information about available package updates.

  • Error messages from periodic CRON jobs.

All those notification mails will be sent to the specified email address.

pve-setup-network.png

The last step is the network configuration. Please note that you can use either IPv4 or IPv6 here, but not both. If you want to configure a dual stack node, you can easily do that after installation.

pve-installation.png

If you press Next now, installation starts to format disks, and copies packages to the target. Please wait until that is finished, then reboot the server.

Further configuration is done via the Proxmox web interface. Just point your browser to the IP address given during installation (https://youripaddress:8006).

Note Default login is "root" (realm PAM) and the root password is defined during the installation process.

2.2.1. Advanced LVM Configuration Options

The installer creates a Volume Group (VG) called pve, and additional Logical Volumes (LVs) called root, data and swap. The size of those volumes can be controlled with:

hdsize

Defines the total HD size to be used. This way you can save free space on the HD for further partitioning (i.e. for an additional PV and VG on the same hard disk that can be used for LVM storage).

swapsize

Defines the size of the swap volume. The default is the size of the installed memory, minimum 4 GB and maximum 8 GB. The resulting value cannot be greater than hdsize/8.

Note If set to 0, no swap volume will be created.
maxroot

Defines the maximum size of the root volume, which stores the operation system. The maximum limit of the root volume size is hdsize/4.

maxvz

Defines the maximum size of the data volume. The actual size of the data volume is:

datasize = hdsize - rootsize - swapsize - minfree

Where datasize cannot be bigger than maxvz.

Note In case of LVM thin, the data pool will only be created if datasize is bigger than 4GB.
Note If set to 0, no data volume will be created and the storage configuration will be adapted accordingly.
minfree

Defines the amount of free space left in LVM volume group pve. With more than 128GB storage available the default is 16GB, else hdsize/8 will be used.

Note LVM requires free space in the VG for snapshot creation (not required for lvmthin snapshots).

2.2.2. ZFS Performance Tips

ZFS uses a lot of memory, so it is best to add additional RAM if you want to use ZFS. A good calculation is 4GB plus 1GB RAM for each TB RAW disk space.

ZFS also provides the feature to use a fast SSD drive as write cache. The write cache is called the ZFS Intent Log (ZIL). You can add that after installation using the following command:

zpool add <pool-name> log </dev/path_to_fast_ssd>

2.3. Install Proxmox VE on Debian

Proxmox VE ships as a set of Debian packages, so you can install it on top of a normal Debian installation. After configuring the repositories, you need to run:

apt-get update
apt-get install proxmox-ve

Installing on top of an existing Debian installation looks easy, but it presumes that you have correctly installed the base system, and you know how you want to configure and use the local storage. Network configuration is also completely up to you.

In general, this is not trivial, especially when you use LVM or ZFS.

You can find a detailed step by step howto on the wiki.

2.4. Install from USB Stick

The Proxmox VE installation media is now a hybrid ISO image, working in two ways:

  • An ISO image file ready to burn on CD

  • A raw sector (IMG) image file ready to directly copy to flash media (USB Stick)

Using USB sticks is faster and more environmental friendly and therefore the recommended way to install Proxmox VE.

2.4.1. Prepare a USB flash drive as install medium

In order to boot the installation media, copy the ISO image to a USB media.

You need at least a 1 GB USB media.

Note Using UNetbootin or Rufus does not work.
Important Make sure that the USB media is not mounted and does not contain any important data.

2.4.2. Instructions for GNU/Linux

You can simply use dd on UNIX like systems. First download the ISO image, then plug in the USB stick. You need to find out what device name gets assigned to the USB stick (see below). Then run:

dd if=proxmox-ve_*.iso of=/dev/XYZ bs=1M
Note Be sure to replace /dev/XYZ with the correct device name.
Caution Be very careful, and do not overwrite the hard disk!
Find Correct USB Device Name

You can compare the last lines of dmesg command before and after the insertion, or use the lsblk command. Open a terminal and run:

 lsblk

Then plug in your USB media and run the command again:

 lsblk

A new device will appear, and this is the USB device you want to use.

2.4.3. Instructions for OSX

Open the terminal (query Terminal in Spotlight).

Convert the .iso file to .img using the convert option of hdiutil for example.

hdiutil convert -format UDRW -o proxmox-ve_*.dmg proxmox-ve_*.iso
Tip OS X tends to put the .dmg ending on the output file automatically.

To get the current list of devices run the command again:

diskutil list

Now insert your USB flash media and run this command again to determine the device node assigned to your flash media (e.g. /dev/diskX).

diskutil list

diskutil unmountDisk /dev/diskX
Note replace X with the disk number from the last command.
sudo dd if=proxmox-ve_*.dmg of=/dev/rdiskN bs=1m

2.4.4. Instructions for Windows

Download Etcher from https://etcher.io , select the ISO and your USB Drive.

If this doesn’t work, alternatively use the OSForensics USB installer from http://www.osforensics.com/portability.html

2.4.5. Boot your server from USB media

Connect your USB media to your server and make sure that the server boots from USB (see server BIOS). Then follow the installation wizard.

3. Host System Administration

Proxmox VE is based on the famous Debian Linux distribution. That means that you have access to the whole world of Debian packages, and the base system is well documented. The Debian Administrator's Handbook is available online, and provides a comprehensive introduction to the Debian operating system (see [Hertzog13]).

A standard Proxmox VE installation uses the default repositories from Debian, so you get bug fixes and security updates through that channel. In addition, we provide our own package repository to roll out all Proxmox VE related packages. This includes updates to some Debian packages when necessary.

We also deliver a specially optimized Linux kernel, where we enable all required virtualization and container features. That kernel includes drivers for ZFS, and several hardware drivers. For example, we ship Intel network card drivers to support their newest hardware.

The following sections will concentrate on virtualization related topics. They either explains things which are different on Proxmox VE, or tasks which are commonly used on Proxmox VE. For other topics, please refer to the standard Debian documentation.

3.1. Package Repositories

All Debian based systems use APT as package management tool. The list of repositories is defined in /etc/apt/sources.list and .list files found inside /etc/apt/sources.d/. Updates can be installed directly using apt-get, or via the GUI.

Apt sources.list files list one package repository per line, with the most preferred source listed first. Empty lines are ignored, and a # character anywhere on a line marks the remainder of that line as a comment. The information available from the configured sources is acquired by apt-get update.

File /etc/apt/sources.list
deb http://ftp.debian.org/debian stretch main contrib

# security updates
deb http://security.debian.org stretch/updates main contrib

In addition, Proxmox VE provides three different package repositories.

3.1.1. Proxmox VE Enterprise Repository

This is the default, stable and recommended repository, available for all Proxmox VE subscription users. It contains the most stable packages, and is suitable for production use. The pve-enterprise repository is enabled by default:

File /etc/apt/sources.list.d/pve-enterprise.list
deb https://enterprise.proxmox.com/debian/pve stretch pve-enterprise

As soon as updates are available, the root@pam user is notified via email about the available new packages. On the GUI, the change-log of each package can be viewed (if available), showing all details of the update. So you will never miss important security fixes.

Please note that and you need a valid subscription key to access this repository. We offer different support levels, and you can find further details at http://www.proxmox.com/en/proxmox-ve/pricing.

Note You can disable this repository by commenting out the above line using a # (at the start of the line). This prevents error messages if you do not have a subscription key. Please configure the pve-no-subscription repository in that case.

3.1.2. Proxmox VE No-Subscription Repository

As the name suggests, you do not need a subscription key to access this repository. It can be used for testing and non-production use. Its not recommended to run on production servers, as these packages are not always heavily tested and validated.

We recommend to configure this repository in /etc/apt/sources.list.

File /etc/apt/sources.list
deb http://ftp.debian.org/debian stretch main contrib

# PVE pve-no-subscription repository provided by proxmox.com,
# NOT recommended for production use
deb http://download.proxmox.com/debian/pve stretch pve-no-subscription

# security updates
deb http://security.debian.org stretch/updates main contrib

3.1.3. Proxmox VE Test Repository

Finally, there is a repository called pvetest. This one contains the latest packages and is heavily used by developers to test new features. As usual, you can configure this using /etc/apt/sources.list by adding the following line:

sources.list entry for pvetest
deb http://download.proxmox.com/debian/pve stretch pvetest
Warning the pvetest repository should (as the name implies) only be used for testing new features or bug fixes.

3.1.4. SecureApt

We use GnuPG to sign the Release files inside those repositories, and APT uses that signatures to verify that all packages are from a trusted source.

The key used for verification is already installed if you install from our installation CD. If you install by other means, you can manually download the key with:

# wget http://download.proxmox.com/debian/proxmox-ve-release-5.x.gpg -O /etc/apt/trusted.gpg.d/proxmox-ve-release-5.x.gpg

Please verify the checksum afterwards:

# sha512sum /etc/apt/trusted.gpg.d/proxmox-ve-release-5.x.gpg
ffb95f0f4be68d2e753c8875ea2f8465864a58431d5361e88789568673551501ae574283a4e0492f17d79dc67edfb173a56a6304dea39e01f249ebdabc9f074a  /etc/apt/trusted.gpg.d/proxmox-ve-release-5.x.gpg

or

# md5sum /etc/apt/trusted.gpg.d/proxmox-ve-release-5.x.gpg
511d36d0f1350c01c42a3dc9f3c27939  /etc/apt/trusted.gpg.d/proxmox-ve-release-5.x.gpg

3.2. System Software Updates

We provide regular package updates on all repositories. You can install those update using the GUI, or you can directly run the CLI command apt-get:

apt-get update
apt-get dist-upgrade
Note The apt package management system is extremely flexible and provides countless of feature - see man apt-get or [Hertzog13] for additional information.

You should do such updates at regular intervals, or when we release versions with security related fixes. Major system upgrades are announced at the Proxmox VE Community Forum. Those announcement also contain detailed upgrade instructions.

Tip We recommend to run regular upgrades, because it is important to get the latest security updates.

3.3. Network Configuration

Network configuration can be done either via the GUI, or by manually editing the file /etc/network/interfaces, which contains the whole network configuration. The interfaces(5) manual page contains the complete format description. All Proxmox VE tools try hard to keep direct user modifications, but using the GUI is still preferable, because it protects you from errors.

Once the network is configured, you can use the Debian traditional tools ifup and ifdown commands to bring interfaces up and down.

Note Proxmox VE does not write changes directly to /etc/network/interfaces. Instead, we write into a temporary file called /etc/network/interfaces.new, and commit those changes when you reboot the node.

3.3.1. Naming Conventions

We currently use the following naming conventions for device names:

  • Ethernet devices: en*, systemd network interface names. This naming scheme is used for new Proxmox VE installations since version 5.0.

  • Ethernet devices: eth[N], where 0 ≤ N (eth0, eth1, …) This naming scheme is used for Proxmox VE hosts which were installed before the 5.0 release. When upgrading to 5.0, the names are kept as-is.

  • Bridge names: vmbr[N], where 0 ≤ N ≤ 4094 (vmbr0 - vmbr4094)

  • Bonds: bond[N], where 0 ≤ N (bond0, bond1, …)

  • VLANs: Simply add the VLAN number to the device name, separated by a period (eno1.50, bond1.30)

This makes it easier to debug networks problems, because the device name implies the device type.

Systemd Network Interface Names

Systemd uses the two character prefix en for Ethernet network devices. The next characters depends on the device driver and the fact which schema matches first.

  • o<index>[n<phys_port_name>|d<dev_port>] — devices on board

  • s<slot>[f<function>][n<phys_port_name>|d<dev_port>] — device by hotplug id

  • [P<domain>]p<bus>s<slot>[f<function>][n<phys_port_name>|d<dev_port>] — devices by bus id

  • x<MAC> — device by MAC address

The most common patterns are:

  • eno1 — is the first on board NIC

  • enp3s0f1 — is the NIC on pcibus 3 slot 0 and use the NIC function 1.

For more information see Predictable Network Interface Names.

3.3.2. Choosing a network configuration

Depending on your current network organization and your resources you can choose either a bridged, routed, or masquerading networking setup.

Proxmox VE server in a private LAN, using an external gateway to reach the internet

The Bridged model makes the most sense in this case, and this is also the default mode on new Proxmox VE installations. Each of your Guest system will have a virtual interface attached to the Proxmox VE bridge. This is similar in effect to having the Guest network card directly connected to a new switch on your LAN, the Proxmox VE host playing the role of the switch.

Proxmox VE server at hosting provider, with public IP ranges for Guests

For this setup, you can use either a Bridged or Routed model, depending on what your provider allows.

Proxmox VE server at hosting provider, with a single public IP address

In that case the only way to get outgoing network accesses for your guest systems is to use Masquerading. For incoming network access to your guests, you will need to configure Port Forwarding.

For further flexibility, you can configure VLANs (IEEE 802.1q) and network bonding, also known as "link aggregation". That way it is possible to build complex and flexible virtual networks.

3.3.3. Default Configuration using a Bridge

Bridges are like physical network switches implemented in software. All VMs can share a single bridge, or you can create multiple bridges to separate network domains. Each host can have up to 4094 bridges.

The installation program creates a single bridge named vmbr0, which is connected to the first Ethernet card. The corresponding configuration in /etc/network/interfaces might look like this:

auto lo
iface lo inet loopback

iface eno1 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.10.2
        netmask 255.255.255.0
        gateway 192.168.10.1
        bridge_ports eno1
        bridge_stp off
        bridge_fd 0

Virtual machines behave as if they were directly connected to the physical network. The network, in turn, sees each virtual machine as having its own MAC, even though there is only one network cable connecting all of these VMs to the network.

3.3.4. Routed Configuration

Most hosting providers do not support the above setup. For security reasons, they disable networking as soon as they detect multiple MAC addresses on a single interface.

Tip Some providers allows you to register additional MACs on there management interface. This avoids the problem, but is clumsy to configure because you need to register a MAC for each of your VMs.

You can avoid the problem by “routing” all traffic via a single interface. This makes sure that all network packets use the same MAC address.

A common scenario is that you have a public IP (assume 198.51.100.5 for this example), and an additional IP block for your VMs (203.0.113.16/29). We recommend the following setup for such situations:

auto lo
iface lo inet loopback

auto eno1
iface eno1 inet static
        address  198.51.100.5
        netmask  255.255.255.0
        gateway  198.51.100.1
        post-up echo 1 > /proc/sys/net/ipv4/ip_forward
        post-up echo 1 > /proc/sys/net/ipv4/conf/eno1/proxy_arp


auto vmbr0
iface vmbr0 inet static
        address  203.0.113.17
        netmask  255.255.255.248
        bridge_ports none
        bridge_stp off
        bridge_fd 0

3.3.5. Masquerading (NAT) with iptables

Masquerading allows guests having only a private IP address to access the network by using the host IP address for outgoing traffic. Each outgoing packet is rewritten by iptables to appear as originating from the host, and responses are rewritten accordingly to be routed to the original sender.

auto lo
iface lo inet loopback

auto eno1
#real IP address
iface eno1 inet static
        address  198.51.100.5
        netmask  255.255.255.0
        gateway  198.51.100.1

auto vmbr0
#private sub network
iface vmbr0 inet static
        address  10.10.10.1
        netmask  255.255.255.0
        bridge_ports none
        bridge_stp off
        bridge_fd 0

        post-up echo 1 > /proc/sys/net/ipv4/ip_forward
        post-up   iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o eno1 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o eno1 -j MASQUERADE

3.3.6. Linux Bond

Bonding (also called NIC teaming or Link Aggregation) is a technique for binding multiple NIC’s to a single network device. It is possible to achieve different goals, like make the network fault-tolerant, increase the performance or both together.

High-speed hardware like Fibre Channel and the associated switching hardware can be quite expensive. By doing link aggregation, two NICs can appear as one logical interface, resulting in double speed. This is a native Linux kernel feature that is supported by most switches. If your nodes have multiple Ethernet ports, you can distribute your points of failure by running network cables to different switches and the bonded connection will failover to one cable or the other in case of network trouble.

Aggregated links can improve live-migration delays and improve the speed of replication of data between Proxmox VE Cluster nodes.

There are 7 modes for bonding:

  • Round-robin (balance-rr): Transmit network packets in sequential order from the first available network interface (NIC) slave through the last. This mode provides load balancing and fault tolerance.

  • Active-backup (active-backup): Only one NIC slave in the bond is active. A different slave becomes active if, and only if, the active slave fails. The single logical bonded interface’s MAC address is externally visible on only one NIC (port) to avoid distortion in the network switch. This mode provides fault tolerance.

  • XOR (balance-xor): Transmit network packets based on [(source MAC address XOR’d with destination MAC address) modulo NIC slave count]. This selects the same NIC slave for each destination MAC address. This mode provides load balancing and fault tolerance.

  • Broadcast (broadcast): Transmit network packets on all slave network interfaces. This mode provides fault tolerance.

  • IEEE 802.3ad Dynamic link aggregation (802.3ad)(LACP): Creates aggregation groups that share the same speed and duplex settings. Utilizes all slave network interfaces in the active aggregator group according to the 802.3ad specification.

  • Adaptive transmit load balancing (balance-tlb): Linux bonding driver mode that does not require any special network-switch support. The outgoing network packet traffic is distributed according to the current load (computed relative to the speed) on each network interface slave. Incoming traffic is received by one currently designated slave network interface. If this receiving slave fails, another slave takes over the MAC address of the failed receiving slave.

  • Adaptive load balancing (balance-alb): Includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic, and does not require any special network switch support. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the NIC slaves in the single logical bonded interface such that different network-peers use different MAC addresses for their network packet traffic.

If your switch support the LACP (IEEE 802.3ad) protocol then we recommend using the corresponding bonding mode (802.3ad). Otherwise you should generally use the active-backup mode.
If you intend to run your cluster network on the bonding interfaces, then you have to use active-passive mode on the bonding interfaces, other modes are unsupported.

The following bond configuration can be used as distributed/shared storage network. The benefit would be that you get more speed and the network will be fault-tolerant.

Example: Use bond with fixed IP address
auto lo
iface lo inet loopback

iface eno1 inet manual

iface eno2 inet manual

auto bond0
iface bond0 inet static
      slaves eno1 eno2
      address  192.168.1.2
      netmask  255.255.255.0
      bond_miimon 100
      bond_mode 802.3ad
      bond_xmit_hash_policy layer2+3

auto vmbr0
iface vmbr0 inet static
        address  10.10.10.2
        netmask  255.255.255.0
        gateway  10.10.10.1
        bridge_ports eno1
        bridge_stp off
        bridge_fd 0

Another possibility it to use the bond directly as bridge port. This can be used to make the guest network fault-tolerant.

Example: Use a bond as bridge port
auto lo
iface lo inet loopback

iface eno1 inet manual

iface eno2 inet manual

auto bond0
iface bond0 inet manual
      slaves eno1 eno2
      bond_miimon 100
      bond_mode 802.3ad
      bond_xmit_hash_policy layer2+3

auto vmbr0
iface vmbr0 inet static
        address  10.10.10.2
        netmask  255.255.255.0
        gateway  10.10.10.1
        bridge_ports bond0
        bridge_stp off
        bridge_fd 0

3.3.7. VLAN 802.1Q

A virtual LAN (VLAN) is a broadcast domain that is partitioned and isolated in the network at layer two. So it is possible to have multiple networks (4096) in a physical network, each independent of the other ones.

Each VLAN network is identified by a number often called tag. Network packages are then tagged to identify which virtual network they belong to.

VLAN for Guest Networks

Proxmox VE supports this setup out of the box. You can specify the VLAN tag when you create a VM. The VLAN tag is part of the guest network confinuration. The networking layer supports differnet modes to implement VLANs, depending on the bridge configuration:

  • VLAN awareness on the Linux bridge: In this case, each guest’s virtual network card is assigned to a VLAN tag, which is transparently supported by the Linux bridge. Trunk mode is also possible, but that makes the configuration in the guest necessary.

  • "traditional" VLAN on the Linux bridge: In contrast to the VLAN awareness method, this method is not transparent and creates a VLAN device with associated bridge for each VLAN. That is, if e.g. in our default network, a guest VLAN 5 is used to create eno1.5 and vmbr0v5, which remains until rebooting.

  • Open vSwitch VLAN: This mode uses the OVS VLAN feature.

  • Guest configured VLAN: VLANs are assigned inside the guest. In this case, the setup is completely done inside the guest and can not be influenced from the outside. The benefit is that you can use more than one VLAN on a single virtual NIC.

VLAN on the Host

To allow host communication with an isolated network. It is possible to apply VLAN tags to any network device (NIC, Bond, Bridge). In general, you should configure the VLAN on the interface with the least abstraction layers between itself and the physical NIC.

For example, in a default configuration where you want to place the host management address on a separate VLAN.

Note In the examples we use the VLAN at bridge level to ensure the correct function of VLAN 5 in the guest network, but in combination with VLAN anwareness bridge this it will not work for guest network VLAN 5. The downside of this setup is more CPU usage.
Example: Use VLAN 5 for the Proxmox VE management IP
auto lo
iface lo inet loopback

iface eno1 inet manual

iface eno1.5 inet manual

auto vmbr0v5
iface vmbr0v5 inet static
        address  10.10.10.2
        netmask  255.255.255.0
        gateway  10.10.10.1
        bridge_ports eno1.5
        bridge_stp off
        bridge_fd 0

auto vmbr0
iface vmbr0 inet manual
        bridge_ports eno1
        bridge_stp off
        bridge_fd 0

The next example is the same setup but a bond is used to make this network fail-safe.

Example: Use VLAN 5 with bond0 for the Proxmox VE management IP
auto lo
iface lo inet loopback

iface eno1 inet manual

iface eno2 inet manual

auto bond0
iface bond0 inet manual
      slaves eno1 eno2
      bond_miimon 100
      bond_mode 802.3ad
      bond_xmit_hash_policy layer2+3

iface bond0.5 inet manual

auto vmbr0v5
iface vmbr0v5 inet static
        address  10.10.10.2
        netmask  255.255.255.0
        gateway  10.10.10.1
        bridge_ports bond0.5
        bridge_stp off
        bridge_fd 0

auto vmbr0
iface vmbr0 inet manual
        bridge_ports bond0
        bridge_stp off
        bridge_fd 0

3.4. Time Synchronization

The Proxmox VE cluster stack itself relies heavily on the fact that all the nodes have precisely synchronized time. Some other components, like Ceph, also refuse to work properly if the local time on nodes is not in sync.

Time synchronization between nodes can be achieved with the “Network Time Protocol” (NTP). Proxmox VE uses systemd-timesyncd as NTP client by default, preconfigured to use a set of public servers. This setup works out of the box in most cases.

3.4.1. Using Custom NTP Servers

In some cases, it might be desired to not use the default NTP servers. For example, if your Proxmox VE nodes do not have access to the public internet (e.g., because of restrictive firewall rules), you need to setup local NTP servers and tell systemd-timesyncd to use them:

File /etc/systemd/timesyncd.conf
[Time]
NTP=ntp1.example.com ntp2.example.com ntp3.example.com ntp4.example.com

After restarting the synchronization service (systemctl restart systemd-timesyncd) you should verify that your newly configured NTP servers are used by checking the journal (journalctl --since -1h -u systemd-timesyncd):

...
Oct 07 14:58:36 node1 systemd[1]: Stopping Network Time Synchronization...
Oct 07 14:58:36 node1 systemd[1]: Starting Network Time Synchronization...
Oct 07 14:58:36 node1 systemd[1]: Started Network Time Synchronization.
Oct 07 14:58:36 node1 systemd-timesyncd[13514]: Using NTP server 10.0.0.1:123 (ntp1.example.com).
Oct 07 14:58:36 nora systemd-timesyncd[13514]: interval/delta/delay/jitter/drift 64s/-0.002s/0.020s/0.000s/-31ppm
...

3.5. External Metric Server

Starting with Proxmox VE 4.0, you can define external metric servers, which will be sent various stats about your hosts, virtual machines and storages.

Currently supported are:

The server definitions are saved in /etc/pve/status.cfg

3.5.1. Graphite server configuration

The definition of a server is:

graphite:
   server your-server
   port your-port
   path your-path

where your-port defaults to 2003 and your-path defaults to proxmox

Proxmox VE sends the data over udp, so the graphite server has to be configured for this

3.5.2. Influxdb plugin configuration

The definition is:

influxdb:
   server your-server
   port your-port

Proxmox VE sends the data over udp, so the influxdb server has to be configured for this

Here is an example configuration for influxdb (on your influxdb server):

[[udp]]
  enabled = true
  bind-address = "0.0.0.0:8089"
  database = "proxmox"
  batch-size = 1000
  batch-timeout = "1s"

With this configuration, your server listens on all IP addresses on port 8089, and writes the data in the proxmox database

3.6. Disk Health Monitoring

Although a robust and redundant storage is recommended, it can be very helpful to monitor the health of your local disks.

Starting with Proxmox VE 4.3, the package smartmontools
[smartmontools homepage https://www.smartmontools.org]
is installed and required. This is a set of tools to monitor and control the S.M.A.R.T. system for local hard disks.

You can get the status of a disk by issuing the following command:

# smartctl -a /dev/sdX

where /dev/sdX is the path to one of your local disks.

If the output says:

SMART support is: Disabled

you can enable it with the command:

# smartctl -s on /dev/sdX

For more information on how to use smartctl, please see man smartctl.

By default, smartmontools daemon smartd is active and enabled, and scans the disks under /dev/sdX and /dev/hdX every 30 minutes for errors and warnings, and sends an e-mail to root if it detects a problem.

For more information about how to configure smartd, please see man smartd and man smartd.conf.

If you use your hard disks with a hardware raid controller, there are most likely tools to monitor the disks in the raid array and the array itself. For more information about this, please refer to the vendor of your raid controller.

3.7. Logical Volume Manager (LVM)

Most people install Proxmox VE directly on a local disk. The Proxmox VE installation CD offers several options for local disk management, and the current default setup uses LVM. The installer let you select a single disk for such setup, and uses that disk as physical volume for the Volume Group (VG) pve. The following output is from a test installation using a small 8GB disk:

# pvs
  PV         VG   Fmt  Attr PSize PFree
  /dev/sda3  pve  lvm2 a--  7.87g 876.00m

# vgs
  VG   #PV #LV #SN Attr   VSize VFree
  pve    1   3   0 wz--n- 7.87g 876.00m

The installer allocates three Logical Volumes (LV) inside this VG:

# lvs
  LV   VG   Attr       LSize   Pool Origin Data%  Meta%
  data pve  twi-a-tz--   4.38g             0.00   0.63
  root pve  -wi-ao----   1.75g
  swap pve  -wi-ao---- 896.00m
root

Formatted as ext4, and contains the operation system.

swap

Swap partition

data

This volume uses LVM-thin, and is used to store VM images. LVM-thin is preferable for this task, because it offers efficient support for snapshots and clones.

For Proxmox VE versions up to 4.1, the installer creates a standard logical volume called “data”, which is mounted at /var/lib/vz.

Starting from version 4.2, the logical volume “data” is a LVM-thin pool, used to store block based guest images, and /var/lib/vz is simply a directory on the root file system.

