Difference between revisions of "Linux Container"

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[[Category:Reference Documentation]]
 
[[Category:Reference Documentation]]
 
<pvehide>
 
<pvehide>
−
Containers are a lightweight alternative to fully virtualized
+
Containers are a lightweight alternative to fully virtualized machines (VMs).
−
VMs. Instead of emulating a complete Operating System (OS), containers
+
They use the kernel of the host system that they run on, instead of emulating a
−
simply use the OS of the host they run on. This implies that all
+
full operating system (OS). This means that containers can access resources on
−
containers use the same kernel, and that they can access resources
+
the host system directly.
−
from the host directly.
+
The runtime costs for containers is low, usually negligible. However, there are
−
This is great because containers do not waste CPU power nor memory due
+
some drawbacks that need be considered:
−
to kernel emulation. Container run-time costs are close to zero and
+
Only Linux distributions can be run in Proxmox Containers. It is not possible to run
−
usually negligible. But there are also some drawbacks you need to
+
  other operating systems like, for example, FreeBSD or Microsoft Windows
−
consider:
+
  inside a container.
−
You can only run Linux based OS inside containers, i.e. it is not
+
For security reasons, access to host resources needs to be restricted.
−
  possible to run FreeBSD or MS Windows inside.
+
   Therefore, containers run in their own separate namespaces. Additionally some
−
For security reasons, access to host resources needs to be
+
  syscalls (user space requests to the Linux kernel) are not allowed within containers.
−
  restricted. This is done with AppArmor, SecComp filters and other
+
Proxmox VE uses Linux Containers (LXC) as its underlying
−
   kernel features. Be prepared that some syscalls are not allowed
+
container technology. The &#8220;Proxmox Container Toolkit&#8221; (pct) simplifies the
−
  inside containers.
+
usage and management of LXC, by providing an interface that abstracts
−
Proxmox VE uses LXC as underlying container
+
complex tasks.
−
technology. We consider LXC as low-level library, which provides
+
Containers are tightly integrated with Proxmox VE. This means that they are aware of
−
countless options. It would be too difficult to use those tools
+
the cluster setup, and they can use the same network and storage resources as
−
directly. Instead, we provide a small wrapper called pct, the
+
virtual machines. You can also use the Proxmox VE firewall, or manage containers
−
"Proxmox Container Toolkit".
+
using the HA framework.
−
The toolkit is tightly coupled with Proxmox VE. That means that it is aware
+
Our primary goal is to offer an environment that provides the benefits of using a
−
of the cluster setup, and it can use the same network and storage
+
VM, but without the additional overhead. This means that Proxmox Containers can
−
resources as fully virtualized VMs. You can even use the Proxmox VE
+
be categorized as &#8220;System Containers&#8221;, rather than &#8220;Application Containers&#8221;.
−
firewall, or manage containers using the HA framework.
+
If you want to run application containers, for example, Docker images, it
−
Our primary goal is to offer an environment as one would get from a
+
is recommended that you run them inside a Proxmox Qemu VM. This will give you
−
VM, but without the additional overhead. We call this "System
+
all the advantages of application containerization, while also providing the
−
Containers".
+
benefits that VMs offer, such as strong isolation from the host and the ability
−
If you want to run micro-containers (with docker, rkt, &#8230;), it
+
to live-migrate, which otherwise isn&#8217;t possible with containers.
−
is best to run them inside a VM.
+
Technology Overview
 +
LXC (https://linuxcontainers.org/)
 +
Integrated into Proxmox VE graphical web user interface (GUI)
 +
Easy to use command line tool pct
 +
Access via Proxmox VE REST API
 +
lxcfs to provide containerized /proc file system
 +
Control groups (cgroups) for resource isolation and limitation
 +
AppArmor and seccomp to improve security
 +
Modern Linux kernels
 +
Image based deployment (templates)
 +
Uses Proxmox VE storage library
 +
Container setup from host (network, DNS, storage, etc.)
 +
Supported Distributions
 +
List of officially supported distributions can be found below.
 +
Templates for the following distributions are available through our
 +
repositories. You can use pveam tool or the
 +
Graphical User Interface to download them.
 +
Alpine Linux
 +
Alpine Linux is a security-oriented, lightweight Linux distribution based on
 +
musl libc and busybox.
 +
&#8212; https://alpinelinux.org
 +
For currently supported releases see:
 +
https://alpinelinux.org/releases/
 +
Arch Linux
 +
Arch Linux, a lightweight and flexible Linux® distribution that tries to Keep It Simple.