3.7.1. Hardware

We highly recommend to use a hardware RAID controller (with BBU) for such setups. This increases performance, provides redundancy, and make disk replacements easier (hot-pluggable).

LVM itself does not need any special hardware, and memory requirements are very low.

3.7.2. Bootloader

We install two boot loaders by default. The first partition contains the standard GRUB boot loader. The second partition is an EFI System Partition (ESP), which makes it possible to boot on EFI systems.

3.7.3. Creating a Volume Group

Let’s assume we have an empty disk /dev/sdb, onto which we want to create a volume group named “vmdata”.

Caution Please note that the following commands will destroy all existing data on /dev/sdb.

First create a partition.

# sgdisk -N 1 /dev/sdb

Create a Physical Volume (PV) without confirmation and 250K metadatasize.

# pvcreate --metadatasize 250k -y -ff /dev/sdb1

Create a volume group named “vmdata” on /dev/sdb1

# vgcreate vmdata /dev/sdb1

3.7.4. Creating an extra LV for /var/lib/vz

This can be easily done by creating a new thin LV.

# lvcreate -n <Name> -V <Size[M,G,T]> <VG>/<LVThin_pool>

A real world example:

# lvcreate -n vz -V 10G pve/data

Now a filesystem must be created on the LV.

# mkfs.ext4 /dev/pve/vz

At last this has to be mounted.

Warning be sure that /var/lib/vz is empty. On a default installation it’s not.

To make it always accessible add the following line in /etc/fstab.

# echo '/dev/pve/vz /var/lib/vz ext4 defaults 0 2' >> /etc/fstab

3.7.5. Resizing the thin pool

Resize the LV and the metadata pool can be achieved with the following command.

# lvresize --size +<size[\M,G,T]> --poolmetadatasize +<size[\M,G]> <VG>/<LVThin_pool>
Note When extending the data pool, the metadata pool must also be extended.

3.7.6. Create a LVM-thin pool

A thin pool has to be created on top of a volume group. How to create a volume group see Section LVM.

# lvcreate -L 80G -T -n vmstore vmdata

3.8. ZFS on Linux

ZFS is a combined file system and logical volume manager designed by Sun Microsystems. Starting with Proxmox VE 3.4, the native Linux kernel port of the ZFS file system is introduced as optional file system and also as an additional selection for the root file system. There is no need for manually compile ZFS modules - all packages are included.

By using ZFS, its possible to achieve maximum enterprise features with low budget hardware, but also high performance systems by leveraging SSD caching or even SSD only setups. ZFS can replace cost intense hardware raid cards by moderate CPU and memory load combined with easy management.

General ZFS advantages
  • Easy configuration and management with Proxmox VE GUI and CLI.

  • Reliable

  • Protection against data corruption

  • Data compression on file system level

  • Snapshots

  • Copy-on-write clone

  • Various raid levels: RAID0, RAID1, RAID10, RAIDZ-1, RAIDZ-2 and RAIDZ-3

  • Can use SSD for cache

  • Self healing

  • Continuous integrity checking

  • Designed for high storage capacities

  • Protection against data corruption

  • Asynchronous replication over network

  • Open Source

  • Encryption

3.8.1. Hardware

ZFS depends heavily on memory, so you need at least 8GB to start. In practice, use as much you can get for your hardware/budget. To prevent data corruption, we recommend the use of high quality ECC RAM.

If you use a dedicated cache and/or log disk, you should use an enterprise class SSD (e.g. Intel SSD DC S3700 Series). This can increase the overall performance significantly.

Important Do not use ZFS on top of hardware controller which has its own cache management. ZFS needs to directly communicate with disks. An HBA adapter is the way to go, or something like LSI controller flashed in “IT” mode.

If you are experimenting with an installation of Proxmox VE inside a VM (Nested Virtualization), don’t use virtio for disks of that VM, since they are not supported by ZFS. Use IDE or SCSI instead (works also with virtio SCSI controller type).

3.8.2. Installation as Root File System

When you install using the Proxmox VE installer, you can choose ZFS for the root file system. You need to select the RAID type at installation time:

RAID0

Also called “striping”. The capacity of such volume is the sum of the capacities of all disks. But RAID0 does not add any redundancy, so the failure of a single drive makes the volume unusable.

RAID1

Also called “mirroring”. Data is written identically to all disks. This mode requires at least 2 disks with the same size. The resulting capacity is that of a single disk.

RAID10

A combination of RAID0 and RAID1. Requires at least 4 disks.

RAIDZ-1

A variation on RAID-5, single parity. Requires at least 3 disks.

RAIDZ-2

A variation on RAID-5, double parity. Requires at least 4 disks.

RAIDZ-3

A variation on RAID-5, triple parity. Requires at least 5 disks.

The installer automatically partitions the disks, creates a ZFS pool called rpool, and installs the root file system on the ZFS subvolume rpool/ROOT/pve-1.

Another subvolume called rpool/data is created to store VM images. In order to use that with the Proxmox VE tools, the installer creates the following configuration entry in /etc/pve/storage.cfg:

zfspool: local-zfs
        pool rpool/data
        sparse
        content images,rootdir

After installation, you can view your ZFS pool status using the zpool command:

# zpool status
  pool: rpool
 state: ONLINE
  scan: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            sda2    ONLINE       0     0     0
            sdb2    ONLINE       0     0     0
          mirror-1  ONLINE       0     0     0
            sdc     ONLINE       0     0     0
            sdd     ONLINE       0     0     0

errors: No known data errors

The zfs command is used configure and manage your ZFS file systems. The following command lists all file systems after installation:

# zfs list
NAME               USED  AVAIL  REFER  MOUNTPOINT
rpool             4.94G  7.68T    96K  /rpool
rpool/ROOT         702M  7.68T    96K  /rpool/ROOT
rpool/ROOT/pve-1   702M  7.68T   702M  /
rpool/data          96K  7.68T    96K  /rpool/data
rpool/swap        4.25G  7.69T    64K  -

3.8.3. Bootloader

The default ZFS disk partitioning scheme does not use the first 2048 sectors. This gives enough room to install a GRUB boot partition. The Proxmox VE installer automatically allocates that space, and installs the GRUB boot loader there. If you use a redundant RAID setup, it installs the boot loader on all disk required for booting. So you can boot even if some disks fail.

Note It is not possible to use ZFS as root file system with UEFI boot.

3.8.4. ZFS Administration

This section gives you some usage examples for common tasks. ZFS itself is really powerful and provides many options. The main commands to manage ZFS are zfs and zpool. Both commands come with great manual pages, which can be read with:

# man zpool
# man zfs
Create a new zpool

To create a new pool, at least one disk is needed. The ashift should have the same sector-size (2 power of ashift) or larger as the underlying disk.

zpool create -f -o ashift=12 <pool> <device>

To activate compression

zfs set compression=lz4 <pool>
Create a new pool with RAID-0

Minimum 1 Disk

zpool create -f -o ashift=12 <pool> <device1> <device2>
Create a new pool with RAID-1

Minimum 2 Disks

zpool create -f -o ashift=12 <pool> mirror <device1> <device2>
Create a new pool with RAID-10

Minimum 4 Disks

zpool create -f -o ashift=12 <pool> mirror <device1> <device2> mirror <device3> <device4>
Create a new pool with RAIDZ-1

Minimum 3 Disks

zpool create -f -o ashift=12 <pool> raidz1 <device1> <device2> <device3>
Create a new pool with RAIDZ-2

Minimum 4 Disks

zpool create -f -o ashift=12 <pool> raidz2 <device1> <device2> <device3> <device4>
Create a new pool with cache (L2ARC)

It is possible to use a dedicated cache drive partition to increase the performance (use SSD).

As <device> it is possible to use more devices, like it’s shown in "Create a new pool with RAID*".

zpool create -f -o ashift=12 <pool> <device> cache <cache_device>
Create a new pool with log (ZIL)

It is possible to use a dedicated cache drive partition to increase the performance(SSD).

As <device> it is possible to use more devices, like it’s shown in "Create a new pool with RAID*".

zpool create -f -o ashift=12 <pool> <device> log <log_device>
Add cache and log to an existing pool

If you have an pool without cache and log. First partition the SSD in 2 partition with parted or gdisk

Important Always use GPT partition tables.

The maximum size of a log device should be about half the size of physical memory, so this is usually quite small. The rest of the SSD can be used as cache.

zpool add -f <pool> log <device-part1> cache <device-part2>
Changing a failed device
zpool replace -f <pool> <old device> <new-device>

3.8.5. Activate E-Mail Notification

ZFS comes with an event daemon, which monitors events generated by the ZFS kernel module. The daemon can also send emails on ZFS events like pool errors. Newer ZFS packages ships the daemon in a separate package, and you can install it using apt-get:

# apt-get install zfs-zed

To activate the daemon it is necessary to edit /etc/zfs/zed.d/zed.rc with your favourite editor, and uncomment the ZED_EMAIL_ADDR setting:

ZED_EMAIL_ADDR="root"

Please note Proxmox VE forwards mails to root to the email address configured for the root user.

Important The only setting that is required is ZED_EMAIL_ADDR. All other settings are optional.

3.8.6. Limit ZFS Memory Usage

It is good to use at most 50 percent (which is the default) of the system memory for ZFS ARC to prevent performance shortage of the host. Use your preferred editor to change the configuration in /etc/modprobe.d/zfs.conf and insert:

options zfs zfs_arc_max=8589934592

This example setting limits the usage to 8GB.

Important

If your root file system is ZFS you must update your initramfs every time this value changes:

update-initramfs -u
SWAP on ZFS

SWAP on ZFS on Linux may generate some troubles, like blocking the server or generating a high IO load, often seen when starting a Backup to an external Storage.

We strongly recommend to use enough memory, so that you normally do not run into low memory situations. Additionally, you can lower the “swappiness” value. A good value for servers is 10:

sysctl -w vm.swappiness=10

To make the swappiness persistent, open /etc/sysctl.conf with an editor of your choice and add the following line:

vm.swappiness = 10
Table 1. Linux kernel swappiness parameter values
Value Strategy

vm.swappiness = 0

The kernel will swap only to avoid an out of memory condition

vm.swappiness = 1

Minimum amount of swapping without disabling it entirely.

vm.swappiness = 10

This value is sometimes recommended to improve performance when sufficient memory exists in a system.

vm.swappiness = 60

The default value.

vm.swappiness = 100

The kernel will swap aggressively.

3.9. Certificate Management

3.9.1. Certificates for communication within the cluster

Each Proxmox VE cluster creates its own internal Certificate Authority (CA) and generates a self-signed certificate for each node. These certificates are used for encrypted communication with the cluster’s pveproxy service and the Shell/Console feature if SPICE is used.

The CA certificate and key are stored in the Proxmox Cluster File System (pmxcfs).

3.9.2. Certificates for API and web GUI

The REST API and web GUI are provided by the pveproxy service, which runs on each node.

You have the following options for the certificate used by pveproxy:

  1. By default the node-specific certificate in /etc/pve/nodes/NODENAME/pve-ssl.pem is used. This certificate is signed by the cluster CA and therefore not trusted by browsers and operating systems by default.

  2. use an externally provided certificate (e.g. signed by a commercial CA).

  3. use ACME (e.g., Let’s Encrypt) to get a trusted certificate with automatic renewal.

For options 2 and 3 the file /etc/pve/local/pveproxy-ssl.pem (and /etc/pve/local/pveproxy-ssl.key, which needs to be without password) is used.

Certificates are managed with the Proxmox VE Node management command (see the pvenode(1) manpage).

Warning Do not replace or manually modify the automatically generated node certificate files in /etc/pve/local/pve-ssl.pem and /etc/pve/local/pve-ssl.key or the cluster CA files in /etc/pve/pve-root-ca.pem and /etc/pve/priv/pve-root-ca.key.
Getting trusted certificates via ACME

Proxmox VE includes an implementation of the Automatic Certificate Management Environment ACME protocol, allowing Proxmox VE admins to interface with Let’s Encrypt for easy setup of trusted TLS certificates which are accepted out of the box on most modern operating systems and browsers.

Currently the two ACME endpoints implemented are Let’s Encrypt (LE) and its staging environment (see https://letsencrypt.org), both using the standalone HTTP challenge.

Because of rate-limits you should use LE staging for experiments.

There are a few prerequisites to use Let’s Encrypt:

  1. Port 80 of the node needs to be reachable from the internet.

  2. There must be no other listener on port 80.

  3. The requested (sub)domain needs to resolve to a public IP of the Node.

  4. You have to accept the ToS of Let’s Encrypt.

At the moment the GUI uses only the default ACME account.

Example: Sample pvenode invocation for using Let’s Encrypt certificates
root@proxmox:~# pvenode acme account register default mail@example.invalid
Directory endpoints:
0) Let's Encrypt V2 (https://acme-v02.api.letsencrypt.org/directory)
1) Let's Encrypt V2 Staging (https://acme-staging-v02.api.letsencrypt.org/directory)
2) Custom
Enter selection:
1

Attempting to fetch Terms of Service from 'https://acme-staging-v02.api.letsencrypt.org/directory'..
Terms of Service: https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf
Do you agree to the above terms? [y|N]y

Attempting to register account with 'https://acme-staging-v02.api.letsencrypt.org/directory'..
Generating ACME account key..
Registering ACME account..
Registration successful, account URL: 'https://acme-staging-v02.api.letsencrypt.org/acme/acct/xxxxxxx'
Task OK
root@proxmox:~# pvenode acme account list
default
root@proxmox:~# pvenode config set --acme domains=example.invalid
root@proxmox:~# pvenode acme cert order
Loading ACME account details
Placing ACME order
Order URL: https://acme-staging-v02.api.letsencrypt.org/acme/order/xxxxxxxxxxxxxx

Getting authorization details from
'https://acme-staging-v02.api.letsencrypt.org/acme/authz/xxxxxxxxxxxxxxxxxxxxx-xxxxxxxxxxxxx-xxxxxxx'
... pending!
Setting up webserver
Triggering validation
Sleeping for 5 seconds
Status is 'valid'!

All domains validated!

Creating CSR
Finalizing order
Checking order status
valid!

Downloading certificate
Setting pveproxy certificate and key
Restarting pveproxy
Task OK
Switching from the staging to the regular ACME directory

Changing the ACME directory for an account is unsupported. If you want to switch an account from the staging ACME directory to the regular, trusted, one you need to deactivate it and recreate it.

This procedure is also needed to change the default ACME account used in the GUI.

Example: Changing the default ACME account from the staging to the regular directory
root@proxmox:~# pvenode acme account info default
Directory URL: https://acme-staging-v02.api.letsencrypt.org/directory
Account URL: https://acme-staging-v02.api.letsencrypt.org/acme/acct/6332194
Terms Of Service: https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf

Account information:
ID: xxxxxxx
Contact:
        - mailto:example@proxmox.com
Creation date: 2018-07-31T08:41:44.54196435Z
Initial IP: 192.0.2.1
Status: valid

root@proxmox:~# pvenode acme account deactivate default
Renaming account file from '/etc/pve/priv/acme/default' to '/etc/pve/priv/acme/_deactivated_default_4'
Task OK

root@proxmox:~# pvenode acme account register default example@proxmox.com
Directory endpoints:
0) Let's Encrypt V2 (https://acme-v02.api.letsencrypt.org/directory)
1) Let's Encrypt V2 Staging (https://acme-staging-v02.api.letsencrypt.org/directory)
2) Custom
Enter selection:
0

Attempting to fetch Terms of Service from 'https://acme-v02.api.letsencrypt.org/directory'..
Terms of Service: https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf
Do you agree to the above terms? [y|N]y

Attempting to register account with 'https://acme-v02.api.letsencrypt.org/directory'..
Generating ACME account key..
Registering ACME account..
Registration successful, account URL: 'https://acme-v02.api.letsencrypt.org/acme/acct/39335247'
Task OK
Automatic renewal of ACME certificates

If a node has been successfully configured with an ACME-provided certificate (either via pvenode or via the GUI), the certificate will be automatically renewed by the pve-daily-update.service. Currently, renewal will be attempted if the certificate has expired or will expire in the next 30 days.

4. Hyper-converged Infrastructure

Proxmox VE is a virtualization platform that tightly integrates compute, storage and networking resources, manages highly available clusters, backup/restore as well as disaster recovery. All components are software-defined and compatible with one another.

Therefore it is possible to administrate them like a single system via the centralized web management interface. These capabilities make Proxmox VE an ideal choice to deploy and manage an open source hyper-converged infrastructure.

4.1. Benefits of a Hyper-Converged Infrastructure (HCI) with Proxmox VE

A hyper-converged infrastructure is especially useful for deployments in which a high infrastructure demand meets a low administration budget, for distributed setups such as remote and branch office environments or for virtual private and public clouds.

HCI provides the following advantages:

  • Scalability: seamless expansion of compute, network and storage devices (i.e. scale up servers and storage quickly and independently from each other).

  • Low cost: Proxmox VE is open source and integrates all components you need such as compute, storage, networking, backup, and management center. It can replace an expensive compute/storage infrastructure.

  • Data protection and efficiency: services such as backup and disaster recovery are integrated.

  • Simplicity: easy configuration and centralized administration.

  • Open Source: No vendor lock-in.

4.2. Manage Ceph Services on Proxmox VE Nodes

gui-ceph-status.png

Proxmox VE unifies your compute and storage systems, i.e. you can use the same physical nodes within a cluster for both computing (processing VMs and containers) and replicated storage. The traditional silos of compute and storage resources can be wrapped up into a single hyper-converged appliance. Separate storage networks (SANs) and connections via network attached storages (NAS) disappear. With the integration of Ceph, an open source software-defined storage platform, Proxmox VE has the ability to run and manage Ceph storage directly on the hypervisor nodes.

Ceph is a distributed object store and file system designed to provide excellent performance, reliability and scalability.

Some advantages of Ceph on Proxmox VE are:
  • Easy setup and management with CLI and GUI support

  • Thin provisioning

  • Snapshots support

  • Self healing

  • Scalable to the exabyte level

  • Setup pools with different performance and redundancy characteristics

  • Data is replicated, making it fault tolerant

  • Runs on economical commodity hardware

  • No need for hardware RAID controllers

  • Open source

For small to mid sized deployments, it is possible to install a Ceph server for RADOS Block Devices (RBD) directly on your Proxmox VE cluster nodes, see Ceph RADOS Block Devices (RBD). Recent hardware has plenty of CPU power and RAM, so running storage services and VMs on the same node is possible.

To simplify management, we provide pveceph - a tool to install and manage Ceph services on Proxmox VE nodes.

Ceph consists of a couple of Daemons
[Ceph intro http://docs.ceph.com/docs/master/start/intro/]
, for use as a RBD storage:
  • Ceph Monitor (ceph-mon)

  • Ceph Manager (ceph-mgr)

  • Ceph OSD (ceph-osd; Object Storage Daemon)

Tip We recommend to get familiar with the Ceph vocabulary.
[Ceph glossary http://docs.ceph.com/docs/luminous/glossary]

4.2.1. Precondition

To build a Proxmox Ceph Cluster there should be at least three (preferably) identical servers for the setup.

A 10Gb network, exclusively used for Ceph, is recommended. A meshed network setup is also an option if there are no 10Gb switches available, see our wiki article
[Full Mesh Network for Ceph https://pve.proxmox.com/wiki/Full_Mesh_Network_for_Ceph_Server]
.

Check also the recommendations from Ceph’s website.

Avoid RAID

As Ceph handles data object redundancy and multiple parallel writes to disks (OSDs) on its own, using a RAID controller normally doesn’t improve performance or availability. On the contrary, Ceph is designed to handle whole disks on it’s own, without any abstraction in between. RAID controller are not designed for the Ceph use case and may complicate things and sometimes even reduce performance, as their write and caching algorithms may interfere with the ones from Ceph.

Warning Avoid RAID controller, use host bus adapter (HBA) instead.

4.2.2. Installation of Ceph Packages

On each node run the installation script as follows:

pveceph install

This sets up an apt package repository in /etc/apt/sources.list.d/ceph.list and installs the required software.

4.2.3. Creating initial Ceph configuration

gui-ceph-config.png

After installation of packages, you need to create an initial Ceph configuration on just one node, based on your network (10.10.10.0/24 in the following example) dedicated for Ceph:

pveceph init --network 10.10.10.0/24

This creates an initial configuration at /etc/pve/ceph.conf. That file is automatically distributed to all Proxmox VE nodes by using pmxcfs. The command also creates a symbolic link from /etc/ceph/ceph.conf pointing to that file. So you can simply run Ceph commands without the need to specify a configuration file.

4.2.4. Creating Ceph Monitors

gui-ceph-monitor.png

The Ceph Monitor (MON)
[Ceph Monitor http://docs.ceph.com/docs/luminous/start/intro/]
maintains a master copy of the cluster map. For high availability you need to have at least 3 monitors.

On each node where you want to place a monitor (three monitors are recommended), create it by using the Ceph → Monitor tab in the GUI or run.

pveceph createmon

This will also install the needed Ceph Manager (ceph-mgr) by default. If you do not want to install a manager, specify the -exclude-manager option.

4.2.5. Creating Ceph Manager

The Manager daemon runs alongside the monitors, providing an interface for monitoring the cluster. Since the Ceph luminous release the ceph-mgr
[Ceph Manager http://docs.ceph.com/docs/luminous/mgr/]
daemon is required. During monitor installation the ceph manager will be installed as well.

Note It is recommended to install the Ceph Manager on the monitor nodes. For high availability install more then one manager.
pveceph createmgr

4.2.6. Creating Ceph OSDs

gui-ceph-osd-status.png

via GUI or via CLI as follows:

pveceph createosd /dev/sd[X]
Tip We recommend a Ceph cluster size, starting with 12 OSDs, distributed evenly among your, at least three nodes (4 OSDs on each node).

If the disk was used before (eg. ZFS/RAID/OSD), to remove partition table, boot sector and any OSD leftover the following commands should be sufficient.

dd if=/dev/zero of=/dev/sd[X] bs=1M count=200
ceph-disk zap /dev/sd[X]
Warning The above commands will destroy data on the disk!
Ceph Bluestore

Starting with the Ceph Kraken release, a new Ceph OSD storage type was introduced, the so called Bluestore
[Ceph Bluestore http://ceph.com/community/new-luminous-bluestore/]
. This is the default when creating OSDs in Ceph luminous.

pveceph createosd /dev/sd[X]
Note In order to select a disk in the GUI, to be more failsafe, the disk needs to have a GPT
[GPT partition table https://en.wikipedia.org/wiki/GUID_Partition_Table]
partition table. You can create this with gdisk /dev/sd(x). If there is no GPT, you cannot select the disk as DB/WAL.

If you want to use a separate DB/WAL device for your OSDs, you can specify it through the -journal_dev option. The WAL is placed with the DB, if not specified separately.

pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y]
Note The DB stores BlueStore’s internal metadata and the WAL is BlueStore’s internal journal or write-ahead log. It is recommended to use a fast SSDs or NVRAM for better performance.
Ceph Filestore

Till Ceph luminous, Filestore was used as storage type for Ceph OSDs. It can still be used and might give better performance in small setups, when backed by a NVMe SSD or similar.

pveceph createosd /dev/sd[X] -bluestore 0
Note In order to select a disk in the GUI, the disk needs to have a GPT
[GPT]
partition table. You can create this with gdisk /dev/sd(x). If there is no GPT, you cannot select the disk as journal. Currently the journal size is fixed to 5 GB.

If you want to use a dedicated SSD journal disk:

pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y] -bluestore 0

Example: Use /dev/sdf as data disk (4TB) and /dev/sdb is the dedicated SSD journal disk.

pveceph createosd /dev/sdf -journal_dev /dev/sdb -bluestore 0

This partitions the disk (data and journal partition), creates filesystems and starts the OSD, afterwards it is running and fully functional.

Note This command refuses to initialize disk when it detects existing data. So if you want to overwrite a disk you should remove existing data first. You can do that using: ceph-disk zap /dev/sd[X]

You can create OSDs containing both journal and data partitions or you can place the journal on a dedicated SSD. Using a SSD journal disk is highly recommended to achieve good performance.

4.2.7. Creating Ceph Pools

gui-ceph-pools.png

A pool is a logical group for storing objects. It holds Placement Groups (PG), a collection of objects.

When no options are given, we set a default of 64 PGs, a size of 3 replicas and a min_size of 2 replicas for serving objects in a degraded state.

Note The default number of PGs works for 2-6 disks. Ceph throws a "HEALTH_WARNING" if you have too few or too many PGs in your cluster.

It is advised to calculate the PG number depending on your setup, you can find the formula and the PG calculator
[PG calculator http://ceph.com/pgcalc/]
online. While PGs can be increased later on, they can never be decreased.

You can create pools through command line or on the GUI on each PVE host under Ceph → Pools.

pveceph createpool <name>

If you would like to automatically get also a storage definition for your pool, active the checkbox "Add storages" on the GUI or use the command line option --add_storages on pool creation.

Further information on Ceph pool handling can be found in the Ceph pool operation
[Ceph pool operation http://docs.ceph.com/docs/luminous/rados/operations/pools/]
manual.

4.2.8. Ceph CRUSH & device classes

The foundation of Ceph is its algorithm, Controlled Replication Under Scalable Hashing (CRUSH
[CRUSH https://ceph.com/wp-content/uploads/2016/08/weil-crush-sc06.pdf]
).

CRUSH calculates where to store to and retrieve data from, this has the advantage that no central index service is needed. CRUSH works with a map of OSDs, buckets (device locations) and rulesets (data replication) for pools.

Note Further information can be found in the Ceph documentation, under the section CRUSH map
[CRUSH map http://docs.ceph.com/docs/luminous/rados/operations/crush-map/]
.

This map can be altered to reflect different replication hierarchies. The object replicas can be separated (eg. failure domains), while maintaining the desired distribution.

A common use case is to use different classes of disks for different Ceph pools. For this reason, Ceph introduced the device classes with luminous, to accommodate the need for easy ruleset generation.

The device classes can be seen in the ceph osd tree output. These classes represent their own root bucket, which can be seen with the below command.

ceph osd crush tree --show-shadow

Example output form the above command:

ID  CLASS WEIGHT  TYPE NAME
-16  nvme 2.18307 root default~nvme
-13  nvme 0.72769     host sumi1~nvme
 12  nvme 0.72769         osd.12
-14  nvme 0.72769     host sumi2~nvme
 13  nvme 0.72769         osd.13
-15  nvme 0.72769     host sumi3~nvme
 14  nvme 0.72769         osd.14
 -1       7.70544 root default
 -3       2.56848     host sumi1
 12  nvme 0.72769         osd.12
 -5       2.56848     host sumi2
 13  nvme 0.72769         osd.13
 -7       2.56848     host sumi3
 14  nvme 0.72769         osd.14

To let a pool distribute its objects only on a specific device class, you need to create a ruleset with the specific class first.

ceph osd crush rule create-replicated <rule-name> <root> <failure-domain> <class>

<rule-name>

name of the rule, to connect with a pool (seen in GUI & CLI)

<root>

which crush root it should belong to (default ceph root "default")

<failure-domain>

at which failure-domain the objects should be distributed (usually host)

<class>

what type of OSD backing store to use (eg. nvme, ssd, hdd)

Once the rule is in the CRUSH map, you can tell a pool to use the ruleset.

ceph osd pool set <pool-name> crush_rule <rule-name>
Tip If the pool already contains objects, all of these have to be moved accordingly. Depending on your setup this may introduce a big performance hit on your cluster. As an alternative, you can create a new pool and move disks separately.