 +
&#8212; https://archlinux.org/
 +
Arch Linux is using a rolling-release model, see its wiki for more details:
 +
https://wiki.archlinux.org/title/Arch_Linux
 +
CentOS, Almalinux, Rocky Linux
 +
CentOS / CentOS Stream
 +
The CentOS Linux distribution is a stable, predictable, manageable and
 +
reproducible platform derived from the sources of Red Hat Enterprise Linux
 +
(RHEL)
 +
&#8212; https://centos.org
 +
For currently supported releases see:
 +
https://wiki.centos.org/About/Product
 +
Almalinux
 +
An Open Source, community owned and governed, forever-free enterprise Linux
 +
distribution, focused on long-term stability, providing a robust
 +
production-grade platform. AlmaLinux OS is 1:1 binary compatible with RHEL® and
 +
pre-Stream CentOS.
 +
&#8212; https://almalinux.org
 +
For currently supported releases see:
 +
https://en.wikipedia.org/wiki/AlmaLinux#Releases
 +
Rocky Linux
 +
Rocky Linux is a community enterprise operating system designed to be 100%
 +
bug-for-bug compatible with America&#8217;s top enterprise Linux distribution now
 +
that its downstream partner has shifted direction.
 +
&#8212; https://rockylinux.org
 +
For currently supported releases see:
 +
https://en.wikipedia.org/wiki/Rocky_Linux#Releases
 +
Debian
 +
Debian is a free operating system, developed and maintained by the Debian
 +
project. A free Linux distribution with thousands of applications to meet our
 +
users' needs.
 +
&#8212; https://www.debian.org/intro/index#software
 +
For currently supported releases see:
 +
https://www.debian.org/releases/stable/releasenotes
 +
Devuan
 +
Devuan GNU+Linux is a fork of Debian without systemd that allows users to
 +
reclaim control over their system by avoiding unnecessary entanglements and
 +
ensuring Init Freedom.
 +
&#8212; https://www.devuan.org
 +
For currently supported releases see:
 +
https://www.devuan.org/os/releases
 +
Fedora
 +
Fedora creates an innovative, free, and open source platform for hardware,
 +
clouds, and containers that enables software developers and community members
 +
to build tailored solutions for their users.
 +
&#8212; https://getfedora.org
 +
For currently supported releases see:
 +
https://fedoraproject.org/wiki/Releases
 +
Gentoo
 +
a highly flexible, source-based Linux distribution.
 +
&#8212; https://www.gentoo.org
 +
Gentoo is using a rolling-release model.
 +
OpenSUSE
 +
The makers' choice for sysadmins, developers and desktop users.
 +
&#8212; https://www.opensuse.org
 +
For currently supported releases see:
 +
https://get.opensuse.org/leap/
 +
Ubuntu
 +
Ubuntu is the modern, open source operating system on Linux for the enterprise
 +
server, desktop, cloud, and IoT.
 +
&#8212; https://ubuntu.com/
 +
For currently supported releases see:
 +
https://wiki.ubuntu.com/Releases
 +
Container Images
 +
Container images, sometimes also referred to as &#8220;templates&#8221; or
 +
&#8220;appliances&#8221;, are tar archives which contain everything to run a container.
 +
Proxmox VE itself provides a variety of basic templates for the
 +
most common Linux distributions.  They can be
 +
downloaded using the GUI or the pveam (short for Proxmox VE Appliance Manager)
 +
command line utility.  Additionally, TurnKey
 +
Linux container templates are also available to download.
 +
The list of available templates is updated daily through the pve-daily-update
 +
timer. You can also trigger an update manually by executing:
 +
# pveam update
 +
To view the list of available images run:
 +
# 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          alpine-3.12-default_20200823_amd64.tar.xz
 +
system          alpine-3.13-default_20210419_amd64.tar.xz
 +
system          alpine-3.14-default_20210623_amd64.tar.xz
 +
system          archlinux-base_20210420-1_amd64.tar.gz
 +
system          centos-7-default_20190926_amd64.tar.xz
 +
system          centos-8-default_20201210_amd64.tar.xz
 +
system          debian-9.0-standard_9.7-1_amd64.tar.gz
 +
system          debian-10-standard_10.7-1_amd64.tar.gz
 +
system          devuan-3.0-standard_3.0_amd64.tar.gz
 +
system          fedora-33-default_20201115_amd64.tar.xz
 +
system          fedora-34-default_20210427_amd64.tar.xz
 +
system          gentoo-current-default_20200310_amd64.tar.xz
 +
system          opensuse-15.2-default_20200824_amd64.tar.xz
 +
system          ubuntu-16.04-standard_16.04.5-1_amd64.tar.gz
 +
system          ubuntu-18.04-standard_18.04.1-1_amd64.tar.gz
 +
system          ubuntu-20.04-standard_20.04-1_amd64.tar.gz
 +
system          ubuntu-20.10-standard_20.10-1_amd64.tar.gz
 +
system          ubuntu-21.04-standard_21.04-1_amd64.tar.gz
 +
Before you can use such a template, you need to download them into one of your
 +
storages. If you&#8217;re unsure to which one, you can simply use the local named
 +
storage 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-10.0-standard_10.0-1_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-10.0-standard_10.0-1_amd64.tar.gz  219.95MB
 +
You can also use the Proxmox VE web interface GUI to download, list and delete
 +
container templates.