4.2.9. Ceph Client

gui-ceph-log.png

You can then configure Proxmox VE to use such pools to store VM or Container images. Simply use the GUI too add a new RBD storage (see section Ceph RADOS Block Devices (RBD)).

You also need to copy the keyring to a predefined location for a external Ceph cluster. If Ceph is installed on the Proxmox nodes itself, then this will be done automatically.

Note The file name needs to be <storage_id> + `.keyring - <storage_id> is the expression after rbd: in /etc/pve/storage.cfg which is my-ceph-storage in the following example:
mkdir /etc/pve/priv/ceph
cp /etc/ceph/ceph.client.admin.keyring /etc/pve/priv/ceph/my-ceph-storage.keyring

5. Graphical User Interface

Proxmox VE is simple. There is no need to install a separate management tool, and everything can be done through your web browser (Latest Firefox or Google Chrome is preferred). A built-in HTML5 console is used to access the guest console. As an alternative, SPICE can be used.

Because we use the Proxmox cluster file system (pmxcfs), you can connect to any node to manage the entire cluster. Each node can manage the entire cluster. There is no need for a dedicated manager node.

You can use the web-based administration interface with any modern browser. When Proxmox VE detects that you are connecting from a mobile device, you are redirected to a simpler, touch-based user interface.

The web interface can be reached via https://youripaddress:8006 (default login is: root, and the password is specified during the installation process).

5.1. Features

  • Seamless integration and management of Proxmox VE clusters

  • AJAX technologies for dynamic updates of resources

  • Secure access to all Virtual Machines and Containers via SSL encryption (https)

  • Fast search-driven interface, capable of handling hundreds and probably thousands of VMs

  • Secure HTML5 console or SPICE

  • Role based permission management for all objects (VMs, storages, nodes, etc.)

  • Support for multiple authentication sources (e.g. local, MS ADS, LDAP, …)

  • Two-Factor Authentication (OATH, Yubikey)

  • Based on ExtJS 6.x JavaScript framework

5.2. Login

gui-login-window.png

When you connect to the server, you will first see the login window. Proxmox VE supports various authentication backends (Realm), and you can select the language here. The GUI is translated to more than 20 languages.

Note You can save the user name on the client side by selection the checkbox at the bottom. This saves some typing when you login next time.

5.3. GUI Overview

gui-datacenter-summary.png

The Proxmox VE user interface consists of four regions.

Header

On top. Shows status information and contains buttons for most important actions.

Resource Tree

At the left side. A navigation tree where you can select specific objects.

Content Panel

Center region. Selected objects displays configuration options and status here.

Log Panel

At the bottom. Displays log entries for recent tasks. You can double-click on those log entries to get more details, or to abort a running task.

Note You can shrink and expand the size of the resource tree and log panel, or completely hide the log panel. This can be helpful when you work on small displays and want more space to view other content.

5.3.1. Header

On the top left side, the first thing you see is the Proxmox logo. Next to it is the current running version of Proxmox VE. In the search bar nearside you can search for specific objects (VMs, containers, nodes, …). This is sometimes faster than selecting an object in the resource tree.

gui-my-settings.png

To the right of the search bar we see the identity (login name). The gear symbol is a button opening the My Settings dialog. There you can customize some client side user interface setting (reset the saved login name, reset saved layout).

The rightmost part of the header contains four buttons:

Help

Opens a new browser window showing the reference documentation.

Create VM

Opens the virtual machine creation wizard.

Create CT

Open the container creation wizard.

Logout

Logout, and show the login dialog again.

5.3.2. Resource Tree

This is the main navigation tree. On top of the tree you can select some predefined views, which changes the structure of the tree below. The default view is Server View, and it shows the following object types:

Datacenter

Contains cluster wide setting (relevant for all nodes).

Node

Represents the hosts inside a cluster, where the guests runs.

Guest

VMs, Containers and Templates.

Storage

Data Storage.

Pool

It is possible to group guests using a pool to simplify management.

The following view types are available:

Server View

Shows all kind of objects, grouped by nodes.

Folder View

Shows all kind of objects, grouped by object type.

Storage View

Only show storage objects, grouped by nodes.

Pool View

Show VMs and Containers, grouped by pool.

5.3.3. Log Panel

The main purpose of the log panel is to show you what is currently going on in your cluster. Actions like creating an new VM are executed in background, and we call such background job a task.

Any output from such task is saved into a separate log file. You can view that log by simply double-click a task log entry. It is also possible to abort a running task there.

Please note that we display most recent tasks from all cluster nodes here. So you can see when somebody else is working on another cluster node in real-time.

Note We remove older and finished task from the log panel to keep that list short. But you can still find those tasks in the Task History within the node panel.

Some short running actions simply sends logs to all cluster members. You can see those messages in the Cluster log panel.

5.4. Content Panels

When you select something in the resource tree, the corresponding object displays configuration and status information in the content panel. The following sections give a brief overview of the functionality. Please refer to the individual chapters inside the reference documentation to get more detailed information.

5.4.1. Datacenter

gui-datacenter-search.png

On the datacenter level you can access cluster wide settings and information.

  • Search: it is possible to search anything in cluster ,this can be a node, VM, Container, Storage or a pool.

  • Summary: gives a brief overview over the cluster health.

  • Options: can show and set defaults, which apply cluster wide.

  • Storage: is the place where a storage will add/managed/removed.

  • Backup: has the capability to schedule Backups. This is cluster wide, so you do not care about where the VM/Container are on your cluster at schedule time.

  • Permissions: will manage user and group permission, LDAP, MS-AD and Two-Factor authentication can be setup here.

  • HA: will manage the Proxmox VE High-Availability

  • Firewall: on this level the Proxmox Firewall works cluster wide and makes templates which are cluster wide available.

  • Support: here you get all information about your support subscription.

If you like to have more information about this see the corresponding chapter.

5.4.2. Nodes

gui-node-summary.png

All belongs of a node can be managed at this level.

  • Search: it is possible to search anything on the node, this can be a VM, Container, Storage or a pool.

  • Summary: gives a brief overview over the resource usage.

  • Shell: log you in the shell of the node.

  • System: is for configuring the network, dns and time, and also shows your syslog.

  • Updates: will upgrade the system and informs you about new packets.

  • Firewall: on this level is only for this node.

  • Disk: gives you an brief overview about you physical hard drives and how they are used.

  • Ceph: is only used if you have installed a Ceph sever on you host. Then you can manage your Ceph cluster and see the status of it here.

  • Task History: here all past task are shown.

  • Subscription: here you can upload you subscription key and get a system overview in case of a support case.

5.4.3. Guests

gui-qemu-summary.png

There are two differed kinds of VM types and both types can be converted to a template. One of them are Kernel-based Virtual Machine (KVM) and the other one are Linux Containers (LXC). General the navigation are the same only some option are different.

In the main management center the VM navigation begin if a VM is selected in the left tree.

The top header contains important VM operation commands like Start, Shutdown, Reset, Remove, Migrate, Console and Help. Some of them have hidden buttons like Shutdown has Stop and Console contains the different console types SPICE, noVNC and xterm.js.

On the right side the content switch white the focus of the option.

On the left side. All available options are listed one below the other.

  • Summary: gives a brief overview over the VM activity.

  • Console: an interactive console to your VM.

  • (KVM)Hardware: shows and set the Hardware of the KVM VM.

  • (LXC)Resources: defines the LXC Hardware opportunities.

  • (LXC)Network: the LXC Network settings.

  • (LXC)DNS: the LXC DNS settings.

  • Options: all VM options can be set here, this distinguishes between KVM and LXC.

  • Task History: here all previous task from this VM will be shown.

  • (KVM) Monitor: is the interactive communication interface to the KVM process.

  • Backup: shows the available backups from this VM and also create a backupset.

  • Replication: shows the replication jobs for this VM and allows to create new jobs.

  • Snapshots: manage VM snapshots.

  • Firewall: manage the firewall on VM level.

  • Permissions: manage the user permission for this VM.

5.4.4. Storage

gui-storage-summary-local.png

In this view we have a two partition split view. On the left side we have the storage options and on the right side the content of the selected option will shown.

  • Summary: show you important information about your storage like Usage, Type, Content, Active and Enabled.

  • Content: Here all contend will listed grouped by content.

  • Permissions: manage the user permission for this storage.

5.4.5. Pools

gui-pool-summary-development.png

In this view we have a two partition split view. On the left side we have the logical pool options and on the right side the content of the selected option will shown.

  • Summary: show the description of the pool.

  • Members: Here all members of this pool will listed and can be managed.

  • Permissions: manage the user permission for this pool.

6. Cluster Manager

The Proxmox VE cluster manager pvecm is a tool to create a group of physical servers. Such a group is called a cluster. We use the Corosync Cluster Engine for reliable group communication, and such clusters can consist of up to 32 physical nodes (probably more, dependent on network latency).

pvecm can be used to create a new cluster, join nodes to a cluster, leave the cluster, get status information and do various other cluster related tasks. The Proxmox Cluster File System (“pmxcfs”) is used to transparently distribute the cluster configuration to all cluster nodes.

Grouping nodes into a cluster has the following advantages:

  • Centralized, web based management

  • Multi-master clusters: each node can do all management task

  • pmxcfs: database-driven file system for storing configuration files, replicated in real-time on all nodes using corosync.

  • Easy migration of virtual machines and containers between physical hosts

  • Fast deployment

  • Cluster-wide services like firewall and HA

6.1. Requirements

  • All nodes must be in the same network as corosync uses IP Multicast to communicate between nodes (also see Corosync Cluster Engine). Corosync uses UDP ports 5404 and 5405 for cluster communication.

    Note Some switches do not support IP multicast by default and must be manually enabled first.
  • Date and time have to be synchronized.

  • SSH tunnel on TCP port 22 between nodes is used.

  • If you are interested in High Availability, you need to have at least three nodes for reliable quorum. All nodes should have the same version.

  • We recommend a dedicated NIC for the cluster traffic, especially if you use shared storage.

Note It is not possible to mix Proxmox VE 3.x and earlier with Proxmox VE 4.0 cluster nodes.

6.2. Preparing Nodes

First, install Proxmox VE on all nodes. Make sure that each node is installed with the final hostname and IP configuration. Changing the hostname and IP is not possible after cluster creation.

Currently the cluster creation has to be done on the console, so you need to login via ssh.

6.3. Create the Cluster

Login via ssh to the first Proxmox VE node. Use a unique name for your cluster. This name cannot be changed later.

hp1# pvecm create YOUR-CLUSTER-NAME
Caution The cluster name is used to compute the default multicast address. Please use unique cluster names if you run more than one cluster inside your network.

To check the state of your cluster use:

hp1# pvecm status

6.3.1. Multiple Clusters In Same Network

It is possible to create multiple clusters in the same physical or logical network. Each cluster must have a unique name, which is used to generate the cluster’s multicast group address. As long as no duplicate cluster names are configured in one network segment, the different clusters won’t interfere with each other.

If multiple clusters operate in a single network it may be beneficial to setup an IGMP querier and enable IGMP Snooping in said network. This may reduce the load of the network significantly because multicast packets are only delivered to endpoints of the respective member nodes.

6.4. Adding Nodes to the Cluster

Login via ssh to the node you want to add.

hp2# pvecm add IP-ADDRESS-CLUSTER

For IP-ADDRESS-CLUSTER use the IP from an existing cluster node.

Caution A new node cannot hold any VMs, because you would get conflicts about identical VM IDs. Also, all existing configuration in /etc/pve is overwritten when you join a new node to the cluster. To workaround, use vzdump to backup and restore to a different VMID after adding the node to the cluster.

To check the state of cluster:

# pvecm status
Cluster status after adding 4 nodes
hp2# pvecm status
Quorum information
~~~~~~~~~~~~~~~~~~
Date:             Mon Apr 20 12:30:13 2015
Quorum provider:  corosync_votequorum
Nodes:            4
Node ID:          0x00000001
Ring ID:          1928
Quorate:          Yes

Votequorum information
~~~~~~~~~~~~~~~~~~~~~~
Expected votes:   4
Highest expected: 4
Total votes:      4
Quorum:           2
Flags:            Quorate

Membership information
~~~~~~~~~~~~~~~~~~~~~~
    Nodeid      Votes Name
0x00000001          1 192.168.15.91
0x00000002          1 192.168.15.92 (local)
0x00000003          1 192.168.15.93
0x00000004          1 192.168.15.94

If you only want the list of all nodes use:

# pvecm nodes
List nodes in a cluster
hp2# pvecm nodes

Membership information
~~~~~~~~~~~~~~~~~~~~~~
    Nodeid      Votes Name
         1          1 hp1
         2          1 hp2 (local)
         3          1 hp3
         4          1 hp4

6.4.1. Adding Nodes With Separated Cluster Network

When adding a node to a cluster with a separated cluster network you need to use the ringX_addr parameters to set the nodes address on those networks:

pvecm add IP-ADDRESS-CLUSTER -ring0_addr IP-ADDRESS-RING0

If you want to use the Redundant Ring Protocol you will also want to pass the ring1_addr parameter.

6.5. Remove a Cluster Node

Caution Read carefully the procedure before proceeding, as it could not be what you want or need.

Move all virtual machines from the node. Make sure you have no local data or backups you want to keep, or save them accordingly. In the following example we will remove the node hp4 from the cluster.

Log in to a different cluster node (not hp4), and issue a pvecm nodes command to identify the node ID to remove:

hp1# pvecm nodes

Membership information
~~~~~~~~~~~~~~~~~~~~~~
    Nodeid      Votes Name
         1          1 hp1 (local)
         2          1 hp2
         3          1 hp3
         4          1 hp4

At this point you must power off hp4 and make sure that it will not power on again (in the network) as it is.

Important As said above, it is critical to power off the node before removal, and make sure that it will never power on again (in the existing cluster network) as it is. If you power on the node as it is, your cluster will be screwed up and it could be difficult to restore a clean cluster state.

After powering off the node hp4, we can safely remove it from the cluster.

hp1# pvecm delnode hp4

If the operation succeeds no output is returned, just check the node list again with pvecm nodes or pvecm status. You should see something like:

hp1# pvecm status

Quorum information
~~~~~~~~~~~~~~~~~~
Date:             Mon Apr 20 12:44:28 2015
Quorum provider:  corosync_votequorum
Nodes:            3
Node ID:          0x00000001
Ring ID:          1992
Quorate:          Yes

Votequorum information
~~~~~~~~~~~~~~~~~~~~~~
Expected votes:   3
Highest expected: 3
Total votes:      3
Quorum:           3
Flags:            Quorate

Membership information
~~~~~~~~~~~~~~~~~~~~~~
    Nodeid      Votes Name
0x00000001          1 192.168.15.90 (local)
0x00000002          1 192.168.15.91
0x00000003          1 192.168.15.92

If, for whatever reason, you want that this server joins the same cluster again, you have to

  • reinstall Proxmox VE on it from scratch

  • then join it, as explained in the previous section.

6.5.1. Separate A Node Without Reinstalling

Caution This is not the recommended method, proceed with caution. Use the above mentioned method if you’re unsure.

You can also separate a node from a cluster without reinstalling it from scratch. But after removing the node from the cluster it will still have access to the shared storages! This must be resolved before you start removing the node from the cluster. A Proxmox VE cluster cannot share the exact same storage with another cluster, as storage locking doesn’t work over cluster boundary. Further, it may also lead to VMID conflicts.

Its suggested that you create a new storage where only the node which you want to separate has access. This can be an new export on your NFS or a new Ceph pool, to name a few examples. Its just important that the exact same storage does not gets accessed by multiple clusters. After setting this storage up move all data from the node and its VMs to it. Then you are ready to separate the node from the cluster.

Warning Ensure all shared resources are cleanly separated! You will run into conflicts and problems else.

First stop the corosync and the pve-cluster services on the node:

systemctl stop pve-cluster
systemctl stop corosync

Start the cluster filesystem again in local mode:

pmxcfs -l

Delete the corosync configuration files:

rm /etc/pve/corosync.conf
rm /etc/corosync/*

You can now start the filesystem again as normal service:

killall pmxcfs
systemctl start pve-cluster

The node is now separated from the cluster. You can deleted it from a remaining node of the cluster with:

pvecm delnode oldnode

If the command failed, because the remaining node in the cluster lost quorum when the now separate node exited, you may set the expected votes to 1 as a workaround:

pvecm expected 1

And the repeat the pvecm delnode command.

Now switch back to the separated node, here delete all remaining files left from the old cluster. This ensures that the node can be added to another cluster again without problems.

rm /var/lib/corosync/*

As the configuration files from the other nodes are still in the cluster filesystem you may want to clean those up too. Remove simply the whole directory recursive from /etc/pve/nodes/NODENAME, but check three times that you used the correct one before deleting it.

Caution The nodes SSH keys are still in the authorized_key file, this means the nodes can still connect to each other with public key authentication. This should be fixed by removing the respective keys from the /etc/pve/priv/authorized_keys file.

6.6. Quorum

Proxmox VE use a quorum-based technique to provide a consistent state among all cluster nodes.

A quorum is the minimum number of votes that a distributed transaction has to obtain in order to be allowed to perform an operation in a distributed system.

Quorum (distributed computing)
— from Wikipedia

In case of network partitioning, state changes requires that a majority of nodes are online. The cluster switches to read-only mode if it loses quorum.

Note Proxmox VE assigns a single vote to each node by default.

6.7. Cluster Network

The cluster network is the core of a cluster. All messages sent over it have to be delivered reliable to all nodes in their respective order. In Proxmox VE this part is done by corosync, an implementation of a high performance low overhead high availability development toolkit. It serves our decentralized configuration file system (pmxcfs).

6.7.1. Network Requirements

This needs a reliable network with latencies under 2 milliseconds (LAN performance) to work properly. While corosync can also use unicast for communication between nodes its highly recommended to have a multicast capable network. The network should not be used heavily by other members, ideally corosync runs on its own network. never share it with network where storage communicates too.

Before setting up a cluster it is good practice to check if the network is fit for that purpose.

  • Ensure that all nodes are in the same subnet. This must only be true for the network interfaces used for cluster communication (corosync).

  • Ensure all nodes can reach each other over those interfaces, using ping is enough for a basic test.

  • Ensure that multicast works in general and a high package rates. This can be done with the omping tool. The final "%loss" number should be < 1%.

    omping -c 10000 -i 0.001 -F -q NODE1-IP NODE2-IP ...
  • Ensure that multicast communication works over an extended period of time. This uncovers problems where IGMP snooping is activated on the network but no multicast querier is active. This test has a duration of around 10 minutes.

    omping -c 600 -i 1 -q NODE1-IP NODE2-IP ...

Your network is not ready for clustering if any of these test fails. Recheck your network configuration. Especially switches are notorious for having multicast disabled by default or IGMP snooping enabled with no IGMP querier active.

In smaller cluster its also an option to use unicast if you really cannot get multicast to work.

6.7.2. Separate Cluster Network

When creating a cluster without any parameters the cluster network is generally shared with the Web UI and the VMs and its traffic. Depending on your setup even storage traffic may get sent over the same network. Its recommended to change that, as corosync is a time critical real time application.

Setting Up A New Network

First you have to setup a new network interface. It should be on a physical separate network. Ensure that your network fulfills the cluster network requirements.

Separate On Cluster Creation

This is possible through the ring0_addr and bindnet0_addr parameter of the pvecm create command used for creating a new cluster.

If you have setup an additional NIC with a static address on 10.10.10.1/25 and want to send and receive all cluster communication over this interface you would execute:

pvecm create test --ring0_addr 10.10.10.1 --bindnet0_addr 10.10.10.0

To check if everything is working properly execute:

systemctl status corosync

Afterwards, proceed as descripted in the section to add nodes with a separated cluster network.

Separate After Cluster Creation

You can do this also if you have already created a cluster and want to switch its communication to another network, without rebuilding the whole cluster. This change may lead to short durations of quorum loss in the cluster, as nodes have to restart corosync and come up one after the other on the new network.

Check how to edit the corosync.conf file first. The open it and you should see a file similar to:

logging {
  debug: off
  to_syslog: yes
}

nodelist {

  node {
    name: due
    nodeid: 2
    quorum_votes: 1
    ring0_addr: due
  }

  node {
    name: tre
    nodeid: 3
    quorum_votes: 1
    ring0_addr: tre
  }

  node {
    name: uno
    nodeid: 1
    quorum_votes: 1
    ring0_addr: uno
  }

}

quorum {
  provider: corosync_votequorum
}

totem {
  cluster_name: thomas-testcluster
  config_version: 3
  ip_version: ipv4
  secauth: on
  version: 2
  interface {
    bindnetaddr: 192.168.30.50
    ringnumber: 0
  }

}

The first you want to do is add the name properties in the node entries if you do not see them already. Those must match the node name.

Then replace the address from the ring0_addr properties with the new addresses. You may use plain IP addresses or also hostnames here. If you use hostnames ensure that they are resolvable from all nodes.

In my example I want to switch my cluster communication to the 10.10.10.1/25 network. So I replace all ring0_addr respectively. I also set the bindnetaddr in the totem section of the config to an address of the new network. It can be any address from the subnet configured on the new network interface.

After you increased the config_version property the new configuration file should look like:

logging {
  debug: off
  to_syslog: yes
}

nodelist {

  node {
    name: due
    nodeid: 2
    quorum_votes: 1
    ring0_addr: 10.10.10.2
  }

  node {
    name: tre
    nodeid: 3
    quorum_votes: 1
    ring0_addr: 10.10.10.3
  }

  node {
    name: uno
    nodeid: 1
    quorum_votes: 1
    ring0_addr: 10.10.10.1
  }

}

quorum {
  provider: corosync_votequorum
}

totem {
  cluster_name: thomas-testcluster
  config_version: 4
  ip_version: ipv4
  secauth: on
  version: 2
  interface {
    bindnetaddr: 10.10.10.1
    ringnumber: 0
  }

}

Now after a final check whether all changed information is correct we save it and see again the edit corosync.conf file section to learn how to bring it in effect.

As our change cannot be enforced live from corosync we have to do an restart.

On a single node execute:

systemctl restart corosync

Now check if everything is fine:

systemctl status corosync

If corosync runs again correct restart corosync also on all other nodes. They will then join the cluster membership one by one on the new network.

6.7.3. Redundant Ring Protocol

To avoid a single point of failure you should implement counter measurements. This can be on the hardware and operating system level through network bonding.

Corosync itself offers also a possibility to add redundancy through the so called Redundant Ring Protocol. This protocol allows running a second totem ring on another network, this network should be physically separated from the other rings network to actually increase availability.

6.7.4. RRP On Cluster Creation

The pvecm create command provides the additional parameters bindnetX_addr, ringX_addr and rrp_mode, can be used for RRP configuration.

Note See the glossary if you do not know what each parameter means.

So if you have two networks, one on the 10.10.10.1/24 and the other on the 10.10.20.1/24 subnet you would execute:

pvecm create CLUSTERNAME -bindnet0_addr 10.10.10.1 -ring0_addr 10.10.10.1 \
-bindnet1_addr 10.10.20.1 -ring1_addr 10.10.20.1

6.7.5. RRP On Existing Clusters

You will take similar steps as described in separating the cluster network to enable RRP on an already running cluster. The single difference is, that you will add ring1 and use it instead of ring0.

First add a new interface subsection in the totem section, set its ringnumber property to 1. Set the interfaces bindnetaddr property to an address of the subnet you have configured for your new ring. Further set the rrp_mode to passive, this is the only stable mode.

Then add to each node entry in the nodelist section its new ring1_addr property with the nodes additional ring address.

So if you have two networks, one on the 10.10.10.1/24 and the other on the 10.10.20.1/24 subnet, the final configuration file should look like:

totem {
  cluster_name: tweak
  config_version: 9
  ip_version: ipv4
  rrp_mode: passive
  secauth: on
  version: 2
  interface {
    bindnetaddr: 10.10.10.1
    ringnumber: 0
  }
  interface {
    bindnetaddr: 10.10.20.1
    ringnumber: 1
  }
}

nodelist {
  node {
    name: pvecm1
    nodeid: 1
    quorum_votes: 1
    ring0_addr: 10.10.10.1
    ring1_addr: 10.10.20.1
  }

 node {
    name: pvecm2
    nodeid: 2
    quorum_votes: 1
    ring0_addr: 10.10.10.2
    ring1_addr: 10.10.20.2
  }

  [...] # other cluster nodes here
}

[...] # other remaining config sections here

Bring it in effect like described in the edit the corosync.conf file section.

This is a change which cannot take live in effect and needs at least a restart of corosync. Recommended is a restart of the whole cluster.

If you cannot reboot the whole cluster ensure no High Availability services are configured and the stop the corosync service on all nodes. After corosync is stopped on all nodes start it one after the other again.

6.8. Corosync Configuration

The /etc/pve/corosync.conf file plays a central role in Proxmox VE cluster. It controls the cluster member ship and its network. For reading more about it check the corosync.conf man page:

man corosync.conf

For node membership you should always use the pvecm tool provided by Proxmox VE. You may have to edit the configuration file manually for other changes. Here are a few best practice tips for doing this.

6.8.1. Edit corosync.conf

Editing the corosync.conf file can be not always straight forward. There are two on each cluster, one in /etc/pve/corosync.conf and the other in /etc/corosync/corosync.conf. Editing the one in our cluster file system will propagate the changes to the local one, but not vice versa.

The configuration will get updated automatically as soon as the file changes. This means changes which can be integrated in a running corosync will take instantly effect. So you should always make a copy and edit that instead, to avoid triggering some unwanted changes by an in between safe.

cp /etc/pve/corosync.conf /etc/pve/corosync.conf.new

Then open the Config file with your favorite editor, nano and vim.tiny are preinstalled on Proxmox VE for example.

Note Always increment the config_version number on configuration changes, omitting this can lead to problems.

After making the necessary changes create another copy of the current working configuration file. This serves as a backup if the new configuration fails to apply or makes problems in other ways.

cp /etc/pve/corosync.conf /etc/pve/corosync.conf.bak

Then move the new configuration file over the old one:

mv /etc/pve/corosync.conf.new /etc/pve/corosync.conf

You may check with the commands

systemctl status corosync
journalctl -b -u corosync

If the change could applied automatically. If not you may have to restart the corosync service via:

systemctl restart corosync

On errors check the troubleshooting section below.

6.8.2. Troubleshooting

Issue: quorum.expected_votes must be configured

When corosync starts to fail and you get the following message in the system log:

[...]
corosync[1647]:  [QUORUM] Quorum provider: corosync_votequorum failed to initialize.
corosync[1647]:  [SERV  ] Service engine 'corosync_quorum' failed to load for reason
    'configuration error: nodelist or quorum.expected_votes must be configured!'
[...]

It means that the hostname you set for corosync ringX_addr in the configuration could not be resolved.

Write Configuration When Not Quorate

If you need to change /etc/pve/corosync.conf on an node with no quorum, and you know what you do, use:

pvecm expected 1

This sets the expected vote count to 1 and makes the cluster quorate. You can now fix your configuration, or revert it back to the last working backup.

This is not enough if corosync cannot start anymore. Here its best to edit the local copy of the corosync configuration in /etc/corosync/corosync.conf so that corosync can start again. Ensure that on all nodes this configuration has the same content to avoid split brains. If you are not sure what went wrong it’s best to ask the Proxmox Community to help you.

6.8.3. Corosync Configuration Glossary

ringX_addr

This names the different ring addresses for the corosync totem rings used for the cluster communication.

bindnetaddr

Defines to which interface the ring should bind to. It may be any address of the subnet configured on the interface we want to use. In general its the recommended to just use an address a node uses on this interface.

rrp_mode

Specifies the mode of the redundant ring protocol and may be passive, active or none. Note that use of active is highly experimental and not official supported. Passive is the preferred mode, it may double the cluster communication throughput and increases availability.

6.9. Cluster Cold Start

It is obvious that a cluster is not quorate when all nodes are offline. This is a common case after a power failure.

Note It is always a good idea to use an uninterruptible power supply (“UPS”, also called “battery backup”) to avoid this state, especially if you want HA.

On node startup, the pve-guests service is started and waits for quorum. Once quorate, it starts all guests which have the onboot flag set.

When you turn on nodes, or when power comes back after power failure, it is likely that some nodes boots faster than others. Please keep in mind that guest startup is delayed until you reach quorum.

6.10. Guest Migration

Migrating virtual guests to other nodes is a useful feature in a cluster. There are settings to control the behavior of such migrations. This can be done via the configuration file datacenter.cfg or for a specific migration via API or command line parameters.

It makes a difference if a Guest is online or offline, or if it has local resources (like a local disk).

For Details about Virtual Machine Migration see the QEMU/KVM Migration Chapter

For Details about Container Migration see the Container Migration Chapter

6.10.1. Migration Type

The migration type defines if the migration data should be sent over an encrypted (secure) channel or an unencrypted (insecure) one. Setting the migration type to insecure means that the RAM content of a virtual guest gets also transferred unencrypted, which can lead to information disclosure of critical data from inside the guest (for example passwords or encryption keys).

Therefore, we strongly recommend using the secure channel if you do not have full control over the network and can not guarantee that no one is eavesdropping to it.

Note Storage migration does not follow this setting. Currently, it always sends the storage content over a secure channel.

Encryption requires a lot of computing power, so this setting is often changed to "unsafe" to achieve better performance. The impact on modern systems is lower because they implement AES encryption in hardware. The performance impact is particularly evident in fast networks where you can transfer 10 Gbps or more.

6.10.2. Migration Network

By default, Proxmox VE uses the network in which cluster communication takes place to send the migration traffic. This is not optimal because sensitive cluster traffic can be disrupted and this network may not have the best bandwidth available on the node.

Setting the migration network parameter allows the use of a dedicated network for the entire migration traffic. In addition to the memory, this also affects the storage traffic for offline migrations.

The migration network is set as a network in the CIDR notation. This has the advantage that you do not have to set individual IP addresses for each node. Proxmox VE can determine the real address on the destination node from the network specified in the CIDR form. To enable this, the network must be specified so that each node has one, but only one IP in the respective network.

Example

We assume that we have a three-node setup with three separate networks. One for public communication with the Internet, one for cluster communication and a very fast one, which we want to use as a dedicated network for migration.

A network configuration for such a setup might look as follows:

iface eno1 inet manual

# public network
auto vmbr0
iface vmbr0 inet static
    address 192.X.Y.57
    netmask 255.255.250.0
    gateway 192.X.Y.1
    bridge_ports eno1
    bridge_stp off
    bridge_fd 0

# cluster network
auto eno2
iface eno2 inet static
    address  10.1.1.1
    netmask  255.255.255.0

# fast network
auto eno3
iface eno3 inet static
    address  10.1.2.1
    netmask  255.255.255.0

Here, we will use the network 10.1.2.0/24 as a migration network. For a single migration, you can do this using the migration_network parameter of the command line tool:

# qm migrate 106 tre --online --migration_network 10.1.2.0/24

To configure this as the default network for all migrations in the cluster, set the migration property of the /etc/pve/datacenter.cfg file:

# use dedicated migration network
migration: secure,network=10.1.2.0/24
Note The migration type must always be set when the migration network gets set in /etc/pve/datacenter.cfg.

7. Proxmox Cluster File System (pmxcfs)

The Proxmox Cluster file system (“pmxcfs”) is a database-driven file system for storing configuration files, replicated in real time to all cluster nodes using corosync. We use this to store all PVE related configuration files.

Although the file system stores all data inside a persistent database on disk, a copy of the data resides in RAM. That imposes restriction on the maximum size, which is currently 30MB. This is still enough to store the configuration of several thousand virtual machines.

This system provides the following advantages:

  • seamless replication of all configuration to all nodes in real time

  • provides strong consistency checks to avoid duplicate VM IDs

  • read-only when a node loses quorum

  • automatic updates of the corosync cluster configuration to all nodes

  • includes a distributed locking mechanism

7.1. POSIX Compatibility

The file system is based on FUSE, so the behavior is POSIX like. But some feature are simply not implemented, because we do not need them:

  • you can just generate normal files and directories, but no symbolic links, …

  • you can’t rename non-empty directories (because this makes it easier to guarantee that VMIDs are unique).

  • you can’t change file permissions (permissions are based on path)

  • O_EXCL creates were not atomic (like old NFS)

  • O_TRUNC creates are not atomic (FUSE restriction)

7.2. File Access Rights

All files and directories are owned by user root and have group www-data. Only root has write permissions, but group www-data can read most files. Files below the following paths:

/etc/pve/priv/
/etc/pve/nodes/${NAME}/priv/

are only accessible by root.

7.3. Technology

We use the Corosync Cluster Engine for cluster communication, and SQlite for the database file. The file system is implemented in user space using FUSE.

7.4. File System Layout

The file system is mounted at:

/etc/pve

7.4.1. Files

corosync.conf

Corosync cluster configuration file (previous to Proxmox VE 4.x this file was called cluster.conf)

storage.cfg

Proxmox VE storage configuration

datacenter.cfg

Proxmox VE datacenter wide configuration (keyboard layout, proxy, …)

user.cfg

Proxmox VE access control configuration (users/groups/…)

domains.cfg

Proxmox VE authentication domains

status.cfg

Proxmox VE external metrics server configuration

authkey.pub

Public key used by ticket system

pve-root-ca.pem

Public certificate of cluster CA

priv/shadow.cfg

Shadow password file

priv/authkey.key

Private key used by ticket system

priv/pve-root-ca.key

Private key of cluster CA

nodes/<NAME>/pve-ssl.pem

Public SSL certificate for web server (signed by cluster CA)

nodes/<NAME>/pve-ssl.key

Private SSL key for pve-ssl.pem

nodes/<NAME>/pveproxy-ssl.pem

Public SSL certificate (chain) for web server (optional override for pve-ssl.pem)

nodes/<NAME>/pveproxy-ssl.key

Private SSL key for pveproxy-ssl.pem (optional)

nodes/<NAME>/qemu-server/<VMID>.conf

VM configuration data for KVM VMs

nodes/<NAME>/lxc/<VMID>.conf

VM configuration data for LXC containers

firewall/cluster.fw

Firewall configuration applied to all nodes

firewall/<NAME>.fw

Firewall configuration for individual nodes

firewall/<VMID>.fw

Firewall configuration for VMs and Containers

local

nodes/<LOCAL_HOST_NAME>

qemu-server

nodes/<LOCAL_HOST_NAME>/qemu-server/

lxc

nodes/<LOCAL_HOST_NAME>/lxc/

7.4.3. Special status files for debugging (JSON)

.version

File versions (to detect file modifications)

.members

Info about cluster members

.vmlist

List of all VMs

.clusterlog

Cluster log (last 50 entries)

.rrd

RRD data (most recent entries)

7.4.4. Enable/Disable debugging

You can enable verbose syslog messages with:

echo "1" >/etc/pve/.debug

And disable verbose syslog messages with:

echo "0" >/etc/pve/.debug

7.5. Recovery

If you have major problems with your Proxmox VE host, e.g. hardware issues, it could be helpful to just copy the pmxcfs database file /var/lib/pve-cluster/config.db and move it to a new Proxmox VE host. On the new host (with nothing running), you need to stop the pve-cluster service and replace the config.db file (needed permissions 0600). Second, adapt /etc/hostname and /etc/hosts according to the lost Proxmox VE host, then reboot and check. (And don’t forget your VM/CT data)

7.5.1. Remove Cluster configuration

The recommended way is to reinstall the node after you removed it from your cluster. This makes sure that all secret cluster/ssh keys and any shared configuration data is destroyed.

In some cases, you might prefer to put a node back to local mode without reinstall, which is described in Separate A Node Without Reinstalling

7.5.2. Recovering/Moving Guests from Failed Nodes

For the guest configuration files in nodes/<NAME>/qemu-server/ (VMs) and nodes/<NAME>/lxc/ (containers), Proxmox VE sees the containing node <NAME> as owner of the respective guest. This concept enables the usage of local locks instead of expensive cluster-wide locks for preventing concurrent guest configuration changes.

As a consequence, if the owning node of a guest fails (e.g., because of a power outage, fencing event, ..), a regular migration is not possible (even if all the disks are located on shared storage) because such a local lock on the (dead) owning node is unobtainable. This is not a problem for HA-managed guests, as Proxmox VE’s High Availability stack includes the necessary (cluster-wide) locking and watchdog functionality to ensure correct and automatic recovery of guests from fenced nodes.

If a non-HA-managed guest has only shared disks (and no other local resources which are only available on the failed node are configured), a manual recovery is possible by simply moving the guest configuration file from the failed node’s directory in /etc/pve/ to an alive node’s directory (which changes the logical owner or location of the guest).

For example, recovering the VM with ID 100 from a dead node1 to another node node2 works with the following command executed when logged in as root on any member node of the cluster:

mv /etc/pve/nodes/node1/qemu-server/100.conf /etc/pve/nodes/node2/
Warning Before manually recovering a guest like this, make absolutely sure that the failed source node is really powered off/fenced. Otherwise Proxmox VE’s locking principles are violated by the mv command, which can have unexpected consequences.
Warning Guest with local disks (or other local resources which are only available on the dead node) are not recoverable like this. Either wait for the failed node to rejoin the cluster or restore such guests from backups.

8. Proxmox VE Storage

The Proxmox VE storage model is very flexible. Virtual machine images can either be stored on one or several local storages, or on shared storage like NFS or iSCSI (NAS, SAN). There are no limits, and you may configure as many storage pools as you like. You can use all storage technologies available for Debian Linux.

One major benefit of storing VMs on shared storage is the ability to live-migrate running machines without any downtime, as all nodes in the cluster have direct access to VM disk images. There is no need to copy VM image data, so live migration is very fast in that case.

The storage library (package libpve-storage-perl) uses a flexible plugin system to provide a common interface to all storage types. This can be easily adopted to include further storage types in future.

8.1. Storage Types

There are basically two different classes of storage types:

Block level storage

Allows to store large raw images. It is usually not possible to store other files (ISO, backups, ..) on such storage types. Most modern block level storage implementations support snapshots and clones. RADOS, Sheepdog and GlusterFS are distributed systems, replicating storage data to different nodes.

File level storage

They allow access to a full featured (POSIX) file system. They are more flexible, and allows you to store any content type. ZFS is probably the most advanced system, and it has full support for snapshots and clones.

Table 2. Available storage types
Description PVE type Level Shared Snapshots Stable

ZFS (local)

zfspool

file

no

yes

yes

Directory

dir

file

no

no1

yes

NFS

nfs

file

yes

no1

yes

CIFS

cifs

file

yes

no1

yes

GlusterFS

glusterfs

file

yes

no1

yes

LVM

lvm

block

no2

no

yes

LVM-thin

lvmthin

block

no

yes

yes

iSCSI/kernel

iscsi

block

yes

no

yes

iSCSI/libiscsi

iscsidirect

block

yes

no

yes

Ceph/RBD

rbd

block

yes

yes

yes

Ceph/CephFS

cephfs

file

yes

yes

yes

Sheepdog

sheepdog

block

yes

yes

beta

ZFS over iSCSI

zfs

block

yes

yes

yes

1: On file based storages, snapshots are possible with the qcow2 format.

2: It is possible to use LVM on top of an iSCSI storage. That way you get a shared LVM storage.

8.1.1. Thin Provisioning

A number of storages, and the Qemu image format qcow2, support thin provisioning. With thin provisioning activated, only the blocks that the guest system actually use will be written to the storage.

Say for instance you create a VM with a 32GB hard disk, and after installing the guest system OS, the root file system of the VM contains 3 GB of data. In that case only 3GB are written to the storage, even if the guest VM sees a 32GB hard drive. In this way thin provisioning allows you to create disk images which are larger than the currently available storage blocks. You can create large disk images for your VMs, and when the need arises, add more disks to your storage without resizing the VMs' file systems.

All storage types which have the “Snapshots” feature also support thin provisioning.

Caution If a storage runs full, all guests using volumes on that storage receive IO errors. This can cause file system inconsistencies and may corrupt your data. So it is advisable to avoid over-provisioning of your storage resources, or carefully observe free space to avoid such conditions.

8.2. Storage Configuration

All Proxmox VE related storage configuration is stored within a single text file at /etc/pve/storage.cfg. As this file is within /etc/pve/, it gets automatically distributed to all cluster nodes. So all nodes share the same storage configuration.

Sharing storage configuration make perfect sense for shared storage, because the same “shared” storage is accessible from all nodes. But is also useful for local storage types. In this case such local storage is available on all nodes, but it is physically different and can have totally different content.

8.2.1. Storage Pools

Each storage pool has a <type>, and is uniquely identified by its <STORAGE_ID>. A pool configuration looks like this:

<type>: <STORAGE_ID>
        <property> <value>
        <property> <value>
        ...

The <type>: <STORAGE_ID> line starts the pool definition, which is then followed by a list of properties. Most properties have values, but some of them come with reasonable default. In that case you can omit the value.

To be more specific, take a look at the default storage configuration after installation. It contains one special local storage pool named local, which refers to the directory /var/lib/vz and is always available. The Proxmox VE installer creates additional storage entries depending on the storage type chosen at installation time.

Default storage configuration (/etc/pve/storage.cfg)
dir: local
        path /var/lib/vz
        content iso,vztmpl,backup

# default image store on LVM based installation
lvmthin: local-lvm
        thinpool data
        vgname pve
        content rootdir,images

# default image store on ZFS based installation
zfspool: local-zfs
        pool rpool/data
        sparse
        content images,rootdir

8.2.2. Common Storage Properties

A few storage properties are common among different storage types.

nodes

List of cluster node names where this storage is usable/accessible. One can use this property to restrict storage access to a limited set of nodes.

content

A storage can support several content types, for example virtual disk images, cdrom iso images, container templates or container root directories. Not all storage types support all content types. One can set this property to select for what this storage is used for.

images

KVM-Qemu VM images.

rootdir

Allow to store container data.

vztmpl

Container templates.

backup

Backup files (vzdump).

iso

ISO images

shared

Mark storage as shared.

disable

You can use this flag to disable the storage completely.

maxfiles

Maximum number of backup files per VM. Use 0 for unlimited.

format

Default image format (raw|qcow2|vmdk)

Warning It is not advisable to use the same storage pool on different Proxmox VE clusters. Some storage operation need exclusive access to the storage, so proper locking is required. While this is implemented within a cluster, it does not work between different clusters.

8.3. Volumes

We use a special notation to address storage data. When you allocate data from a storage pool, it returns such a volume identifier. A volume is identified by the <STORAGE_ID>, followed by a storage type dependent volume name, separated by colon. A valid <VOLUME_ID> looks like:

local:230/example-image.raw
local:iso/debian-501-amd64-netinst.iso
local:vztmpl/debian-5.0-joomla_1.5.9-1_i386.tar.gz
iscsi-storage:0.0.2.scsi-14f504e46494c4500494b5042546d2d646744372d31616d61

To get the file system path for a <VOLUME_ID> use:

pvesm path <VOLUME_ID>

8.3.1. Volume Ownership

There exists an ownership relation for image type volumes. Each such volume is owned by a VM or Container. For example volume local:230/example-image.raw is owned by VM 230. Most storage backends encodes this ownership information into the volume name.

When you remove a VM or Container, the system also removes all associated volumes which are owned by that VM or Container.

8.4. Using the Command Line Interface

It is recommended to familiarize yourself with the concept behind storage pools and volume identifiers, but in real life, you are not forced to do any of those low level operations on the command line. Normally, allocation and removal of volumes is done by the VM and Container management tools.

Nevertheless, there is a command line tool called pvesm (“Proxmox VE Storage Manager”), which is able to perform common storage management tasks.

8.4.1. Examples

Add storage pools

pvesm add <TYPE> <STORAGE_ID> <OPTIONS>
pvesm add dir <STORAGE_ID> --path <PATH>
pvesm add nfs <STORAGE_ID> --path <PATH> --server <SERVER> --export <EXPORT>
pvesm add lvm <STORAGE_ID> --vgname <VGNAME>
pvesm add iscsi <STORAGE_ID> --portal <HOST[:PORT]> --target <TARGET>

Disable storage pools

pvesm set <STORAGE_ID> --disable 1

Enable storage pools

pvesm set <STORAGE_ID> --disable 0

Change/set storage options

pvesm set <STORAGE_ID> <OPTIONS>
pvesm set <STORAGE_ID> --shared 1
pvesm set local --format qcow2
pvesm set <STORAGE_ID> --content iso

Remove storage pools. This does not delete any data, and does not disconnect or unmount anything. It just removes the storage configuration.

pvesm remove <STORAGE_ID>

Allocate volumes

pvesm alloc <STORAGE_ID> <VMID> <name> <size> [--format <raw|qcow2>]

Allocate a 4G volume in local storage. The name is auto-generated if you pass an empty string as <name>

pvesm alloc local <VMID> '' 4G

Free volumes

pvesm free <VOLUME_ID>
Warning This really destroys all volume data.

List storage status

pvesm status

List storage contents

pvesm list <STORAGE_ID> [--vmid <VMID>]

List volumes allocated by VMID

pvesm list <STORAGE_ID> --vmid <VMID>

List iso images

pvesm list <STORAGE_ID> --iso

List container templates

pvesm list <STORAGE_ID> --vztmpl

Show file system path for a volume

pvesm path <VOLUME_ID>

8.5. Directory Backend

Storage pool type: dir

Proxmox VE can use local directories or locally mounted shares for storage. A directory is a file level storage, so you can store any content type like virtual disk images, containers, templates, ISO images or backup files.

Note You can mount additional storages via standard linux /etc/fstab, and then define a directory storage for that mount point. This way you can use any file system supported by Linux.

This backend assumes that the underlying directory is POSIX compatible, but nothing else. This implies that you cannot create snapshots at the storage level. But there exists a workaround for VM images using the qcow2 file format, because that format supports snapshots internally.

Tip Some storage types do not support O_DIRECT, so you can’t use cache mode none with such storages. Simply use cache mode writeback instead.

We use a predefined directory layout to store different content types into different sub-directories. This layout is used by all file level storage backends.

Table 3. Directory layout
Content type Subdir

VM images

images/<VMID>/

ISO images

template/iso/

Container templates

template/cache/

Backup files

dump/

8.5.1. Configuration

This backend supports all common storage properties, and adds an additional property called path to specify the directory. This needs to be an absolute file system path.

Configuration Example (/etc/pve/storage.cfg)
dir: backup
        path /mnt/backup
        content backup
        maxfiles 7

Above configuration defines a storage pool called backup. That pool can be used to store up to 7 backups (maxfiles 7) per VM. The real path for the backup files is /mnt/backup/dump/....

8.5.2. File naming conventions

This backend uses a well defined naming scheme for VM images:

vm-<VMID>-<NAME>.<FORMAT>
<VMID>

This specifies the owner VM.

<NAME>

This can be an arbitrary name (ascii) without white space. The backend uses disk-[N] as default, where [N] is replaced by an integer to make the name unique.

<FORMAT>

Specifies the image format (raw|qcow2|vmdk).

When you create a VM template, all VM images are renamed to indicate that they are now read-only, and can be used as a base image for clones:

base-<VMID>-<NAME>.<FORMAT>
Note Such base images are used to generate cloned images. So it is important that those files are read-only, and never get modified. The backend changes the access mode to 0444, and sets the immutable flag (chattr +i) if the storage supports that.

8.5.3. Storage Features

As mentioned above, most file systems do not support snapshots out of the box. To workaround that problem, this backend is able to use qcow2 internal snapshot capabilities.

Same applies to clones. The backend uses the qcow2 base image feature to create clones.

Table 4. Storage features for backend dir
Content types Image formats Shared Snapshots Clones

images rootdir vztmpl iso backup

raw qcow2 vmdk subvol

no

qcow2

qcow2

8.5.4. Examples

Please use the following command to allocate a 4GB image on storage local:

# pvesm alloc local 100 vm-100-disk10.raw 4G
Formatting '/var/lib/vz/images/100/vm-100-disk10.raw', fmt=raw size=4294967296
successfully created 'local:100/vm-100-disk10.raw'
Note The image name must conform to above naming conventions.

The real file system path is shown with:

# pvesm path local:100/vm-100-disk10.raw
/var/lib/vz/images/100/vm-100-disk10.raw

And you can remove the image with:

# pvesm free local:100/vm-100-disk10.raw

8.6. NFS Backend

Storage pool type: nfs

The NFS backend is based on the directory backend, so it shares most properties. The directory layout and the file naming conventions are the same. The main advantage is that you can directly configure the NFS server properties, so the backend can mount the share automatically. There is no need to modify /etc/fstab. The backend can also test if the server is online, and provides a method to query the server for exported shares.

8.6.1. Configuration

The backend supports all common storage properties, except the shared flag, which is always set. Additionally, the following properties are used to configure the NFS server:

server

Server IP or DNS name. To avoid DNS lookup delays, it is usually preferable to use an IP address instead of a DNS name - unless you have a very reliable DNS server, or list the server in the local /etc/hosts file.

export

NFS export path (as listed by pvesm nfsscan).

You can also set NFS mount options:

path

The local mount point (defaults to /mnt/pve/<STORAGE_ID>/).

options

NFS mount options (see man nfs).

Configuration Example (/etc/pve/storage.cfg)
nfs: iso-templates
        path /mnt/pve/iso-templates
        server 10.0.0.10
        export /space/iso-templates
        options vers=3,soft
        content iso,vztmpl
Tip After an NFS request times out, NFS request are retried indefinitely by default. This can lead to unexpected hangs on the client side. For read-only content, it is worth to consider the NFS soft option, which limits the number of retries to three.

8.6.2. Storage Features

NFS does not support snapshots, but the backend uses qcow2 features to implement snapshots and cloning.

Table 5. Storage features for backend nfs
Content types Image formats Shared Snapshots Clones

images rootdir vztmpl iso backup

raw qcow2 vmdk

yes

qcow2

qcow2

8.6.3. Examples

You can get a list of exported NFS shares with:

# pvesm nfsscan <server>

8.7. CIFS Backend

Storage pool type: cifs

The CIFS backend extends the directory backend, so that no manual setup of a CIFS mount is needed. Such a storage can be added directly through the Proxmox VE API or the WebUI, with all our backend advantages, like server heartbeat check or comfortable selection of exported shares.

8.7.1. Configuration

The backend supports all common storage properties, except the shared flag, which is always set. Additionally, the following CIFS special properties are available:

server

Server IP or DNS name. Required.

Tip To avoid DNS lookup delays, it is usually preferable to use an IP address instead of a DNS name - unless you have a very reliable DNS server, or list the server in the local /etc/hosts file.
share

CIFS share to use (get available ones with pvesm cifsscan or the WebUI). Required.

username

The username for the CIFS storage. Optional, defaults to ‘guest’.

password

The user password. Optional. It will be saved in a file only readable by root (/etc/pve/priv/<STORAGE_ID>.cred).

domain

Sets the user domain (workgroup) for this storage. Optional.

smbversion

SMB protocol Version. Optional, default is 3. SMB1 is not supported due to security issues.

path

The local mount point. Optional, defaults to /mnt/pve/<STORAGE_ID>/.

Configuration Example (/etc/pve/storage.cfg)
cifs: backup
        path /mnt/pve/backup
        server 10.0.0.11
        share VMData
        content backup
        username anna
        smbversion 3

8.7.2. Storage Features

CIFS does not support snapshots on a storage level. But you may use qcow2 backing files if you still want to have snapshots and cloning features available.

Table 6. Storage features for backend cifs
Content types Image formats Shared Snapshots Clones

images rootdir vztmpl iso backup

raw qcow2 vmdk

yes

qcow2

qcow2

8.7.3. Examples

You can get a list of exported CIFS shares with:

# pvesm cifsscan <server> [--username <username>] [--password]

Then you could add this share as a storage to the whole Proxmox VE cluster with:

# pvesm add cifs <storagename> --server <server> --share <share> [--username <username>] [--password]

8.8. GlusterFS Backend

Storage pool type: glusterfs

GlusterFS is a scalable network file system. The system uses a modular design, runs on commodity hardware, and can provide a highly available enterprise storage at low costs. Such system is capable of scaling to several petabytes, and can handle thousands of clients.

Note After a node/brick crash, GlusterFS does a full rsync to make sure data is consistent. This can take a very long time with large files, so this backend is not suitable to store large VM images.

8.8.1. Configuration

The backend supports all common storage properties, and adds the following GlusterFS specific options:

server

GlusterFS volfile server IP or DNS name.

server2

Backup volfile server IP or DNS name.

volume

GlusterFS Volume.

transport

GlusterFS transport: tcp, unix or rdma

Configuration Example (/etc/pve/storage.cfg)
glusterfs: Gluster
        server 10.2.3.4
        server2 10.2.3.5
        volume glustervol
        content images,iso

8.8.2. File naming conventions

The directory layout and the file naming conventions are inherited from the dir backend.

8.8.3. Storage Features

The storage provides a file level interface, but no native snapshot/clone implementation.

Table 7. Storage features for backend glusterfs
Content types Image formats Shared Snapshots Clones

images vztmpl iso backup

raw qcow2 vmdk

yes

qcow2

qcow2

8.9. Local ZFS Pool Backend

Storage pool type: zfspool

This backend allows you to access local ZFS pools (or ZFS file systems inside such pools).

8.9.1. Configuration

The backend supports the common storage properties content, nodes, disable, and the following ZFS specific properties:

pool

Select the ZFS pool/filesystem. All allocations are done within that pool.

blocksize

Set ZFS blocksize parameter.

sparse

Use ZFS thin-provisioning. A sparse volume is a volume whose reservation is not equal to the volume size.

Configuration Example (/etc/pve/storage.cfg)
zfspool: vmdata
        pool tank/vmdata
        content rootdir,images
        sparse

8.9.2. File naming conventions

The backend uses the following naming scheme for VM images:

vm-<VMID>-<NAME>      // normal VM images
base-<VMID>-<NAME>    // template VM image (read-only)
subvol-<VMID>-<NAME>  // subvolumes (ZFS filesystem for containers)
<VMID>

This specifies the owner VM.

<NAME>

This can be an arbitrary name (ascii) without white space. The backend uses disk[N] as default, where [N] is replaced by an integer to make the name unique.

8.9.3. Storage Features

ZFS is probably the most advanced storage type regarding snapshot and cloning. The backend uses ZFS datasets for both VM images (format raw) and container data (format subvol). ZFS properties are inherited from the parent dataset, so you can simply set defaults on the parent dataset.

Table 8. Storage features for backend zfs
Content types Image formats Shared Snapshots Clones

images rootdir

raw subvol

no

yes

yes

8.9.4. Examples

It is recommended to create an extra ZFS file system to store your VM images:

# zfs create tank/vmdata

To enable compression on that newly allocated file system:

# zfs set compression=on tank/vmdata

You can get a list of available ZFS filesystems with:

# pvesm zfsscan

8.10. LVM Backend

Storage pool type: lvm

LVM is a light software layer on top of hard disks and partitions. It can be used to split available disk space into smaller logical volumes. LVM is widely used on Linux and makes managing hard drives easier.

Another use case is to put LVM on top of a big iSCSI LUN. That way you can easily manage space on that iSCSI LUN, which would not be possible otherwise, because the iSCSI specification does not define a management interface for space allocation.

8.10.1. Configuration

The LVM backend supports the common storage properties content, nodes, disable, and the following LVM specific properties:

vgname

LVM volume group name. This must point to an existing volume group.

base

Base volume. This volume is automatically activated before accessing the storage. This is mostly useful when the LVM volume group resides on a remote iSCSI server.

saferemove

Zero-out data when removing LVs. When removing a volume, this makes sure that all data gets erased.

saferemove_throughput

Wipe throughput (cstream -t parameter value).

Configuration Example (/etc/pve/storage.cfg)
lvm: myspace
        vgname myspace
        content rootdir,images

8.10.2. File naming conventions

The backend use basically the same naming conventions as the ZFS pool backend.

vm-<VMID>-<NAME>      // normal VM images

8.10.3. Storage Features

LVM is a typical block storage, but this backend does not support snapshot and clones. Unfortunately, normal LVM snapshots are quite inefficient, because they interfere all writes on the whole volume group during snapshot time.

One big advantage is that you can use it on top of a shared storage, for example an iSCSI LUN. The backend itself implement proper cluster wide locking.

Tip The newer LVM-thin backend allows snapshot and clones, but does not support shared storage.
Table 9. Storage features for backend lvm
Content types Image formats Shared Snapshots Clones

images rootdir

raw

possible

no

no

8.10.4. Examples

List available volume groups:

# pvesm lvmscan

8.11. LVM thin Backend

Storage pool type: lvmthin

LVM normally allocates blocks when you create a volume. LVM thin pools instead allocates blocks when they are written. This behaviour is called thin-provisioning, because volumes can be much larger than physically available space.

You can use the normal LVM command line tools to manage and create LVM thin pools (see man lvmthin for details). Assuming you already have a LVM volume group called pve, the following commands create a new LVM thin pool (size 100G) called data:

lvcreate -L 100G -n data pve
lvconvert --type thin-pool pve/data

8.11.1. Configuration

The LVM thin backend supports the common storage properties content, nodes, disable, and the following LVM specific properties:

vgname

LVM volume group name. This must point to an existing volume group.

thinpool

The name of the LVM thin pool.

Configuration Example (/etc/pve/storage.cfg)
lvmthin: local-lvm
        thinpool data
        vgname pve
        content rootdir,images

8.11.2. File naming conventions

The backend use basically the same naming conventions as the ZFS pool backend.

vm-<VMID>-<NAME>      // normal VM images

8.11.3. Storage Features

LVM thin is a block storage, but fully supports snapshots and clones efficiently. New volumes are automatically initialized with zero.

It must be mentioned that LVM thin pools cannot be shared across multiple nodes, so you can only use them as local storage.

Table 10. Storage features for backend lvmthin
Content types Image formats Shared Snapshots Clones

images rootdir

raw

no

yes

yes

8.11.4. Examples

List available LVM thin pools on volume group pve:

# pvesm lvmthinscan pve

8.12. Open-iSCSI initiator

Storage pool type: iscsi

iSCSI is a widely employed technology used to connect to storage servers. Almost all storage vendors support iSCSI. There are also open source iSCSI target solutions available, e.g. OpenMediaVault, which is based on Debian.

To use this backend, you need to install the Open-iSCSI (open-iscsi) package. This is a standard Debian package, but it is not installed by default to save resources.

# apt-get install open-iscsi

Low-level iscsi management task can be done using the iscsiadm tool.

8.12.1. Configuration

The backend supports the common storage properties content, nodes, disable, and the following iSCSI specific properties:

portal

iSCSI portal (IP or DNS name with optional port).

target

iSCSI target.

Configuration Example (/etc/pve/storage.cfg)
iscsi: mynas
     portal 10.10.10.1
     target iqn.2006-01.openfiler.com:tsn.dcb5aaaddd
     content none
Tip If you want to use LVM on top of iSCSI, it make sense to set content none. That way it is not possible to create VMs using iSCSI LUNs directly.

8.12.2. File naming conventions

The iSCSI protocol does not define an interface to allocate or delete data. Instead, that needs to be done on the target side and is vendor specific. The target simply exports them as numbered LUNs. So Proxmox VE iSCSI volume names just encodes some information about the LUN as seen by the linux kernel.

8.12.3. Storage Features

iSCSI is a block level type storage, and provides no management interface. So it is usually best to export one big LUN, and setup LVM on top of that LUN. You can then use the LVM plugin to manage the storage on that iSCSI LUN.

Table 11. Storage features for backend iscsi
Content types Image formats Shared Snapshots Clones

images none

raw

yes

no

no

8.12.4. Examples

Scan a remote iSCSI portal, and returns a list of possible targets:

pvesm iscsiscan -portal <HOST[:PORT]>

8.13. User Mode iSCSI Backend

Storage pool type: iscsidirect

This backend provides basically the same functionality as the Open-iSCSI backed, but uses a user-level library (package libiscsi2) to implement it.

It should be noted that there are no kernel drivers involved, so this can be viewed as performance optimization. But this comes with the drawback that you cannot use LVM on top of such iSCSI LUN. So you need to manage all space allocations at the storage server side.

8.13.1. Configuration

The user mode iSCSI backend uses the same configuration options as the Open-iSCSI backed.

Configuration Example (/etc/pve/storage.cfg)
iscsidirect: faststore
     portal 10.10.10.1
     target iqn.2006-01.openfiler.com:tsn.dcb5aaaddd

8.13.2. Storage Features

Note This backend works with VMs only. Containers cannot use this driver.
Table 12. Storage features for backend iscsidirect
Content types Image formats Shared Snapshots Clones

images

raw

yes

no

no

8.14. Ceph RADOS Block Devices (RBD)

Storage pool type: rbd

Ceph is a distributed object store and file system designed to provide excellent performance, reliability and scalability. RADOS block devices implement a feature rich block level storage, and you get the following advantages:

  • thin provisioning

  • resizable volumes

  • distributed and redundant (striped over multiple OSDs)

  • full snapshot and clone capabilities

  • self healing

  • no single point of failure

  • scalable to the exabyte level

  • kernel and user space implementation available

Note For smaller deployments, it is also possible to run Ceph services directly on your Proxmox VE nodes. Recent hardware has plenty of CPU power and RAM, so running storage services and VMs on same node is possible.

8.14.1. Configuration

This backend supports the common storage properties nodes, disable, content, and the following rbd specific properties:

monhost

List of monitor daemon IPs. Optional, only needed if Ceph is not running on the PVE cluster.

pool

Ceph pool name.

username

RBD user Id. Optional, only needed if Ceph is not running on the PVE cluster.

krbd

Access rbd through krbd kernel module. This is required if you want to use the storage for containers.

Configuration Example for a external Ceph cluster (/etc/pve/storage.cfg)
rbd: ceph-external
        monhost 10.1.1.20 10.1.1.21 10.1.1.22
        pool ceph-external
        content images
        username admin
Tip You can use the rbd utility to do low-level management tasks.

8.14.2. Authentication

If you use cephx authentication, you need to copy the keyfile from your external Ceph cluster to a Proxmox VE host.

Create the directory /etc/pve/priv/ceph with

mkdir /etc/pve/priv/ceph

Then copy the keyring

scp <cephserver>:/etc/ceph/ceph.client.admin.keyring /etc/pve/priv/ceph/<STORAGE_ID>.keyring

The keyring must be named to match your <STORAGE_ID>. Copying the keyring generally requires root privileges.

If Ceph is installed locally on the PVE cluster, this is done automatically by pveceph or in the GUI.

8.14.3. Storage Features

The rbd backend is a block level storage, and implements full snapshot and clone functionality.

Table 13. Storage features for backend rbd
Content types Image formats Shared Snapshots Clones

images rootdir

raw

yes

yes

yes

8.15. Ceph Filesystem (CephFS)

Storage pool type: cephfs

CephFS implements a POSIX-compliant filesystem using a Ceph storage cluster to store its data. As CephFS builds on Ceph it shares most of its properties, this includes redundancy, scalability, self healing and high availability.

Tip Proxmox VE can manage ceph setups, which makes configuring a CephFS storage easier. As recent hardware has plenty of CPU power and RAM, running storage services and VMs on same node is possible without a big performance impact.

8.15.1. Configuration

This backend supports the common storage properties nodes, disable, content, and the following cephfs specific properties:

monhost

List of monitor daemon addresses. Optional, only needed if Ceph is not running on the PVE cluster.

path

The local mount point. Optional, defaults to /mnt/pve/<STORAGE_ID>/.

username

Ceph user id. Optional, only needed if Ceph is not running on the PVE cluster where it defaults to admin.

subdir

CephFS subdirectory to mount. Optional, defaults to /.

fuse

Access CephFS through FUSE, instead of the kernel client. Optional, defaults to 0.

Configuration Example for a external Ceph cluster (/etc/pve/storage.cfg)
cephfs: cephfs-external
        monhost 10.1.1.20 10.1.1.21 10.1.1.22
        path /mnt/pve/cephfs-external
        content backup
        username admin
Note Don’t forget to setup the client secret key file if cephx was not turned off.

8.15.2. Authentication

If you use the, by-default enabled, cephx authentication, you need to copy the secret from your external Ceph cluster to a Proxmox VE host.

Create the directory /etc/pve/priv/ceph with

mkdir /etc/pve/priv/ceph

Then copy the secret

scp <cephserver>:/etc/ceph/cephfs.secret /etc/pve/priv/ceph/<STORAGE_ID>.secret

The secret must be named to match your <STORAGE_ID>. Copying the secret generally requires root privileges. The file must only contain the secret key itself, opposed to the rbd backend which also contains a [client.userid] section.

If Ceph is installed locally on the PVE cluster, i.e., setup with pveceph, this is done automatically.

8.15.3. Storage Features

The cephfs backend is a POSIX-compliant filesystem on top of a Ceph cluster.

Table 14. Storage features for backend cephfs
Content types Image formats Shared Snapshots Clones

vztmpl iso backup

none

yes

yes[1]

no

[1] Snapshots, while no known bugs, cannot be guaranteed to be stable yet, as they lack testing.

9. Storage Replication

The pvesr command line tool manages the Proxmox VE storage replication framework. Storage replication brings redundancy for guests using local storage and reduces migration time.

It replicates guest volumes to another node so that all data is available without using shared storage. Replication uses snapshots to minimize traffic sent over the network. Therefore, new data is sent only incrementally after an initial full sync. In the case of a node failure, your guest data is still available on the replicated node.

The replication will be done automatically in configurable intervals. The minimum replication interval is one minute and the maximal interval is once a week. The format used to specify those intervals is a subset of systemd calendar events, see Schedule Format section:

Every guest can be replicated to multiple target nodes, but a guest cannot get replicated twice to the same target node.

Each replications bandwidth can be limited, to avoid overloading a storage or server.

Virtual guest with active replication cannot currently use online migration. Offline migration is supported in general. If you migrate to a node where the guests data is already replicated only the changes since the last synchronisation (so called delta) must be sent, this reduces the required time significantly. In this case the replication direction will also switch nodes automatically after the migration finished.

For example: VM100 is currently on nodeA and gets replicated to nodeB. You migrate it to nodeB, so now it gets automatically replicated back from nodeB to nodeA.

If you migrate to a node where the guest is not replicated, the whole disk data must send over. After the migration the replication job continues to replicate this guest to the configured nodes.

Important

High-Availability is allowed in combination with storage replication, but it has the following implications:

  • redistributing services after a more preferred node comes online will lead to errors.

  • recovery works, but there may be some data loss between the last synced time and the time a node failed.

9.1. Supported Storage Types

Table 15. Storage Types
Description PVE type Snapshots Stable

ZFS (local)

zfspool

yes

yes

9.2. Schedule Format

Proxmox VE has a very flexible replication scheduler. It is based on the systemd time calendar event format.
[see man 7 systemd.time for more information]
Calendar events may be used to refer to one or more points in time in a single expression.

Such a calendar event uses the following format:

[day(s)] [[start-time(s)][/repetition-time(s)]]

This allows you to configure a set of days on which the job should run. You can also set one or more start times, it tells the replication scheduler the moments in time when a job should start. With this information we could create a job which runs every workday at 10 PM: 'mon,tue,wed,thu,fri 22' which could be abbreviated to: 'mon..fri 22', most reasonable schedules can be written quite intuitive this way.

Note Hours are set in 24h format.

To allow easier and shorter configuration one or more repetition times can be set. They indicate that on the start-time(s) itself and the start-time(s) plus all multiples of the repetition value replications will be done. If you want to start replication at 8 AM and repeat it every 15 minutes until 9 AM you would use: '8:00/15'

Here you see also that if no hour separation (:) is used the value gets interpreted as minute. If such a separation is used the value on the left denotes the hour(s) and the value on the right denotes the minute(s). Further, you can use * to match all possible values.

To get additional ideas look at more Examples below.

9.2.1. Detailed Specification

days

Days are specified with an abbreviated English version: sun, mon, tue, wed, thu, fri and sat. You may use multiple days as a comma-separated list. A range of days can also be set by specifying the start and end day separated by “..”, for example mon..fri. Those formats can be also mixed. If omitted '*' is assumed.

time-format

A time format consists of hours and minutes interval lists. Hours and minutes are separated by ':'. Both, hour and minute, can be list and ranges of values, using the same format as days. First come hours then minutes, hours can be omitted if not needed, in this case '*' is assumed for the value of hours. The valid range for values is 0-23 for hours and 0-59 for minutes.

9.2.2. Examples:

Table 16. Schedule Examples
Schedule String Alternative Meaning

mon,tue,wed,thu,fri

mon..fri

Every working day at 0:00

sat,sun

sat..sun

Only on weekends at 0:00

mon,wed,fri

— 

Only on Monday, Wednesday and Friday at 0:00

12:05

12:05

Every day at 12:05 PM

*/5

0/5

Every five minutes

mon..wed 30/10

mon,tue,wed 30/10

Monday, Tuesday, Wednesday 30, 40 and 50 minutes after every full hour

mon..fri 8..17,22:0/15

— 

Every working day every 15 minutes between 8 AM and 6 PM and between 10 PM and 11 PM

fri 12..13:5/20

fri 12,13:5/20

Friday at 12:05, 12:25, 12:45, 13:05, 13:25 and 13:45

12,14,16,18,20,22:5

12/2:5

Every day starting at 12:05 until 22:05, every 2 hours

*

*/1

Every minute (minimum interval)

9.3. Error Handling

If a replication job encounters problems it will be placed in error state. In this state the configured replication intervals get suspended temporarily. Then we retry the failed replication in a 30 minute interval, once this succeeds the original schedule gets activated again.

9.3.1. Possible issues

This represents only the most common issues possible, depending on your setup there may be also another cause.

  • Network is not working.

  • No free space left on the replication target storage.

  • Storage with same storage ID available on target node

Note You can always use the replication log to get hints about a problems cause.

9.3.2. Migrating a guest in case of Error

In the case of a grave error a virtual guest may get stuck on a failed node. You then need to move it manually to a working node again.

9.3.3. Example

Lets assume that you have two guests (VM 100 and CT 200) running on node A and replicate to node B. Node A failed and can not get back online. Now you have to migrate the guest to Node B manually.

  • connect to node B over ssh or open its shell via the WebUI

  • check if that the cluster is quorate

    # pvecm status
  • If you have no quorum we strongly advise to fix this first and make the node operable again. Only if this is not possible at the moment you may use the following command to enforce quorum on the current node:

    # pvecm expected 1
Warning If expected votes are set avoid changes which affect the cluster (for example adding/removing nodes, storages, virtual guests) at all costs. Only use it to get vital guests up and running again or to resolve to quorum issue itself.
  • move both guest configuration files form the origin node A to node B:

    # mv /etc/pve/nodes/A/qemu-server/100.conf /etc/pve/nodes/B/qemu-server/100.conf
    # mv /etc/pve/nodes/A/lxc/200.conf /etc/pve/nodes/B/lxc/200.conf
  • Now you can start the guests again:

    # qm start 100
    # pct start 200

Remember to replace the VMIDs and node names with your respective values.

9.4. Managing Jobs

gui-qemu-add-replication-job.png

You can use the web GUI to create, modify and remove replication jobs easily. Additionally the command line interface (CLI) tool pvesr can be used to do this.

You can find the replication panel on all levels (datacenter, node, virtual guest) in the web GUI. They differ in what jobs get shown: all, only node specific or only guest specific jobs.

Once adding a new job you need to specify the virtual guest (if not already selected) and the target node. The replication schedule can be set if the default of all 15 minutes is not desired. You may also impose rate limiting on a replication job, this can help to keep the storage load acceptable.

A replication job is identified by an cluster-wide unique ID. This ID is composed of the VMID in addition to an job number. This ID must only be specified manually if the CLI tool is used.

9.5. Command Line Interface Examples

Create a replication job which will run every 5 minutes with limited bandwidth of 10 mbps (megabytes per second) for the guest with guest ID 100.

# pvesr create-local-job 100-0 pve1 --schedule "*/5" --rate 10

Disable an active job with ID 100-0

# pvesr disable 100-0

Enable a deactivated job with ID 100-0

# pvesr enable 100-0

Change the schedule interval of the job with ID 100-0 to once a hour

# pvesr update 100-0 --schedule '*/00'

10. Qemu/KVM Virtual Machines

Qemu (short form for Quick Emulator) is an open source hypervisor that emulates a physical computer. From the perspective of the host system where Qemu is running, Qemu is a user program which has access to a number of local resources like partitions, files, network cards which are then passed to an emulated computer which sees them as if they were real devices.

A guest operating system running in the emulated computer accesses these devices, and runs as it were running on real hardware. For instance you can pass an iso image as a parameter to Qemu, and the OS running in the emulated computer will see a real CDROM inserted in a CD drive.

Qemu can emulate a great variety of hardware from ARM to Sparc, but Proxmox VE is only concerned with 32 and 64 bits PC clone emulation, since it represents the overwhelming majority of server hardware. The emulation of PC clones is also one of the fastest due to the availability of processor extensions which greatly speed up Qemu when the emulated architecture is the same as the host architecture.

Note You may sometimes encounter the term KVM (Kernel-based Virtual Machine). It means that Qemu is running with the support of the virtualization processor extensions, via the Linux kvm module. In the context of Proxmox VE Qemu and KVM can be used interchangeably as Qemu in Proxmox VE will always try to load the kvm module.

Qemu inside Proxmox VE runs as a root process, since this is required to access block and PCI devices.

10.1. Emulated devices and paravirtualized devices

The PC hardware emulated by Qemu includes a mainboard, network controllers, scsi, ide and sata controllers, serial ports (the complete list can be seen in the kvm(1) man page) all of them emulated in software. All these devices are the exact software equivalent of existing hardware devices, and if the OS running in the guest has the proper drivers it will use the devices as if it were running on real hardware. This allows Qemu to runs unmodified operating systems.

This however has a performance cost, as running in software what was meant to run in hardware involves a lot of extra work for the host CPU. To mitigate this, Qemu can present to the guest operating system paravirtualized devices, where the guest OS recognizes it is running inside Qemu and cooperates with the hypervisor.

Qemu relies on the virtio virtualization standard, and is thus able to present paravirtualized virtio devices, which includes a paravirtualized generic disk controller, a paravirtualized network card, a paravirtualized serial port, a paravirtualized SCSI controller, etc …

It is highly recommended to use the virtio devices whenever you can, as they provide a big performance improvement. Using the virtio generic disk controller versus an emulated IDE controller will double the sequential write throughput, as measured with bonnie++(8). Using the virtio network interface can deliver up to three times the throughput of an emulated Intel E1000 network card, as measured with iperf(1).
[See this benchmark on the KVM wiki http://www.linux-kvm.org/page/Using_VirtIO_NIC]

10.2. Virtual Machines Settings

Generally speaking Proxmox VE tries to choose sane defaults for virtual machines (VM). Make sure you understand the meaning of the settings you change, as it could incur a performance slowdown, or putting your data at risk.

10.2.1. General Settings

gui-create-vm-general.png

General settings of a VM include

  • the Node : the physical server on which the VM will run

  • the VM ID: a unique number in this Proxmox VE installation used to identify your VM

  • Name: a free form text string you can use to describe the VM

  • Resource Pool: a logical group of VMs

10.2.2. OS Settings

gui-create-vm-os.png

When creating a VM, setting the proper Operating System(OS) allows Proxmox VE to optimize some low level parameters. For instance Windows OS expect the BIOS clock to use the local time, while Unix based OS expect the BIOS clock to have the UTC time.

10.2.3. Hard Disk

Qemu can emulate a number of storage controllers:

  • the IDE controller, has a design which goes back to the 1984 PC/AT disk controller. Even if this controller has been superseded by recent designs, each and every OS you can think of has support for it, making it a great choice if you want to run an OS released before 2003. You can connect up to 4 devices on this controller.

  • the SATA (Serial ATA) controller, dating from 2003, has a more modern design, allowing higher throughput and a greater number of devices to be connected. You can connect up to 6 devices on this controller.

  • the SCSI controller, designed in 1985, is commonly found on server grade hardware, and can connect up to 14 storage devices. Proxmox VE emulates by default a LSI 53C895A controller.

    A SCSI controller of type VirtIO SCSI is the recommended setting if you aim for performance and is automatically selected for newly created Linux VMs since Proxmox VE 4.3. Linux distributions have support for this controller since 2012, and FreeBSD since 2014. For Windows OSes, you need to provide an extra iso containing the drivers during the installation. If you aim at maximum performance, you can select a SCSI controller of type VirtIO SCSI single which will allow you to select the IO Thread option. When selecting VirtIO SCSI single Qemu will create a new controller for each disk, instead of adding all disks to the same controller.

  • The VirtIO Block controller, often just called VirtIO or virtio-blk, is an older type of paravirtualized controller. It has been superseded by the VirtIO SCSI Controller, in terms of features.

gui-create-vm-hard-disk.png

On each controller you attach a number of emulated hard disks, which are backed by a file or a block device residing in the configured storage. The choice of a storage type will determine the format of the hard disk image. Storages which present block devices (LVM, ZFS, Ceph) will require the raw disk image format, whereas files based storages (Ext4, NFS, CIFS, GlusterFS) will let you to choose either the raw disk image format or the QEMU image format.

  • the QEMU image format is a copy on write format which allows snapshots, and thin provisioning of the disk image.

  • the raw disk image is a bit-to-bit image of a hard disk, similar to what you would get when executing the dd command on a block device in Linux. This format does not support thin provisioning or snapshots by itself, requiring cooperation from the storage layer for these tasks. It may, however, be up to 10% faster than the QEMU image format.
    [See this benchmark for details http://events.linuxfoundation.org/sites/events/files/slides/CloudOpen2013_Khoa_Huynh_v3.pdf]

  • the VMware image format only makes sense if you intend to import/export the disk image to other hypervisors.

Setting the Cache mode of the hard drive will impact how the host system will notify the guest systems of block write completions. The No cache default means that the guest system will be notified that a write is complete when each block reaches the physical storage write queue, ignoring the host page cache. This provides a good balance between safety and speed.

If you want the Proxmox VE backup manager to skip a disk when doing a backup of a VM, you can set the No backup option on that disk.

If you want the Proxmox VE storage replication mechanism to skip a disk when starting a replication job, you can set the Skip replication option on that disk. As of Proxmox VE 5.0, replication requires the disk images to be on a storage of type zfspool, so adding a disk image to other storages when the VM has replication configured requires to skip replication for this disk image.

If your storage supports thin provisioning (see the storage chapter in the Proxmox VE guide), and your VM has a SCSI controller you can activate the Discard option on the hard disks connected to that controller. With Discard enabled, when the filesystem of a VM marks blocks as unused after removing files, the emulated SCSI controller will relay this information to the storage, which will then shrink the disk image accordingly.

IO Thread

The option IO Thread can only be used when using a disk with the VirtIO controller, or with the SCSI controller, when the emulated controller type is VirtIO SCSI single. With this enabled, Qemu creates one I/O thread per storage controller, instead of a single thread for all I/O, so it increases performance when multiple disks are used and each disk has its own storage controller. Note that backups do not currently work with IO Thread enabled.

10.2.4. CPU

gui-create-vm-cpu.png

A CPU socket is a physical slot on a PC motherboard where you can plug a CPU. This CPU can then contain one or many cores, which are independent processing units. Whether you have a single CPU socket with 4 cores, or two CPU sockets with two cores is mostly irrelevant from a performance point of view. However some software licenses depend on the number of sockets a machine has, in that case it makes sense to set the number of sockets to what the license allows you.

Increasing the number of virtual cpus (cores and sockets) will usually provide a performance improvement though that is heavily dependent on the use of the VM. Multithreaded applications will of course benefit from a large number of virtual cpus, as for each virtual cpu you add, Qemu will create a new thread of execution on the host system. If you’re not sure about the workload of your VM, it is usually a safe bet to set the number of Total cores to 2.

Note It is perfectly safe if the overall number of cores of all your VMs is greater than the number of cores on the server (e.g., 4 VMs with each 4 cores on a machine with only 8 cores). In that case the host system will balance the Qemu execution threads between your server cores, just like if you were running a standard multithreaded application. However, Proxmox VE will prevent you from assigning more virtual CPU cores than physically available, as this will only bring the performance down due to the cost of context switches.
Resource Limits

In addition to the number of virtual cores, you can configure how much resources a VM can get in relation to the host CPU time and also in relation to other VMs. With the cpulimit (“Host CPU Time”) option you can limit how much CPU time the whole VM can use on the host. It is a floating point value representing CPU time in percent, so 1.0 is equal to 100%, 2.5 to 250% and so on. If a single process would fully use one single core it would have 100% CPU Time usage. If a VM with four cores utilizes all its cores fully it would theoretically use 400%. In reality the usage may be even a bit higher as Qemu can have additional threads for VM peripherals besides the vCPU core ones. This setting can be useful if a VM should have multiple vCPUs, as it runs a few processes in parallel, but the VM as a whole should not be able to run all vCPUs at 100% at the same time. Using a specific example: lets say we have a VM which would profit from having 8 vCPUs, but at no time all of those 8 cores should run at full load - as this would make the server so overloaded that other VMs and CTs would get to less CPU. So, we set the cpulimit limit to 4.0 (=400%). If all cores do the same heavy work they would all get 50% of a real host cores CPU time. But, if only 4 would do work they could still get almost 100% of a real core each.

Note VMs can, depending on their configuration, use additional threads e.g., for networking or IO operations but also live migration. Thus a VM can show up to use more CPU time than just its virtual CPUs could use. To ensure that a VM never uses more CPU time than virtual CPUs assigned set the cpulimit setting to the same value as the total core count.

The second CPU resource limiting setting, cpuunits (nowadays often called CPU shares or CPU weight), controls how much CPU time a VM gets in regards to other VMs running. It is a relative weight which defaults to 1024, if you increase this for a VM it will be prioritized by the scheduler in comparison to other VMs with lower weight. E.g., if VM 100 has set the default 1024 and VM 200 was changed to 2048, the latter VM 200 would receive twice the CPU bandwidth than the first VM 100.

For more information see man systemd.resource-control, here CPUQuota corresponds to cpulimit and CPUShares corresponds to our cpuunits setting, visit its Notes section for references and implementation details.

CPU Type

Qemu can emulate a number different of CPU types from 486 to the latest Xeon processors. Each new processor generation adds new features, like hardware assisted 3d rendering, random number generation, memory protection, etc … Usually you should select for your VM a processor type which closely matches the CPU of the host system, as it means that the host CPU features (also called CPU flags ) will be available in your VMs. If you want an exact match, you can set the CPU type to host in which case the VM will have exactly the same CPU flags as your host system.

This has a downside though. If you want to do a live migration of VMs between different hosts, your VM might end up on a new system with a different CPU type. If the CPU flags passed to the guest are missing, the qemu process will stop. To remedy this Qemu has also its own CPU type kvm64, that Proxmox VE uses by defaults. kvm64 is a Pentium 4 look a like CPU type, which has a reduced CPU flags set, but is guaranteed to work everywhere.

In short, if you care about live migration and moving VMs between nodes, leave the kvm64 default. If you don’t care about live migration or have a homogeneous cluster where all nodes have the same CPU, set the CPU type to host, as in theory this will give your guests maximum performance.

There are two CPU flags related to the Meltdown and Spectre vulnerabilities
[Meltdown Attack https://meltdownattack.com/]
which need to be set manually unless the selected CPU type of your VM already enables them by default.

The first, called pcid, helps to reduce the performance impact of the Meltdown mitigation called Kernel Page-Table Isolation (KPTI), which effectively hides the Kernel memory from the user space. Without PCID, KPTI is quite an expensive mechanism
[PCID is now a critical performance/security feature on x86 https://groups.google.com/forum/m/#!topic/mechanical-sympathy/L9mHTbeQLNU]
.

The second CPU flag is called spec-ctrl, which allows an operating system to selectively disable or restrict speculative execution in order to limit the ability of attackers to exploit the Spectre vulnerability.

There are two requirements that need to be fulfilled in order to use these two CPU flags:

  • The host CPU(s) must support the feature and propagate it to the guest’s virtual CPU(s)

  • The guest operating system must be updated to a version which mitigates the attacks and is able to utilize the CPU feature

In order to use spec-ctrl, your CPU or system vendor also needs to provide a so-called “microcode update”
[You can use ‘intel-microcode’ / ‘amd-microcode’ from Debian non-free if your vendor does not provide such an update. Note that not all affected CPUs can be updated to support spec-ctrl.]
for your CPU.

To check if the Proxmox VE host supports PCID, execute the following command as root:

# grep ' pcid ' /proc/cpuinfo

If this does not return empty your host’s CPU has support for pcid.

To check if the Proxmox VE host supports spec-ctrl, execute the following command as root:

# grep ' spec_ctrl ' /proc/cpuinfo

If this does not return empty your host’s CPU has support for spec-ctrl.

If you use ‘host’ or another CPU type which enables the desired flags by default, and you updated your guest OS to make use of the associated CPU features, you’re already set.

Otherwise you need to set the desired CPU flag of the virtual CPU, either by editing the CPU options in the WebUI, or by setting the flags property of the cpu option in the VM configuration file.

NUMA

You can also optionally emulate a NUMA
[https://en.wikipedia.org/wiki/Non-uniform_memory_access]
architecture in your VMs. The basics of the NUMA architecture mean that instead of having a global memory pool available to all your cores, the memory is spread into local banks close to each socket. This can bring speed improvements as the memory bus is not a bottleneck anymore. If your system has a NUMA architecture
[if the command numactl --hardware | grep available returns more than one node, then your host system has a NUMA architecture]
we recommend to activate the option, as this will allow proper distribution of the VM resources on the host system. This option is also required to hot-plug cores or RAM in a VM.

If the NUMA option is used, it is recommended to set the number of sockets to the number of sockets of the host system.

vCPU hot-plug

Modern operating systems introduced the capability to hot-plug and, to a certain extent, hot-unplug CPUs in a running systems. Virtualisation allows us to avoid a lot of the (physical) problems real hardware can cause in such scenarios. Still, this is a rather new and complicated feature, so its use should be restricted to cases where its absolutely needed. Most of the functionality can be replicated with other, well tested and less complicated, features, see Resource Limits.

In Proxmox VE the maximal number of plugged CPUs is always cores * sockets. To start a VM with less than this total core count of CPUs you may use the vpus setting, it denotes how many vCPUs should be plugged in at VM start.

Currently only this feature is only supported on Linux, a kernel newer than 3.10 is needed, a kernel newer than 4.7 is recommended.

You can use a udev rule as follow to automatically set new CPUs as online in the guest:

SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}="1"

Save this under /etc/udev/rules.d/ as a file ending in .rules.

Note: CPU hot-remove is machine dependent and requires guest cooperation. The deletion command does not guarantee CPU removal to actually happen, typically it’s a request forwarded to guest using target dependent mechanism, e.g., ACPI on x86/amd64.

10.2.5. Memory

For each VM you have the option to set a fixed size memory or asking Proxmox VE to dynamically allocate memory based on the current RAM usage of the host.

gui-create-vm-memory.png
Fixed Memory Allocation

When setting memory and minimum memory to the same amount Proxmox VE will simply allocate what you specify to your VM.

Even when using a fixed memory size, the ballooning device gets added to the VM, because it delivers useful information such as how much memory the guest really uses. In general, you should leave ballooning enabled, but if you want to disable it (e.g. for debugging purposes), simply uncheck Ballooning Device or set

balloon: 0

in the configuration.

Automatic Memory Allocation

When setting the minimum memory lower than memory, Proxmox VE will make sure that the minimum amount you specified is always available to the VM, and if RAM usage on the host is below 80%, will dynamically add memory to the guest up to the maximum memory specified.

When the host is becoming short on RAM, the VM will then release some memory back to the host, swapping running processes if needed and starting the oom killer in last resort. The passing around of memory between host and guest is done via a special balloon kernel driver running inside the guest, which will grab or release memory pages from the host.
[A good explanation of the inner workings of the balloon driver can be found here https://rwmj.wordpress.com/2010/07/17/virtio-balloon/]

When multiple VMs use the autoallocate facility, it is possible to set a Shares coefficient which indicates the relative amount of the free host memory that each VM should take. Suppose for instance you have four VMs, three of them running a HTTP server and the last one is a database server. To cache more database blocks in the database server RAM, you would like to prioritize the database VM when spare RAM is available. For this you assign a Shares property of 3000 to the database VM, leaving the other VMs to the Shares default setting of 1000. The host server has 32GB of RAM, and is currently using 16GB, leaving 32 * 80/100 - 16 = 9GB RAM to be allocated to the VMs. The database VM will get 9 * 3000 / (3000 + 1000 + 1000 + 1000) = 4.5 GB extra RAM and each HTTP server will get 1/5 GB.

All Linux distributions released after 2010 have the balloon kernel driver included. For Windows OSes, the balloon driver needs to be added manually and can incur a slowdown of the guest, so we don’t recommend using it on critical systems.

When allocating RAM to your VMs, a good rule of thumb is always to leave 1GB of RAM available to the host.

10.2.6. Network Device

gui-create-vm-network.png

Each VM can have many Network interface controllers (NIC), of four different types:

  • Intel E1000 is the default, and emulates an Intel Gigabit network card.

  • the VirtIO paravirtualized NIC should be used if you aim for maximum performance. Like all VirtIO devices, the guest OS should have the proper driver installed.

  • the Realtek 8139 emulates an older 100 MB/s network card, and should only be used when emulating older operating systems ( released before 2002 )

  • the vmxnet3 is another paravirtualized device, which should only be used when importing a VM from another hypervisor.

Proxmox VE will generate for each NIC a random MAC address, so that your VM is addressable on Ethernet networks.

The NIC you added to the VM can follow one of two different models:

  • in the default Bridged mode each virtual NIC is backed on the host by a tap device, ( a software loopback device simulating an Ethernet NIC ). This tap device is added to a bridge, by default vmbr0 in Proxmox VE. In this mode, VMs have direct access to the Ethernet LAN on which the host is located.

  • in the alternative NAT mode, each virtual NIC will only communicate with the Qemu user networking stack, where a built-in router and DHCP server can provide network access. This built-in DHCP will serve addresses in the private 10.0.2.0/24 range. The NAT mode is much slower than the bridged mode, and should only be used for testing. This mode is only available via CLI or the API, but not via the WebUI.

You can also skip adding a network device when creating a VM by selecting No network device.

Multiqueue

If you are using the VirtIO driver, you can optionally activate the Multiqueue option. This option allows the guest OS to process networking packets using multiple virtual CPUs, providing an increase in the total number of packets transferred.

When using the VirtIO driver with Proxmox VE, each NIC network queue is passed to the host kernel, where the queue will be processed by a kernel thread spawn by the vhost driver. With this option activated, it is possible to pass multiple network queues to the host kernel for each NIC.

When using Multiqueue, it is recommended to set it to a value equal to the number of Total Cores of your guest. You also need to set in the VM the number of multi-purpose channels on each VirtIO NIC with the ethtool command:

ethtool -L ens1 combined X

where X is the number of the number of vcpus of the VM.

You should note that setting the Multiqueue parameter to a value greater than one will increase the CPU load on the host and guest systems as the traffic increases. We recommend to set this option only when the VM has to process a great number of incoming connections, such as when the VM is running as a router, reverse proxy or a busy HTTP server doing long polling.

10.2.7. USB Passthrough

There are two different types of USB passthrough devices:

  • Host USB passthrough

  • SPICE USB passthrough

Host USB passthrough works by giving a VM a USB device of the host. This can either be done via the vendor- and product-id, or via the host bus and port.

The vendor/product-id looks like this: 0123:abcd, where 0123 is the id of the vendor, and abcd is the id of the product, meaning two pieces of the same usb device have the same id.

The bus/port looks like this: 1-2.3.4, where 1 is the bus and 2.3.4 is the port path. This represents the physical ports of your host (depending of the internal order of the usb controllers).

If a device is present in a VM configuration when the VM starts up, but the device is not present in the host, the VM can boot without problems. As soon as the device/port is available in the host, it gets passed through.

Warning Using this kind of USB passthrough means that you cannot move a VM online to another host, since the hardware is only available on the host the VM is currently residing.

The second type of passthrough is SPICE USB passthrough. This is useful if you use a SPICE client which supports it. If you add a SPICE USB port to your VM, you can passthrough a USB device from where your SPICE client is, directly to the VM (for example an input device or hardware dongle).

10.2.8. BIOS and UEFI

In order to properly emulate a computer, QEMU needs to use a firmware. By default QEMU uses SeaBIOS for this, which is an open-source, x86 BIOS implementation. SeaBIOS is a good choice for most standard setups.

There are, however, some scenarios in which a BIOS is not a good firmware to boot from, e.g. if you want to do VGA passthrough.
[Alex Williamson has a very good blog entry about this. http://vfio.blogspot.co.at/2014/08/primary-graphics-assignment-without-vga.html]
In such cases, you should rather use OVMF, which is an open-source UEFI implementation.
[See the OVMF Project http://www.tianocore.org/ovmf/]

If you want to use OVMF, there are several things to consider:

In order to save things like the boot order, there needs to be an EFI Disk. This disk will be included in backups and snapshots, and there can only be one.

You can create such a disk with the following command:

qm set <vmid> -efidisk0 <storage>:1,format=<format>

Where <storage> is the storage where you want to have the disk, and <format> is a format which the storage supports. Alternatively, you can create such a disk through the web interface with AddEFI Disk in the hardware section of a VM.

When using OVMF with a virtual display (without VGA passthrough), you need to set the client resolution in the OVMF menu(which you can reach with a press of the ESC button during boot), or you have to choose SPICE as the display type.

10.2.9. Automatic Start and Shutdown of Virtual Machines

After creating your VMs, you probably want them to start automatically when the host system boots. For this you need to select the option Start at boot from the Options Tab of your VM in the web interface, or set it with the following command:

qm set <vmid> -onboot 1
gui-qemu-edit-start-order.png
Start and Shutdown Order

In some case you want to be able to fine tune the boot order of your VMs, for instance if one of your VM is providing firewalling or DHCP to other guest systems. For this you can use the following parameters:

  • Start/Shutdown order: Defines the start order priority. E.g. set it to 1 if you want the VM to be the first to be started. (We use the reverse startup order for shutdown, so a machine with a start order of 1 would be the last to be shut down). If multiple VMs have the same order defined on a host, they will additionally be ordered by VMID in ascending order.

  • Startup delay: Defines the interval between this VM start and subsequent VMs starts . E.g. set it to 240 if you want to wait 240 seconds before starting other VMs.

  • Shutdown timeout: Defines the duration in seconds Proxmox VE should wait for the VM to be offline after issuing a shutdown command. By default this value is set to 180, which means that Proxmox VE will issue a shutdown request and wait 180 seconds for the machine to be offline. If the machine is still online after the timeout it will be stopped forcefully.

Note VMs managed by the HA stack do not follow the start on boot and boot order options currently. Those VMs will be skipped by the startup and shutdown algorithm as the HA manager itself ensures that VMs get started and stopped.

Please note that machines without a Start/Shutdown order parameter will always start after those where the parameter is set. Further, this parameter can only be enforced between virtual machines running on the same host, not cluster-wide.

10.3. Migration

gui-qemu-migrate.png

If you have a cluster, you can migrate your VM to another host with

qm migrate <vmid> <target>

There are generally two mechanisms for this

  • Online Migration (aka Live Migration)

  • Offline Migration

10.3.1. Online Migration

When your VM is running and it has no local resources defined (such as disks on local storage, passed through devices, etc.) you can initiate a live migration with the -online flag.

How it works

This starts a Qemu Process on the target host with the incoming flag, which means that the process starts and waits for the memory data and device states from the source Virtual Machine (since all other resources, e.g. disks, are shared, the memory content and device state are the only things left to transmit).

Once this connection is established, the source begins to send the memory content asynchronously to the target. If the memory on the source changes, those sections are marked dirty and there will be another pass of sending data. This happens until the amount of data to send is so small that it can pause the VM on the source, send the remaining data to the target and start the VM on the target in under a second.

Requirements

For Live Migration to work, there are some things required:

  • The VM has no local resources (e.g. passed through devices, local disks, etc.)

  • The hosts are in the same Proxmox VE cluster.

  • The hosts have a working (and reliable) network connection.

  • The target host must have the same or higher versions of the Proxmox VE packages. (It might work the other way, but this is never guaranteed)

10.3.2. Offline Migration

If you have local resources, you can still offline migrate your VMs, as long as all disk are on storages, which are defined on both hosts. Then the migration will copy the disk over the network to the target host.

10.4. Copies and Clones

gui-qemu-full-clone.png

VM installation is usually done using an installation media (CD-ROM) from the operation system vendor. Depending on the OS, this can be a time consuming task one might want to avoid.

An easy way to deploy many VMs of the same type is to copy an existing VM. We use the term clone for such copies, and distinguish between linked and full clones.

Full Clone

The result of such copy is an independent VM. The new VM does not share any storage resources with the original.

It is possible to select a Target Storage, so one can use this to migrate a VM to a totally different storage. You can also change the disk image Format if the storage driver supports several formats.

Note A full clone need to read and copy all VM image data. This is usually much slower than creating a linked clone.

Some storage types allows to copy a specific Snapshot, which defaults to the current VM data. This also means that the final copy never includes any additional snapshots from the original VM.

Linked Clone

Modern storage drivers supports a way to generate fast linked clones. Such a clone is a writable copy whose initial contents are the same as the original data. Creating a linked clone is nearly instantaneous, and initially consumes no additional space.

They are called linked because the new image still refers to the original. Unmodified data blocks are read from the original image, but modification are written (and afterwards read) from a new location. This technique is called Copy-on-write.

This requires that the original volume is read-only. With Proxmox VE one can convert any VM into a read-only Template). Such templates can later be used to create linked clones efficiently.

Note You cannot delete the original template while linked clones exists.

It is not possible to change the Target storage for linked clones, because this is a storage internal feature.

The Target node option allows you to create the new VM on a different node. The only restriction is that the VM is on shared storage, and that storage is also available on the target node.

To avoid resource conflicts, all network interface MAC addresses gets randomized, and we generate a new UUID for the VM BIOS (smbios1) setting.

10.5. Virtual Machine Templates

One can convert a VM into a Template. Such templates are read-only, and you can use them to create linked clones.

Note It is not possible to start templates, because this would modify the disk images. If you want to change the template, create a linked clone and modify that.

10.6. Importing Virtual Machines and disk images

A VM export from a foreign hypervisor takes usually the form of one or more disk images, with a configuration file describing the settings of the VM (RAM, number of cores).
The disk images can be in the vmdk format, if the disks come from VMware or VirtualBox, or qcow2 if the disks come from a KVM hypervisor. The most popular configuration format for VM exports is the OVF standard, but in practice interoperation is limited because many settings are not implemented in the standard itself, and hypervisors export the supplementary information in non-standard extensions.

Besides the problem of format, importing disk images from other hypervisors may fail if the emulated hardware changes too much from one hypervisor to another. Windows VMs are particularly concerned by this, as the OS is very picky about any changes of hardware. This problem may be solved by installing the MergeIDE.zip utility available from the Internet before exporting and choosing a hard disk type of IDE before booting the imported Windows VM.

Finally there is the question of paravirtualized drivers, which improve the speed of the emulated system and are specific to the hypervisor. GNU/Linux and other free Unix OSes have all the necessary drivers installed by default and you can switch to the paravirtualized drivers right after importing the VM. For Windows VMs, you need to install the Windows paravirtualized drivers by yourself.

GNU/Linux and other free Unix can usually be imported without hassle. Note that we cannot guarantee a successful import/export of Windows VMs in all cases due to the problems above.

10.6.1. Step-by-step example of a Windows OVF import

Microsoft provides Virtual Machines downloads to get started with Windows development.We are going to use one of these to demonstrate the OVF import feature.

Download the Virtual Machine zip

After getting informed about the user agreement, choose the Windows 10 Enterprise (Evaluation - Build) for the VMware platform, and download the zip.

Extract the disk image from the zip

Using the unzip utility or any archiver of your choice, unpack the zip, and copy via ssh/scp the ovf and vmdk files to your Proxmox VE host.

Import the Virtual Machine

This will create a new virtual machine, using cores, memory and VM name as read from the OVF manifest, and import the disks to the local-lvm storage. You have to configure the network manually.

qm importovf 999 WinDev1709Eval.ovf local-lvm

The VM is ready to be started.

10.6.2. Adding an external disk image to a Virtual Machine

You can also add an existing disk image to a VM, either coming from a foreign hypervisor, or one that you created yourself.

Suppose you created a Debian/Ubuntu disk image with the vmdebootstrap tool:

vmdebootstrap --verbose \
 --size 10GiB --serial-console \
 --grub --no-extlinux \
 --package openssh-server \
 --package avahi-daemon \
 --package qemu-guest-agent \
 --hostname vm600 --enable-dhcp \
 --customize=./copy_pub_ssh.sh \
 --sparse --image vm600.raw

You can now create a new target VM for this image.

qm create 600 --net0 virtio,bridge=vmbr0 --name vm600 --serial0 socket \
  --bootdisk scsi0 --scsihw virtio-scsi-pci --ostype l26

Add the disk image as unused0 to the VM, using the storage pvedir:

qm importdisk 600 vm600.raw pvedir

Finally attach the unused disk to the SCSI controller of the VM:

qm set 600 --scsi0 pvedir:600/vm-600-disk-1.raw

The VM is ready to be started.

10.7. Cloud-Init Support

Cloud-Init is the defacto multi-distribution package that handles early initialization of a virtual machine instance. Using Cloud-Init, configuration of network devices and ssh keys on the hypervisor side is possible. When the VM starts for the first time, the Cloud-Init software inside the VM will apply those settings.

Many Linux distributions provide ready-to-use Cloud-Init images, mostly designed for OpenStack. These images will also work with Proxmox VE. While it may seem convenient to get such ready-to-use images, we usually recommended to prepare the images by yourself. The advantage is that you will know exactly what you have installed, and this helps you later to easily customize the image for your needs.

Once you have created such a Cloud-Init image we recommend to convert it into a VM template. From a VM template you can quickly create linked clones, so this is a fast method to roll out new VM instances. You just need to configure the network (and maybe the ssh keys) before you start the new VM.

We recommend using SSH key-based authentication to login to the VMs provisioned by Cloud-Init. It is also possible to set a password, but this is not as safe as using SSH key-based authentication because Proxmox VE needs to store an encrypted version of that password inside the Cloud-Init data.

Proxmox VE generates an ISO image to pass the Cloud-Init data to the VM. For that purpose all Cloud-Init VMs need to have an assigned CDROM drive. Also many Cloud-Init images assume to have a serial console, so it is recommended to add a serial console and use it as display for those VMs.

10.7.1. Preparing Cloud-Init Templates

The first step is to prepare your VM. Basically you can use any VM. Simply install the Cloud-Init packages inside the VM that you want to prepare. On Debian/Ubuntu based systems this is as simple as:

apt-get install cloud-init

Already many distributions provide ready-to-use Cloud-Init images (provided as .qcow2 files), so alternatively you can simply download and import such images. For the following example, we will use the cloud image provided by Ubuntu at https://cloud-images.ubuntu.com.

# download the image
wget https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img

# create a new VM
qm create 9000 --memory 2048 --net0 virtio,bridge=vmbr0

# import the downloaded disk to local-lvm storage
qm importdisk 9000 bionic-server-cloudimg-amd64.img local-lvm

# finally attach the new disk to the VM as scsi drive
qm set 9000 --scsihw virtio-scsi-pci --scsi0 local-lvm:vm-9000-disk-1
Note Ubuntu Cloud-Init images require the virtio-scsi-pci controller type for SCSI drives.
gui-cloudinit-hardware.png
Add Cloud-Init CDROM drive

The next step is to configure a CDROM drive which will be used to pass the Cloud-Init data to the VM.

qm set 9000 --ide2 local-lvm:cloudinit

To be able to boot directly from the Cloud-Init image, set the bootdisk parameter to scsi0, and restrict BIOS to boot from disk only. This will speed up booting, because VM BIOS skips the testing for a bootable CDROM.

qm set 9000 --boot c --bootdisk scsi0

Also configure a serial console and use it as a display. Many Cloud-Init images rely on this, as it is an requirement for OpenStack images.

qm set 9000 --serial0 socket --vga serial0

In a last step, it is helpful to convert the VM into a template. From this template you can then quickly create linked clones. The deployment from VM templates is much faster than creating a full clone (copy).

qm template 9000

10.7.2. Deploying Cloud-Init Templates

gui-cloudinit-config.png

You can easily deploy such a template by cloning:

qm clone 9000 123 --name ubuntu2

Then configure the SSH public key used for authentication, and configure the IP setup:

qm set 123 --sshkey ~/.ssh/id_rsa.pub
qm set 123 --ipconfig0 ip=10.0.10.123/24,gw=10.0.10.1

You can also configure all the Cloud-Init options using a single command only. We have simply splitted the above example to separate the commands for reducing the line length. Also make sure to adopt the IP setup for your specific environment.

10.7.3. Cloud-Init specific Options

cipassword: <string>

Password to assign the user. Using this is generally not recommended. Use ssh keys instead. Also note that older cloud-init versions do not support hashed passwords.

citype: <configdrive2 | nocloud>

Specifies the cloud-init configuration format. The default depends on the configured operating system type (ostype. We use the nocloud format for Linux, and configdrive2 for windows.

ciuser: <string>

User name to change ssh keys and password for instead of the image’s configured default user.

ipconfig[n]: [gw=<GatewayIPv4>] [,gw6=<GatewayIPv6>] [,ip=<IPv4Format/CIDR>] [,ip6=<IPv6Format/CIDR>]

Specify IP addresses and gateways for the corresponding interface.

IP addresses use CIDR notation, gateways are optional but need an IP of the same type specified.

The special string dhcp can be used for IP addresses to use DHCP, in which case no explicit gateway should be provided. For IPv6 the special string auto can be used to use stateless autoconfiguration.

If cloud-init is enabled and neither an IPv4 nor an IPv6 address is specified, it defaults to using dhcp on IPv4.

gw=<GatewayIPv4>

Default gateway for IPv4 traffic.

Note Requires option(s): ip
gw6=<GatewayIPv6>

Default gateway for IPv6 traffic.

Note Requires option(s): ip6
ip=<IPv4Format/CIDR> (default = dhcp)

IPv4 address in CIDR format.

ip6=<IPv6Format/CIDR> (default = dhcp)

IPv6 address in CIDR format.

nameserver: <string>

Sets DNS server IP address for a container. Create will automatically use the setting from the host if neither searchdomain nor nameserver are set.

searchdomain: <string>

Sets DNS search domains for a container. Create will automatically use the setting from the host if neither searchdomain nor nameserver are set.

sshkeys: <string>

Setup public SSH keys (one key per line, OpenSSH format).

10.8. Managing Virtual Machines with qm

qm is the tool to manage Qemu/Kvm virtual machines on Proxmox VE. You can create and destroy virtual machines, and control execution (start/stop/suspend/resume). Besides that, you can use qm to set parameters in the associated config file. It is also possible to create and delete virtual disks.

10.8.1. CLI Usage Examples

Using an iso file uploaded on the local storage, create a VM with a 4 GB IDE disk on the local-lvm storage

qm create 300 -ide0 local-lvm:4 -net0 e1000 -cdrom local:iso/proxmox-mailgateway_2.1.iso

Start the new VM

qm start 300

Send a shutdown request, then wait until the VM is stopped.

qm shutdown 300 && qm wait 300

Same as above, but only wait for 40 seconds.

qm shutdown 300 && qm wait 300 -timeout 40

10.9. Configuration

VM configuration files are stored inside the Proxmox cluster file system, and can be accessed at /etc/pve/qemu-server/<VMID>.conf. Like other files stored inside /etc/pve/, they get automatically replicated to all other cluster nodes.

Note VMIDs < 100 are reserved for internal purposes, and VMIDs need to be unique cluster wide.
Example VM Configuration
cores: 1
sockets: 1
memory: 512
name: webmail
ostype: l26
bootdisk: virtio0
net0: e1000=EE:D2:28:5F:B6:3E,bridge=vmbr0
virtio0: local:vm-100-disk-1,size=32G

Those configuration files are simple text files, and you can edit them using a normal text editor (vi, nano, …). This is sometimes useful to do small corrections, but keep in mind that you need to restart the VM to apply such changes.

For that reason, it is usually better to use the qm command to generate and modify those files, or do the whole thing using the GUI. Our toolkit is smart enough to instantaneously apply most changes to running VM. This feature is called "hot plug", and there is no need to restart the VM in that case.

10.9.1. File Format

VM configuration files use a simple colon separated key/value format. Each line has the following format:

# this is a comment
OPTION: value

Blank lines in those files are ignored, and lines starting with a # character are treated as comments and are also ignored.

10.9.2. Snapshots

When you create a snapshot, qm stores the configuration at snapshot time into a separate snapshot section within the same configuration file. For example, after creating a snapshot called “testsnapshot”, your configuration file will look like this:

VM configuration with snapshot
memory: 512
swap: 512
parent: testsnaphot
...

[testsnaphot]
memory: 512
swap: 512
snaptime: 1457170803
...

There are a few snapshot related properties like parent and snaptime. The parent property is used to store the parent/child relationship between snapshots. snaptime is the snapshot creation time stamp (Unix epoch).

10.9.3. Options

acpi: <boolean> (default = 1)

Enable/disable ACPI.

agent: <boolean> (default = 0)

Enable/disable Qemu GuestAgent.

args: <string>

Arbitrary arguments passed to kvm, for example:

args: -no-reboot -no-hpet

Note this option is for experts only.
autostart: <boolean> (default = 0)

Automatic restart after crash (currently ignored).

balloon: <integer> (0 - N)

Amount of target RAM for the VM in MB. Using zero disables the ballon driver.

bios: <ovmf | seabios> (default = seabios)

Select BIOS implementation.

boot: [acdn]{1,4} (default = cdn)

Boot on floppy (a), hard disk (c), CD-ROM (d), or network (n).

bootdisk: (ide|sata|scsi|virtio)\d+

Enable booting from specified disk.

cdrom: <volume>

This is an alias for option -ide2

cipassword: <string>

cloud-init: Password to assign the user. Using this is generally not recommended. Use ssh keys instead. Also note that older cloud-init versions do not support hashed passwords.

citype: <configdrive2 | nocloud>

Specifies the cloud-init configuration format. The default depends on the configured operating system type (ostype. We use the nocloud format for Linux, and configdrive2 for windows.

ciuser: <string>

cloud-init: User name to change ssh keys and password for instead of the image’s configured default user.

cores: <integer> (1 - N) (default = 1)

The number of cores per socket.

cpu: [cputype=]<enum> [,flags=<+FLAG[;-FLAG...]>] [,hidden=<1|0>]

Emulated CPU type.

cputype=<486 | Broadwell | Broadwell-IBRS | Broadwell-noTSX | Broadwell-noTSX-IBRS | Conroe | EPYC | EPYC-IBPB | Haswell | Haswell-IBRS | Haswell-noTSX | Haswell-noTSX-IBRS | IvyBridge | IvyBridge-IBRS | Nehalem | Nehalem-IBRS | Opteron_G1 | Opteron_G2 | Opteron_G3 | Opteron_G4 | Opteron_G5 | Penryn | SandyBridge | SandyBridge-IBRS | Skylake-Client | Skylake-Client-IBRS | Skylake-Server | Skylake-Server-IBRS | Westmere | Westmere-IBRS | athlon | core2duo | coreduo | host | kvm32 | kvm64 | max | pentium | pentium2 | pentium3 | phenom | qemu32 | qemu64> (default = kvm64)

Emulated CPU type.

flags=<+FLAG[;-FLAG...]>

List of additional CPU flags separated by ;. Use +FLAG to enable, -FLAG to disable a flag. Currently supported flags: pcid, spec-ctrl.

hidden=<boolean> (default = 0)

Do not identify as a KVM virtual machine.

cpulimit: <number> (0 - 128) (default = 0)

Limit of CPU usage.

Note If the computer has 2 CPUs, it has total of 2 CPU time. Value 0 indicates no CPU limit.
cpuunits: <integer> (2 - 262144) (default = 1024)

CPU weight for a VM. Argument is used in the kernel fair scheduler. The larger the number is, the more CPU time this VM gets. Number is relative to weights of all the other running VMs.

description: <string>

Description for the VM. Only used on the configuration web interface. This is saved as comment inside the configuration file.

efidisk0: [file=]<volume> [,format=<enum>] [,size=<DiskSize>]

Configure a Disk for storing EFI vars

file=<volume>

The drive’s backing volume.

format=<cloop | cow | qcow | qcow2 | qed | raw | vmdk>

The drive’s backing file’s data format.

size=<DiskSize>

Disk size. This is purely informational and has no effect.

freeze: <boolean>

Freeze CPU at startup (use c monitor command to start execution).

hostpci[n]: [host=]<HOSTPCIID[;HOSTPCIID2...]> [,pcie=<1|0>] [,rombar=<1|0>] [,romfile=<string>] [,x-vga=<1|0>]

Map host PCI devices into guest.

Note This option allows direct access to host hardware. So it is no longer possible to migrate such machines - use with special care.
Caution Experimental! User reported problems with this option.
host=<HOSTPCIID[;HOSTPCIID2...]>

Host PCI device pass through. The PCI ID of a host’s PCI device or a list of PCI virtual functions of the host. HOSTPCIID syntax is:

bus:dev.func (hexadecimal numbers)

You can us the lspci command to list existing PCI devices.

pcie=<boolean> (default = 0)

Choose the PCI-express bus (needs the q35 machine model).

rombar=<boolean> (default = 1)

Specify whether or not the device’s ROM will be visible in the guest’s memory map.

romfile=<string>

Custom pci device rom filename (must be located in /usr/share/kvm/).

x-vga=<boolean> (default = 0)

Enable vfio-vga device support.

hotplug: <string> (default = network,disk,usb)

Selectively enable hotplug features. This is a comma separated list of hotplug features: network, disk, cpu, memory and usb. Use 0 to disable hotplug completely. Value 1 is an alias for the default network,disk,usb.

hugepages: <1024 | 2 | any>

Enable/disable hugepages memory.

ide[n]: [file=]<volume> [,aio=<native|threads>] [,backup=<1|0>] [,bps=<bps>] [,bps_max_length=<seconds>] [,bps_rd=<bps>] [,bps_rd_max_length=<seconds>] [,bps_wr=<bps>] [,bps_wr_max_length=<seconds>] [,cache=<enum>] [,cyls=<integer>] [,detect_zeroes=<1|0>] [,discard=<ignore|on>] [,format=<enum>] [,heads=<integer>] [,iops=<iops>] [,iops_max=<iops>] [,iops_max_length=<seconds>] [,iops_rd=<iops>] [,iops_rd_max=<iops>] [,iops_rd_max_length=<seconds>] [,iops_wr=<iops>] [,iops_wr_max=<iops>] [,iops_wr_max_length=<seconds>] [,mbps=<mbps>] [,mbps_max=<mbps>] [,mbps_rd=<mbps>] [,mbps_rd_max=<mbps>] [,mbps_wr=<mbps>] [,mbps_wr_max=<mbps>] [,media=<cdrom|disk>] [,model=<model>] [,replicate=<1|0>] [,rerror=<ignore|report|stop>] [,secs=<integer>] [,serial=<serial>] [,shared=<1|0>] [,size=<DiskSize>] [,snapshot=<1|0>] [,trans=<none|lba|auto>] [,werror=<enum>]

Use volume as IDE hard disk or CD-ROM (n is 0 to 3).

aio=<native | threads>

AIO type to use.

backup=<boolean>

Whether the drive should be included when making backups.

bps=<bps>

Maximum r/w speed in bytes per second.

bps_max_length=<seconds>

Maximum length of I/O bursts in seconds.

bps_rd=<bps>

Maximum read speed in bytes per second.

bps_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

bps_wr=<bps>

Maximum write speed in bytes per second.

bps_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

cache=<directsync | none | unsafe | writeback | writethrough>

The drive’s cache mode

cyls=<integer>

Force the drive’s physical geometry to have a specific cylinder count.

detect_zeroes=<boolean>

Controls whether to detect and try to optimize writes of zeroes.

discard=<ignore | on>

Controls whether to pass discard/trim requests to the underlying storage.

file=<volume>

The drive’s backing volume.

format=<cloop | cow | qcow | qcow2 | qed | raw | vmdk>

The drive’s backing file’s data format.

heads=<integer>

Force the drive’s physical geometry to have a specific head count.

iops=<iops>

Maximum r/w I/O in operations per second.

iops_max=<iops>

Maximum unthrottled r/w I/O pool in operations per second.

iops_max_length=<seconds>

Maximum length of I/O bursts in seconds.

iops_rd=<iops>

Maximum read I/O in operations per second.

iops_rd_max=<iops>

Maximum unthrottled read I/O pool in operations per second.

iops_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

iops_wr=<iops>

Maximum write I/O in operations per second.

iops_wr_max=<iops>

Maximum unthrottled write I/O pool in operations per second.

iops_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

mbps=<mbps>

Maximum r/w speed in megabytes per second.

mbps_max=<mbps>

Maximum unthrottled r/w pool in megabytes per second.

mbps_rd=<mbps>

Maximum read speed in megabytes per second.

mbps_rd_max=<mbps>

Maximum unthrottled read pool in megabytes per second.

mbps_wr=<mbps>

Maximum write speed in megabytes per second.

mbps_wr_max=<mbps>

Maximum unthrottled write pool in megabytes per second.

media=<cdrom | disk> (default = disk)

The drive’s media type.

model=<model>

The drive’s reported model name, url-encoded, up to 40 bytes long.

replicate=<boolean> (default = 1)

Whether the drive should considered for replication jobs.

rerror=<ignore | report | stop>

Read error action.

secs=<integer>

Force the drive’s physical geometry to have a specific sector count.

serial=<serial>

The drive’s reported serial number, url-encoded, up to 20 bytes long.

shared=<boolean> (default = 0)

Mark this locally-managed volume as available on all nodes.

Warning This option does not share the volume automatically, it assumes it is shared already!
size=<DiskSize>

Disk size. This is purely informational and has no effect.

snapshot=<boolean>

Controls qemu’s snapshot mode feature. If activated, changes made to the disk are temporary and will be discarded when the VM is shutdown.

trans=<auto | lba | none>

Force disk geometry bios translation mode.

werror=<enospc | ignore | report | stop>

Write error action.

ipconfig[n]: [gw=<GatewayIPv4>] [,gw6=<GatewayIPv6>] [,ip=<IPv4Format/CIDR>] [,ip6=<IPv6Format/CIDR>]

cloud-init: Specify IP addresses and gateways for the corresponding interface.

IP addresses use CIDR notation, gateways are optional but need an IP of the same type specified.

The special string dhcp can be used for IP addresses to use DHCP, in which case no explicit gateway should be provided. For IPv6 the special string auto can be used to use stateless autoconfiguration.

If cloud-init is enabled and neither an IPv4 nor an IPv6 address is specified, it defaults to using dhcp on IPv4.

gw=<GatewayIPv4>

Default gateway for IPv4 traffic.

Note Requires option(s): ip
gw6=<GatewayIPv6>

Default gateway for IPv6 traffic.

Note Requires option(s): ip6
ip=<IPv4Format/CIDR> (default = dhcp)

IPv4 address in CIDR format.

ip6=<IPv6Format/CIDR> (default = dhcp)

IPv6 address in CIDR format.

keyboard: <da | de | de-ch | en-gb | en-us | es | fi | fr | fr-be | fr-ca | fr-ch | hu | is | it | ja | lt | mk | nl | no | pl | pt | pt-br | sl | sv | tr>

Keybord layout for vnc server. Default is read from the /etc/pve/datacenter.cfg configuration file.It should not be necessary to set it.

kvm: <boolean> (default = 1)

Enable/disable KVM hardware virtualization.

localtime: <boolean>

Set the real time clock to local time. This is enabled by default if ostype indicates a Microsoft OS.

lock: <backup | migrate | rollback | snapshot>

Lock/unlock the VM.

machine: (pc|pc(-i440fx)?-\d+\.\d+(\.pxe)?|q35|pc-q35-\d+\.\d+(\.pxe)?)

Specific the Qemu machine type.

memory: <integer> (16 - N) (default = 512)

Amount of RAM for the VM in MB. This is the maximum available memory when you use the balloon device.

migrate_downtime: <number> (0 - N) (default = 0.1)

Set maximum tolerated downtime (in seconds) for migrations.

migrate_speed: <integer> (0 - N) (default = 0)

Set maximum speed (in MB/s) for migrations. Value 0 is no limit.

name: <string>

Set a name for the VM. Only used on the configuration web interface.

nameserver: <string>

cloud-init: Sets DNS server IP address for a container. Create will automatically use the setting from the host if neither searchdomain nor nameserver are set.

net[n]: [model=]<enum> [,bridge=<bridge>] [,firewall=<1|0>] [,link_down=<1|0>] [,macaddr=<XX:XX:XX:XX:XX:XX>] [,queues=<integer>] [,rate=<number>] [,tag=<integer>] [,trunks=<vlanid[;vlanid...]>] [,<model>=<macaddr>]

Specify network devices.

bridge=<bridge>

Bridge to attach the network device to. The Proxmox VE standard bridge is called vmbr0.

If you do not specify a bridge, we create a kvm user (NATed) network device, which provides DHCP and DNS services. The following addresses are used:

10.0.2.2   Gateway
10.0.2.3   DNS Server
10.0.2.4   SMB Server

The DHCP server assign addresses to the guest starting from 10.0.2.15.

firewall=<boolean>

Whether this interface should be protected by the firewall.

link_down=<boolean>

Whether this interface should be disconnected (like pulling the plug).

macaddr=<XX:XX:XX:XX:XX:XX>

MAC address. That address must be unique withing your network. This is automatically generated if not specified.

model=<e1000 | e1000-82540em | e1000-82544gc | e1000-82545em | i82551 | i82557b | i82559er | ne2k_isa | ne2k_pci | pcnet | rtl8139 | virtio | vmxnet3>

Network Card Model. The virtio model provides the best performance with very low CPU overhead. If your guest does not support this driver, it is usually best to use e1000.

queues=<integer> (0 - 16)

Number of packet queues to be used on the device.

rate=<number> (0 - N)

Rate limit in mbps (megabytes per second) as floating point number.

tag=<integer> (1 - 4094)

VLAN tag to apply to packets on this interface.

trunks=<vlanid[;vlanid...]>

VLAN trunks to pass through this interface.

numa: <boolean> (default = 0)

Enable/disable NUMA.

numa[n]: cpus=<id[-id];...> [,hostnodes=<id[-id];...>] [,memory=<number>] [,policy=<preferred|bind|interleave>]

NUMA topology.

cpus=<id[-id];...>

CPUs accessing this NUMA node.

hostnodes=<id[-id];...>

Host NUMA nodes to use.

memory=<number>

Amount of memory this NUMA node provides.

policy=<bind | interleave | preferred>

NUMA allocation policy.

onboot: <boolean> (default = 0)

Specifies whether a VM will be started during system bootup.

ostype: <l24 | l26 | other | solaris | w2k | w2k3 | w2k8 | win10 | win7 | win8 | wvista | wxp>

Specify guest operating system. This is used to enable special optimization/features for specific operating systems:

other

unspecified OS

wxp

Microsoft Windows XP

w2k

Microsoft Windows 2000

w2k3

Microsoft Windows 2003

w2k8

Microsoft Windows 2008

wvista

Microsoft Windows Vista

win7

Microsoft Windows 7

win8

Microsoft Windows 8/2012/2012r2

win10

Microsoft Windows 10/2016

l24

Linux 2.4 Kernel

l26

Linux 2.6/3.X Kernel

solaris

Solaris/OpenSolaris/OpenIndiania kernel

parallel[n]: /dev/parport\d+|/dev/usb/lp\d+

Map host parallel devices (n is 0 to 2).

Note This option allows direct access to host hardware. So it is no longer possible to migrate such machines - use with special care.
Caution Experimental! User reported problems with this option.
protection: <boolean> (default = 0)

Sets the protection flag of the VM. This will disable the remove VM and remove disk operations.

reboot: <boolean> (default = 1)

Allow reboot. If set to 0 the VM exit on reboot.

sata[n]: [file=]<volume> [,aio=<native|threads>] [,backup=<1|0>] [,bps=<bps>] [,bps_max_length=<seconds>] [,bps_rd=<bps>] [,bps_rd_max_length=<seconds>] [,bps_wr=<bps>] [,bps_wr_max_length=<seconds>] [,cache=<enum>] [,cyls=<integer>] [,detect_zeroes=<1|0>] [,discard=<ignore|on>] [,format=<enum>] [,heads=<integer>] [,iops=<iops>] [,iops_max=<iops>] [,iops_max_length=<seconds>] [,iops_rd=<iops>] [,iops_rd_max=<iops>] [,iops_rd_max_length=<seconds>] [,iops_wr=<iops>] [,iops_wr_max=<iops>] [,iops_wr_max_length=<seconds>] [,mbps=<mbps>] [,mbps_max=<mbps>] [,mbps_rd=<mbps>] [,mbps_rd_max=<mbps>] [,mbps_wr=<mbps>] [,mbps_wr_max=<mbps>] [,media=<cdrom|disk>] [,replicate=<1|0>] [,rerror=<ignore|report|stop>] [,secs=<integer>] [,serial=<serial>] [,shared=<1|0>] [,size=<DiskSize>] [,snapshot=<1|0>] [,trans=<none|lba|auto>] [,werror=<enum>]

Use volume as SATA hard disk or CD-ROM (n is 0 to 5).

aio=<native | threads>

AIO type to use.

backup=<boolean>

Whether the drive should be included when making backups.

bps=<bps>

Maximum r/w speed in bytes per second.

bps_max_length=<seconds>

Maximum length of I/O bursts in seconds.

bps_rd=<bps>

Maximum read speed in bytes per second.

bps_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

bps_wr=<bps>

Maximum write speed in bytes per second.

bps_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

cache=<directsync | none | unsafe | writeback | writethrough>

The drive’s cache mode

cyls=<integer>

Force the drive’s physical geometry to have a specific cylinder count.

detect_zeroes=<boolean>

Controls whether to detect and try to optimize writes of zeroes.

discard=<ignore | on>

Controls whether to pass discard/trim requests to the underlying storage.

file=<volume>

The drive’s backing volume.

format=<cloop | cow | qcow | qcow2 | qed | raw | vmdk>

The drive’s backing file’s data format.

heads=<integer>

Force the drive’s physical geometry to have a specific head count.

iops=<iops>

Maximum r/w I/O in operations per second.

iops_max=<iops>

Maximum unthrottled r/w I/O pool in operations per second.

iops_max_length=<seconds>

Maximum length of I/O bursts in seconds.

iops_rd=<iops>

Maximum read I/O in operations per second.

iops_rd_max=<iops>

Maximum unthrottled read I/O pool in operations per second.

iops_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

iops_wr=<iops>

Maximum write I/O in operations per second.

iops_wr_max=<iops>

Maximum unthrottled write I/O pool in operations per second.

iops_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

mbps=<mbps>

Maximum r/w speed in megabytes per second.

mbps_max=<mbps>

Maximum unthrottled r/w pool in megabytes per second.

mbps_rd=<mbps>

Maximum read speed in megabytes per second.

mbps_rd_max=<mbps>

Maximum unthrottled read pool in megabytes per second.

mbps_wr=<mbps>

Maximum write speed in megabytes per second.

mbps_wr_max=<mbps>

Maximum unthrottled write pool in megabytes per second.

media=<cdrom | disk> (default = disk)

The drive’s media type.

replicate=<boolean> (default = 1)

Whether the drive should considered for replication jobs.

rerror=<ignore | report | stop>

Read error action.

secs=<integer>

Force the drive’s physical geometry to have a specific sector count.

serial=<serial>

The drive’s reported serial number, url-encoded, up to 20 bytes long.

shared=<boolean> (default = 0)

Mark this locally-managed volume as available on all nodes.

Warning This option does not share the volume automatically, it assumes it is shared already!
size=<DiskSize>

Disk size. This is purely informational and has no effect.

snapshot=<boolean>

Controls qemu’s snapshot mode feature. If activated, changes made to the disk are temporary and will be discarded when the VM is shutdown.

trans=<auto | lba | none>

Force disk geometry bios translation mode.

werror=<enospc | ignore | report | stop>

Write error action.

scsi[n]: [file=]<volume> [,aio=<native|threads>] [,backup=<1|0>] [,bps=<bps>] [,bps_max_length=<seconds>] [,bps_rd=<bps>] [,bps_rd_max_length=<seconds>] [,bps_wr=<bps>] [,bps_wr_max_length=<seconds>] [,cache=<enum>] [,cyls=<integer>] [,detect_zeroes=<1|0>] [,discard=<ignore|on>] [,format=<enum>] [,heads=<integer>] [,iops=<iops>] [,iops_max=<iops>] [,iops_max_length=<seconds>] [,iops_rd=<iops>] [,iops_rd_max=<iops>] [,iops_rd_max_length=<seconds>] [,iops_wr=<iops>] [,iops_wr_max=<iops>] [,iops_wr_max_length=<seconds>] [,iothread=<1|0>] [,mbps=<mbps>] [,mbps_max=<mbps>] [,mbps_rd=<mbps>] [,mbps_rd_max=<mbps>] [,mbps_wr=<mbps>] [,mbps_wr_max=<mbps>] [,media=<cdrom|disk>] [,queues=<integer>] [,replicate=<1|0>] [,rerror=<ignore|report|stop>] [,scsiblock=<1|0>] [,secs=<integer>] [,serial=<serial>] [,shared=<1|0>] [,size=<DiskSize>] [,snapshot=<1|0>] [,trans=<none|lba|auto>] [,werror=<enum>]

Use volume as SCSI hard disk or CD-ROM (n is 0 to 13).

aio=<native | threads>

AIO type to use.

backup=<boolean>

Whether the drive should be included when making backups.

bps=<bps>

Maximum r/w speed in bytes per second.

bps_max_length=<seconds>

Maximum length of I/O bursts in seconds.

bps_rd=<bps>

Maximum read speed in bytes per second.

bps_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

bps_wr=<bps>

Maximum write speed in bytes per second.

bps_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

cache=<directsync | none | unsafe | writeback | writethrough>

The drive’s cache mode

cyls=<integer>

Force the drive’s physical geometry to have a specific cylinder count.

detect_zeroes=<boolean>

Controls whether to detect and try to optimize writes of zeroes.

discard=<ignore | on>

Controls whether to pass discard/trim requests to the underlying storage.

file=<volume>

The drive’s backing volume.

format=<cloop | cow | qcow | qcow2 | qed | raw | vmdk>

The drive’s backing file’s data format.

heads=<integer>

Force the drive’s physical geometry to have a specific head count.

iops=<iops>

Maximum r/w I/O in operations per second.

iops_max=<iops>

Maximum unthrottled r/w I/O pool in operations per second.

iops_max_length=<seconds>

Maximum length of I/O bursts in seconds.

iops_rd=<iops>

Maximum read I/O in operations per second.

iops_rd_max=<iops>

Maximum unthrottled read I/O pool in operations per second.

iops_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

iops_wr=<iops>

Maximum write I/O in operations per second.

iops_wr_max=<iops>

Maximum unthrottled write I/O pool in operations per second.

iops_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

iothread=<boolean>

Whether to use iothreads for this drive

mbps=<mbps>

Maximum r/w speed in megabytes per second.

mbps_max=<mbps>

Maximum unthrottled r/w pool in megabytes per second.

mbps_rd=<mbps>

Maximum read speed in megabytes per second.

mbps_rd_max=<mbps>

Maximum unthrottled read pool in megabytes per second.

mbps_wr=<mbps>

Maximum write speed in megabytes per second.

mbps_wr_max=<mbps>

Maximum unthrottled write pool in megabytes per second.

media=<cdrom | disk> (default = disk)

The drive’s media type.

queues=<integer> (2 - N)

Number of queues.

replicate=<boolean> (default = 1)

Whether the drive should considered for replication jobs.

rerror=<ignore | report | stop>

Read error action.

scsiblock=<boolean> (default = 0)

whether to use scsi-block for full passthrough of host block device

Warning can lead to I/O errors in combination with low memory or high memory fragmentation on host
secs=<integer>

Force the drive’s physical geometry to have a specific sector count.

serial=<serial>

The drive’s reported serial number, url-encoded, up to 20 bytes long.

shared=<boolean> (default = 0)

Mark this locally-managed volume as available on all nodes.

Warning This option does not share the volume automatically, it assumes it is shared already!
size=<DiskSize>

Disk size. This is purely informational and has no effect.

snapshot=<boolean>

Controls qemu’s snapshot mode feature. If activated, changes made to the disk are temporary and will be discarded when the VM is shutdown.

trans=<auto | lba | none>

Force disk geometry bios translation mode.

werror=<enospc | ignore | report | stop>

Write error action.

scsihw: <lsi | lsi53c810 | megasas | pvscsi | virtio-scsi-pci | virtio-scsi-single> (default = lsi)

SCSI controller model

searchdomain: <string>

cloud-init: Sets DNS search domains for a container. Create will automatically use the setting from the host if neither searchdomain nor nameserver are set.

serial[n]: (/dev/.+|socket)

Create a serial device inside the VM (n is 0 to 3), and pass through a host serial device (i.e. /dev/ttyS0), or create a unix socket on the host side (use qm terminal to open a terminal connection).

Note If you pass through a host serial device, it is no longer possible to migrate such machines - use with special care.
Caution Experimental! User reported problems with this option.
shares: <integer> (0 - 50000) (default = 1000)

Amount of memory shares for auto-ballooning. The larger the number is, the more memory this VM gets. Number is relative to weights of all other running VMs. Using zero disables auto-ballooning. Auto-ballooning is done by pvestatd.

smbios1: [family=<string>] [,manufacturer=<string>] [,product=<string>] [,serial=<string>] [,sku=<string>] [,uuid=<UUID>] [,version=<string>]

Specify SMBIOS type 1 fields.

family=<string>

Set SMBIOS1 family string.

manufacturer=<string>

Set SMBIOS1 manufacturer.

product=<string>

Set SMBIOS1 product ID.

serial=<string>

Set SMBIOS1 serial number.

sku=<string>

Set SMBIOS1 SKU string.

uuid=<UUID>

Set SMBIOS1 UUID.

version=<string>

Set SMBIOS1 version.

smp: <integer> (1 - N) (default = 1)

The number of CPUs. Please use option -sockets instead.

sockets: <integer> (1 - N) (default = 1)

The number of CPU sockets.

sshkeys: <string>

cloud-init: Setup public SSH keys (one key per line, OpenSSH format).

startdate: (now | YYYY-MM-DD | YYYY-MM-DDTHH:MM:SS) (default = now)

Set the initial date of the real time clock. Valid format for date are: now or 2006-06-17T16:01:21 or 2006-06-17.

startup: `[[order=]\d+] [,up=\d+] [,down=\d+] `

Startup and shutdown behavior. Order is a non-negative number defining the general startup order. Shutdown in done with reverse ordering. Additionally you can set the up or down delay in seconds, which specifies a delay to wait before the next VM is started or stopped.

tablet: <boolean> (default = 1)

Enable/disable the USB tablet device. This device is usually needed to allow absolute mouse positioning with VNC. Else the mouse runs out of sync with normal VNC clients. If you’re running lots of console-only guests on one host, you may consider disabling this to save some context switches. This is turned off by default if you use spice (-vga=qxl).

tdf: <boolean> (default = 0)

Enable/disable time drift fix.

template: <boolean> (default = 0)

Enable/disable Template.

unused[n]: <string>

Reference to unused volumes. This is used internally, and should not be modified manually.

usb[n]: [host=]<HOSTUSBDEVICE|spice> [,usb3=<1|0>]

Configure an USB device (n is 0 to 4).

host=<HOSTUSBDEVICE|spice>

The Host USB device or port or the value spice. HOSTUSBDEVICE syntax is:

'bus-port(.port)*' (decimal numbers) or
'vendor_id:product_id' (hexadeciaml numbers) or
'spice'

You can use the lsusb -t command to list existing usb devices.

Note This option allows direct access to host hardware. So it is no longer possible to migrate such machines - use with special care.

The value spice can be used to add a usb redirection devices for spice.

usb3=<boolean> (default = 0)

Specifies whether if given host option is a USB3 device or port (this does currently not work reliably with spice redirection and is then ignored).

vcpus: <integer> (1 - N) (default = 0)

Number of hotplugged vcpus.

vga: <cirrus | qxl | qxl2 | qxl3 | qxl4 | serial0 | serial1 | serial2 | serial3 | std | vmware>

Select the VGA type. If you want to use high resolution modes (>= 1280x1024x16) then you should use the options std or vmware. Default is std for win8/win7/w2k8, and cirrus for other OS types. The qxl option enables the SPICE display sever. For win* OS you can select how many independent displays you want, Linux guests can add displays them self. You can also run without any graphic card, using a serial device as terminal.

virtio[n]: [file=]<volume> [,aio=<native|threads>] [,backup=<1|0>] [,bps=<bps>] [,bps_max_length=<seconds>] [,bps_rd=<bps>] [,bps_rd_max_length=<seconds>] [,bps_wr=<bps>] [,bps_wr_max_length=<seconds>] [,cache=<enum>] [,cyls=<integer>] [,detect_zeroes=<1|0>] [,discard=<ignore|on>] [,format=<enum>] [,heads=<integer>] [,iops=<iops>] [,iops_max=<iops>] [,iops_max_length=<seconds>] [,iops_rd=<iops>] [,iops_rd_max=<iops>] [,iops_rd_max_length=<seconds>] [,iops_wr=<iops>] [,iops_wr_max=<iops>] [,iops_wr_max_length=<seconds>] [,iothread=<1|0>] [,mbps=<mbps>] [,mbps_max=<mbps>] [,mbps_rd=<mbps>] [,mbps_rd_max=<mbps>] [,mbps_wr=<mbps>] [,mbps_wr_max=<mbps>] [,media=<cdrom|disk>] [,replicate=<1|0>] [,rerror=<ignore|report|stop>] [,secs=<integer>] [,serial=<serial>] [,shared=<1|0>] [,size=<DiskSize>] [,snapshot=<1|0>] [,trans=<none|lba|auto>] [,werror=<enum>]

Use volume as VIRTIO hard disk (n is 0 to 15).

aio=<native | threads>

AIO type to use.

backup=<boolean>

Whether the drive should be included when making backups.

bps=<bps>

Maximum r/w speed in bytes per second.

bps_max_length=<seconds>

Maximum length of I/O bursts in seconds.

bps_rd=<bps>

Maximum read speed in bytes per second.

bps_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

bps_wr=<bps>

Maximum write speed in bytes per second.

bps_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

cache=<directsync | none | unsafe | writeback | writethrough>

The drive’s cache mode

cyls=<integer>

Force the drive’s physical geometry to have a specific cylinder count.

detect_zeroes=<boolean>

Controls whether to detect and try to optimize writes of zeroes.

discard=<ignore | on>

Controls whether to pass discard/trim requests to the underlying storage.

file=<volume>

The drive’s backing volume.

format=<cloop | cow | qcow | qcow2 | qed | raw | vmdk>

The drive’s backing file’s data format.

heads=<integer>

Force the drive’s physical geometry to have a specific head count.

iops=<iops>

Maximum r/w I/O in operations per second.

iops_max=<iops>

Maximum unthrottled r/w I/O pool in operations per second.

iops_max_length=<seconds>

Maximum length of I/O bursts in seconds.

iops_rd=<iops>

Maximum read I/O in operations per second.

iops_rd_max=<iops>

Maximum unthrottled read I/O pool in operations per second.

iops_rd_max_length=<seconds>

Maximum length of read I/O bursts in seconds.

iops_wr=<iops>

Maximum write I/O in operations per second.

iops_wr_max=<iops>

Maximum unthrottled write I/O pool in operations per second.

iops_wr_max_length=<seconds>

Maximum length of write I/O bursts in seconds.

iothread=<boolean>

Whether to use iothreads for this drive

mbps=<mbps>

Maximum r/w speed in megabytes per second.

mbps_max=<mbps>

Maximum unthrottled r/w pool in megabytes per second.

mbps_rd=<mbps>

Maximum read speed in megabytes per second.

mbps_rd_max=<mbps>

Maximum unthrottled read pool in megabytes per second.

mbps_wr=<mbps>

Maximum write speed in megabytes per second.

mbps_wr_max=<mbps>

Maximum unthrottled write pool in megabytes per second.

media=<cdrom | disk> (default = disk)

The drive’s media type.

replicate=<boolean> (default = 1)

Whether the drive should considered for replication jobs.

rerror=<ignore | report | stop>

Read error action.

secs=<integer>

Force the drive’s physical geometry to have a specific sector count.

serial=<serial>

The drive’s reported serial number, url-encoded, up to 20 bytes long.

shared=<boolean> (default = 0)

Mark this locally-managed volume as available on all nodes.

Warning This option does not share the volume automatically, it assumes it is shared already!
size=<DiskSize>

Disk size. This is purely informational and has no effect.

snapshot=<boolean>

Controls qemu’s snapshot mode feature. If activated, changes made to the disk are temporary and will be discarded when the VM is shutdown.

trans=<auto | lba | none>

Force disk geometry bios translation mode.

werror=<enospc | ignore | report | stop>

Write error action.

vmstatestorage: <string>

Default storage for VM state volumes/files.

watchdog: [[model=]<i6300esb|ib700>] [,action=<enum>]

Create a virtual hardware watchdog device. Once enabled (by a guest action), the watchdog must be periodically polled by an agent inside the guest or else the watchdog will reset the guest (or execute the respective action specified)

action=<debug | none | pause | poweroff | reset | shutdown>

The action to perform if after activation the guest fails to poll the watchdog in time.

model=<i6300esb | ib700> (default = i6300esb)

Watchdog type to emulate.

10.10. Locks

Online migrations, snapshots and backups (vzdump) set a lock to prevent incompatible concurrent actions on the affected VMs. Sometimes you need to remove such a lock manually (e.g., after a power failure).

qm unlock <vmid>
Caution Only do that if you are sure the action which set the lock is no longer running.

11. Proxmox Container Toolkit

Containers are a lightweight alternative to fully virtualized VMs. Instead of emulating a complete Operating System (OS), containers simply use the OS of the host they run on. This implies that all containers use the same kernel, and that they can access resources from the host directly.

This is great because containers do not waste CPU power nor memory due to kernel emulation. Container run-time costs are close to zero and usually negligible. But there are also some drawbacks you need to consider:

  • You can only run Linux based OS inside containers, i.e. it is not possible to run FreeBSD or MS Windows inside.

  • For security reasons, access to host resources needs to be restricted. This is done with AppArmor, SecComp filters and other kernel features. Be prepared that some syscalls are not allowed inside containers.

Proxmox VE uses LXC as underlying container technology. We consider LXC as low-level library, which provides countless options. It would be too difficult to use those tools directly. Instead, we provide a small wrapper called pct, the "Proxmox Container Toolkit".

The toolkit is tightly coupled with Proxmox VE. That means that it is aware of the cluster setup, and it can use the same network and storage resources as fully virtualized VMs. You can even use the Proxmox VE firewall, or manage containers using the HA framework.

Our primary goal is to offer an environment as one would get from a VM, but without the additional overhead. We call this "System Containers".

Note If you want to run micro-containers (with docker, rkt, …), it is best to run them inside a VM.

11.1. Technology Overview

  • LXC (https://linuxcontainers.org/)

  • Integrated into Proxmox VE graphical user interface (GUI)

  • Easy to use command line tool pct

  • Access via Proxmox VE REST API

  • lxcfs to provide containerized /proc file system

  • AppArmor/Seccomp to improve security

  • CRIU: for live migration (planned)

  • Use latest available kernels (4.4.X)

  • Image based deployment (templates)

  • Use Proxmox VE storage library

  • Container setup from host (network, DNS, storage, …)

11.2. Security Considerations

Containers use the same kernel as the host, so there is a big attack surface for malicious users. You should consider this fact if you provide containers to totally untrusted people. In general, fully virtualized VMs provide better isolation.

The good news is that LXC uses many kernel security features like AppArmor, CGroups and PID and user namespaces, which makes containers usage quite secure.

11.3. Guest Operating System Configuration

We normally try to detect the operating system type inside the container, and then modify some files inside the container to make them work as expected. Here is a short list of things we do at container startup:

set /etc/hostname

to set the container name

modify /etc/hosts

to allow lookup of the local hostname

network setup

pass the complete network setup to the container

configure DNS

pass information about DNS servers

adapt the init system

for example, fix the number of spawned getty processes

set the root password

when creating a new container

rewrite ssh_host_keys

so that each container has unique keys

randomize crontab

so that cron does not start at the same time on all containers

Changes made by Proxmox VE are enclosed by comment markers:

# --- BEGIN PVE ---
<data>
# --- END PVE ---

Those markers will be inserted at a reasonable location in the file. If such a section already exists, it will be updated in place and will not be moved.

Modification of a file can be prevented by adding a .pve-ignore. file for it. For instance, if the file /etc/.pve-ignore.hosts exists then the /etc/hosts file will not be touched. This can be a simple empty file created via:

# touch /etc/.pve-ignore.hosts

Most modifications are OS dependent, so they differ between different distributions and versions. You can completely disable modifications by manually setting the ostype to unmanaged.

OS type detection is done by testing for certain files inside the container:

Ubuntu

inspect /etc/lsb-release (DISTRIB_ID=Ubuntu)

Debian

test /etc/debian_version

Fedora

test /etc/fedora-release

RedHat or CentOS

test /etc/redhat-release

ArchLinux

test /etc/arch-release

Alpine

test /etc/alpine-release

Gentoo

test /etc/gentoo-release

Note Container start fails if the configured ostype differs from the auto detected type.

11.4. Container Images

Container images, sometimes also referred to as “templates” or “appliances”, are tar archives which contain everything to run a container. You can think of it as a tidy container backup. Like most modern container toolkits, pct uses those images when you create a new container, for example:

pct create 999 local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz

Proxmox VE itself ships a set of basic templates for most common operating systems, and you can download them using the pveam (short for Proxmox VE Appliance Manager) command line utility. You can also download TurnKey Linux containers using that tool (or the graphical user interface).

Our image repositories contain a list of available images, and there is a cron job run each day to download that list. You can trigger that update manually with:

pveam update

After that you can view the list of available images using:

pveam available

You can restrict this large list by specifying the section you are interested in, for example basic system images:

List available system images
# pveam available --section system
system          archlinux-base_2015-24-29-1_x86_64.tar.gz
system          centos-7-default_20160205_amd64.tar.xz
system          debian-6.0-standard_6.0-7_amd64.tar.gz
system          debian-7.0-standard_7.0-3_amd64.tar.gz
system          debian-8.0-standard_8.0-1_amd64.tar.gz
system          ubuntu-12.04-standard_12.04-1_amd64.tar.gz
system          ubuntu-14.04-standard_14.04-1_amd64.tar.gz
system          ubuntu-15.04-standard_15.04-1_amd64.tar.gz
system          ubuntu-15.10-standard_15.10-1_amd64.tar.gz

Before you can use such a template, you need to download them into one of your storages. You can simply use storage local for that purpose. For clustered installations, it is preferred to use a shared storage so that all nodes can access those images.

pveam download local debian-8.0-standard_8.0-1_amd64.tar.gz

You are now ready to create containers using that image, and you can list all downloaded images on storage local with:

# pveam list local
local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz  190.20MB

The above command shows you the full Proxmox VE volume identifiers. They include the storage name, and most other Proxmox VE commands can use them. For example you can delete that image later with:

pveam remove local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz

11.5. Container Storage

Traditional containers use a very simple storage model, only allowing a single mount point, the root file system. This was further restricted to specific file system types like ext4 and nfs. Additional mounts are often done by user provided scripts. This turned out to be complex and error prone, so we try to avoid that now.

Our new LXC based container model is more flexible regarding storage. First, you can have more than a single mount point. This allows you to choose a suitable storage for each application. For example, you can use a relatively slow (and thus cheap) storage for the container root file system. Then you can use a second mount point to mount a very fast, distributed storage for your database application. See section Mount Points for further details.

The second big improvement is that you can use any storage type supported by the Proxmox VE storage library. That means that you can store your containers on local lvmthin or zfs, shared iSCSI storage, or even on distributed storage systems like ceph. It also enables us to use advanced storage features like snapshots and clones. vzdump can also use the snapshot feature to provide consistent container backups.

Last but not least, you can also mount local devices directly, or mount local directories using bind mounts. That way you can access local storage inside containers with zero overhead. Such bind mounts also provide an easy way to share data between different containers.

11.5.1. FUSE Mounts

Warning Because of existing issues in the Linux kernel’s freezer subsystem the usage of FUSE mounts inside a container is strongly advised against, as containers need to be frozen for suspend or snapshot mode backups.

If FUSE mounts cannot be replaced by other mounting mechanisms or storage technologies, it is possible to establish the FUSE mount on the Proxmox host and use a bind mount point to make it accessible inside the container.

11.5.2. Using Quotas Inside Containers

Quotas allow to set limits inside a container for the amount of disk space that each user can use. This only works on ext4 image based storage types and currently does not work with unprivileged containers.

Activating the quota option causes the following mount options to be used for a mount point: usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0

This allows quotas to be used like you would on any other system. You can initialize the /aquota.user and /aquota.group files by running

quotacheck -cmug /
quotaon /

and edit the quotas via the edquota command. Refer to the documentation of the distribution running inside the container for details.

Note You need to run the above commands for every mount point by passing the mount point’s path instead of just /.

11.5.3. Using ACLs Inside Containers

The standard Posix Access Control Lists are also available inside containers. ACLs allow you to set more detailed file ownership than the traditional user/ group/others model.

11.5.4. Backup of Containers mount points

By default additional mount points besides the Root Disk mount point are not included in backups. You can reverse this default behavior by setting the Backup option on a mount point.

11.5.5. Replication of Containers mount points

By default additional mount points are replicated when the Root Disk is replicated. If you want the Proxmox VE storage replication mechanism to skip a mount point when starting a replication job, you can set the Skip replication option on that mount point.
As of Proxmox VE 5.0, replication requires a storage of type zfspool, so adding a mount point to a different type of storage when the container has replication configured requires to Skip replication for that mount point.

11.6. Container Settings

11.6.1. General Settings

gui-create-ct-general.png

General settings of a container include

  • the Node : the physical server on which the container will run

  • the CT ID: a unique number in this Proxmox VE installation used to identify your container

  • Hostname: the hostname of the container

  • Resource Pool: a logical group of containers and VMs

  • Password: the root password of the container

  • SSH Public Key: a public key for connecting to the root account over SSH

  • Unprivileged container: this option allows to choose at creation time if you want to create a privileged or unprivileged container.

Privileged Containers

Security is done by dropping capabilities, using mandatory access control (AppArmor), SecComp filters and namespaces. The LXC team considers this kind of container as unsafe, and they will not consider new container escape exploits to be security issues worthy of a CVE and quick fix. So you should use this kind of containers only inside a trusted environment, or when no untrusted task is running as root in the container.

Unprivileged Containers

This kind of containers use a new kernel feature called user namespaces. The root UID 0 inside the container is mapped to an unprivileged user outside the container. This means that most security issues (container escape, resource abuse, …) in those containers will affect a random unprivileged user, and so would be a generic kernel security bug rather than an LXC issue. The LXC team thinks unprivileged containers are safe by design.

Note If the container uses systemd as an init system, please be aware the systemd version running inside the container should be equal or greater than 220.

11.6.2. CPU

gui-create-ct-cpu.png

You can restrict the number of visible CPUs inside the container using the cores option. This is implemented using the Linux cpuset cgroup (control group). A special task inside pvestatd tries to distribute running containers among available CPUs. You can view the assigned CPUs using the following command:

# pct cpusets
 ---------------------
 102:              6 7
 105:      2 3 4 5
 108:  0 1
 ---------------------

Containers use the host kernel directly, so all task inside a container are handled by the host CPU scheduler. Proxmox VE uses the Linux CFS (Completely Fair Scheduler) scheduler by default, which has additional bandwidth control options.

cpulimit:

You can use this option to further limit assigned CPU time. Please note that this is a floating point number, so it is perfectly valid to assign two cores to a container, but restrict overall CPU consumption to half a core.

cores: 2
cpulimit: 0.5
cpuunits:

This is a relative weight passed to the kernel scheduler. The larger the number is, the more CPU time this container gets. Number is relative to the weights of all the other running containers. The default is 1024. You can use this setting to prioritize some containers.

11.6.3. Memory

gui-create-ct-memory.png

Container memory is controlled using the cgroup memory controller.

memory:

Limit overall memory usage. This corresponds to the memory.limit_in_bytes cgroup setting.

swap:

Allows the container to use additional swap memory from the host swap space. This corresponds to the memory.memsw.limit_in_bytes cgroup setting, which is set to the sum of both value (memory + swap).

11.6.4. Mount Points

gui-create-ct-root-disk.png

The root mount point is configured with the rootfs property, and you can configure up to 10 additional mount points. The corresponding options are called mp0 to mp9, and they can contain the following setting:

rootfs: [volume=]<volume> [,acl=<1|0>] [,quota=<1|0>] [,replicate=<1|0>] [,ro=<1|0>] [,shared=<1|0>] [,size=<DiskSize>]

Use volume as container root. See below for a detailed description of all options.

mp[n]: [volume=]<volume> ,mp=<Path> [,acl=<1|0>] [,backup=<1|0>] [,quota=<1|0>] [,replicate=<1|0>] [,ro=<1|0>] [,shared=<1|0>] [,size=<DiskSize>]

Use volume as container mount point.

acl=<boolean>

Explicitly enable or disable ACL support.

backup=<boolean>

Whether to include the mount point in backups (only used for volume mount points).

mp=<Path>

Path to the mount point as seen from inside the container.

Note Must not contain any symlinks for security reasons.
quota=<boolean>

Enable user quotas inside the container (not supported with zfs subvolumes)

replicate=<boolean> (default = 1)

Will include this volume to a storage replica job.

ro=<boolean>

Read-only mount point

shared=<boolean> (default = 0)

Mark this non-volume mount point as available on all nodes.

Warning This option does not share the mount point automatically, it assumes it is shared already!
size=<DiskSize>

Volume size (read only value).

volume=<volume>

Volume, device or directory to mount into the container.

Currently there are basically three types of mount points: storage backed mount points, bind mounts and device mounts.

Typical container rootfs configuration
rootfs: thin1:base-100-disk-1,size=8G
Storage Backed Mount Points

Storage backed mount points are managed by the Proxmox VE storage subsystem and come in three different flavors:

  • Image based: these are raw images containing a single ext4 formatted file system.

  • ZFS subvolumes: these are technically bind mounts, but with managed storage, and thus allow resizing and snapshotting.

  • Directories: passing size=0 triggers a special case where instead of a raw image a directory is created.

Note The special option syntax STORAGE_ID:SIZE_IN_GB for storage backed mount point volumes will automatically allocate a volume of the specified size on the specified storage. E.g., calling pct set 100 -mp0 thin1:10,mp=/path/in/container will allocate a 10GB volume on the storage thin1 and replace the volume ID place holder 10 with the allocated volume ID.
Bind Mount Points

Bind mounts allow you to access arbitrary directories from your Proxmox VE host inside a container. Some potential use cases are:

  • Accessing your home directory in the guest

  • Accessing an USB device directory in the guest

  • Accessing an NFS mount from the host in the guest

Bind mounts are considered to not be managed by the storage subsystem, so you cannot make snapshots or deal with quotas from inside the container. With unprivileged containers you might run into permission problems caused by the user mapping and cannot use ACLs.

Note The contents of bind mount points are not backed up when using vzdump.
Warning For security reasons, bind mounts should only be established using source directories especially reserved for this purpose, e.g., a directory hierarchy under /mnt/bindmounts. Never bind mount system directories like /, /var or /etc into a container - this poses a great security risk.
Note The bind mount source path must not contain any symlinks.

For example, to make the directory /mnt/bindmounts/shared accessible in the container with ID 100 under the path /shared, use a configuration line like mp0: /mnt/bindmounts/shared,mp=/shared in /etc/pve/lxc/100.conf. Alternatively, use pct set 100 -mp0 /mnt/bindmounts/shared,mp=/shared to achieve the same result.

Device Mount Points

Device mount points allow to mount block devices of the host directly into the container. Similar to bind mounts, device mounts are not managed by Proxmox VE’s storage subsystem, but the quota and acl options will be honored.

Note Device mount points should only be used under special circumstances. In most cases a storage backed mount point offers the same performance and a lot more features.
Note The contents of device mount points are not backed up when using vzdump.

11.6.5. Network

gui-create-ct-network.png

You can configure up to 10 network interfaces for a single container. The corresponding options are called net0 to net9, and they can contain the following setting:

net[n]: name=<string> [,bridge=<bridge>] [,firewall=<1|0>] [,gw=<GatewayIPv4>] [,gw6=<GatewayIPv6>] [,hwaddr=<XX:XX:XX:XX:XX:XX>] [,ip=<(IPv4/CIDR|dhcp|manual)>] [,ip6=<(IPv6/CIDR|auto|dhcp|manual)>] [,mtu=<integer>] [,rate=<mbps>] [,tag=<integer>] [,trunks=<vlanid[;vlanid...]>] [,type=<veth>]

Specifies network interfaces for the container.

bridge=<bridge>

Bridge to attach the network device to.

firewall=<boolean>

Controls whether this interface’s firewall rules should be used.

gw=<GatewayIPv4>

Default gateway for IPv4 traffic.

gw6=<GatewayIPv6>

Default gateway for IPv6 traffic.

hwaddr=<XX:XX:XX:XX:XX:XX>

The interface MAC address. This is dynamically allocated by default, but you can set that statically if needed, for example to always have the same link-local IPv6 address. (lxc.network.hwaddr)

ip=<(IPv4/CIDR|dhcp|manual)>

IPv4 address in CIDR format.

ip6=<(IPv6/CIDR|auto|dhcp|manual)>

IPv6 address in CIDR format.

mtu=<integer> (64 - N)

Maximum transfer unit of the interface. (lxc.network.mtu)

name=<string>

Name of the network device as seen from inside the container. (lxc.network.name)

rate=<mbps>

Apply rate limiting to the interface

tag=<integer> (1 - 4094)

VLAN tag for this interface.

trunks=<vlanid[;vlanid...]>

VLAN ids to pass through the interface

type=<veth>

Network interface type.

11.6.6. Automatic Start and Shutdown of Containers

After creating your containers, you probably want them to start automatically when the host system boots. For this you need to select the option Start at boot from the Options Tab of your container in the web interface, or set it with the following command:

pct set <ctid> -onboot 1
gui-qemu-edit-start-order.png
Start and Shutdown Order

If you want to fine tune the boot order of your containers, you can use the following parameters :

  • Start/Shutdown order: Defines the start order priority. E.g. set it to 1 if you want the CT to be the first to be started. (We use the reverse startup order for shutdown, so a container with a start order of 1 would be the last to be shut down)

  • Startup delay: Defines the interval between this container start and subsequent containers starts . E.g. set it to 240 if you want to wait 240 seconds before starting other containers.

  • Shutdown timeout: Defines the duration in seconds Proxmox VE should wait for the container to be offline after issuing a shutdown command. By default this value is set to 60, which means that Proxmox VE will issue a shutdown request, wait 60s for the machine to be offline, and if after 60s the machine is still online will notify that the shutdown action failed.

Please note that containers without a Start/Shutdown order parameter will always start after those where the parameter is set, and this parameter only makes sense between the machines running locally on a host, and not cluster-wide.

11.7. Backup and Restore

11.7.1. Container Backup

It is possible to use the vzdump tool for container backup. Please refer to the vzdump manual page for details.

11.7.2. Restoring Container Backups

Restoring container backups made with vzdump is possible using the pct restore command. By default, pct restore will attempt to restore as much of the backed up container configuration as possible. It is possible to override the backed up configuration by manually setting container options on the command line (see the pct manual page for details).

Note pvesm extractconfig can be used to view the backed up configuration contained in a vzdump archive.

There are two basic restore modes, only differing by their handling of mount points:

“Simple” Restore Mode

If neither the rootfs parameter nor any of the optional mpX parameters are explicitly set, the mount point configuration from the backed up configuration file is restored using the following steps:

  1. Extract mount points and their options from backup

  2. Create volumes for storage backed mount points (on storage provided with the storage parameter, or default local storage if unset)

  3. Extract files from backup archive

  4. Add bind and device mount points to restored configuration (limited to root user)

Note Since bind and device mount points are never backed up, no files are restored in the last step, but only the configuration options. The assumption is that such mount points are either backed up with another mechanism (e.g., NFS space that is bind mounted into many containers), or not intended to be backed up at all.

This simple mode is also used by the container restore operations in the web interface.

“Advanced” Restore Mode

By setting the rootfs parameter (and optionally, any combination of mpX parameters), the pct restore command is automatically switched into an advanced mode. This advanced mode completely ignores the rootfs and mpX configuration options contained in the backup archive, and instead only uses the options explicitly provided as parameters.

This mode allows flexible configuration of mount point settings at restore time, for example:

  • Set target storages, volume sizes and other options for each mount point individually

  • Redistribute backed up files according to new mount point scheme

  • Restore to device and/or bind mount points (limited to root user)

11.8. Managing Containers with pc