 +
pct uses them to create a new container, for example:
 +
# pct create 999 local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz
 +
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-10.0-standard_10.0-1_amd64.tar.gz
 +
Container Settings
 +
General Settings
 +
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.
 +
Unprivileged Containers
 +
Unprivileged 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, etc.) in these containers will affect a random unprivileged user, and
 +
would be a generic kernel security bug rather than an LXC issue. The LXC team
 +
thinks unprivileged containers are safe by design.
 +
This is the default option when creating a new container.
 +
If the container uses systemd as an init system, please be aware the
 +
systemd version running inside the container should be equal to or greater than
 +
220.
 +
Privileged Containers
 +
Security in containers is achieved by using mandatory access control AppArmor
 +
restrictions, seccomp filters and Linux kernel 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.
 +
That&#8217;s why privileged containers should only be used in trusted environments.
 +
CPU
 +
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 periodically.
 +
To view the assigned CPUs run the following command:
 +
# pct cpusets
 +
---------------------
 +
102:              6 7
 +
105:      2 3 4 5
 +
108:  0 1
 +
---------------------
 +
Containers use the host kernel directly. All tasks 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.
 +
Memory
 +
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).
 +
Mount Points
 +
The root mount point is configured with the rootfs property. You can
 +
configure up to 256 additional mount points. The corresponding options are
 +
called mp0 to mp255. They can contain the following settings:
 +
rootfs: [volume=]&lt;volume&gt; [,acl=&lt;1|0&gt;] [,mountoptions=&lt;opt[;opt...]&gt;] [,quota=&lt;1|0&gt;] [,replicate=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,shared=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
 +
Use volume as container root. See below for a detailed description of all options.
 +
mp[n]: [volume=]&lt;volume&gt; ,mp=&lt;Path&gt; [,acl=&lt;1|0&gt;] [,backup=&lt;1|0&gt;] [,mountoptions=&lt;opt[;opt...]&gt;] [,quota=&lt;1|0&gt;] [,replicate=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,shared=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
 +
Use volume as container mount point. Use the special syntax STORAGE_ID:SIZE_IN_GiB to allocate a new volume.
 +
acl=&lt;boolean&gt;
 +
Explicitly enable or disable ACL support.
 +
backup=&lt;boolean&gt;
 +
Whether to include the mount point in backups (only used for volume mount points).
 +
mountoptions=&lt;opt[;opt...]&gt;
 +
Extra mount options for rootfs/mps.
 +
mp=&lt;Path&gt;
 +
Path to the mount point as seen from inside the container.
 +
Must not contain any symlinks for security reasons.
 +
quota=&lt;boolean&gt;
 +
Enable user quotas inside the container (not supported with zfs subvolumes)
 +
replicate=&lt;boolean&gt; (default = 1)
 +
Will include this volume to a storage replica job.
 +
ro=&lt;boolean&gt;
 +
Read-only mount point
 +
shared=&lt;boolean&gt; (default = 0)
 +
Mark this non-volume mount point as available on all nodes.
 +
This option does not share the mount point automatically, it assumes it is shared already!
 +
size=&lt;DiskSize&gt;
 +
Volume size (read only value).
 +
volume=&lt;volume&gt;
 +
Volume, device or directory to mount into the container.
 +
Currently there are 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.
 +
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. For example, 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, and setup the moutpoint in the
 +
container at /path/in/container
 +
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.
 +
The contents of bind mount points are not backed up when using vzdump.
 +
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.
 +
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&#8217;s
 +
storage subsystem, but the quota and acl options will be honored.
 +
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.
 +
The contents of device mount points are not backed up when using
 +
vzdump.
 +
Network
 +
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=&lt;string&gt; [,bridge=&lt;bridge&gt;] [,firewall=&lt;1|0&gt;] [,gw=&lt;GatewayIPv4&gt;] [,gw6=&lt;GatewayIPv6&gt;] [,hwaddr=&lt;XX:XX:XX:XX:XX:XX&gt;] [,ip=&lt;(IPv4/CIDR|dhcp|manual)&gt;] [,ip6=&lt;(IPv6/CIDR|auto|dhcp|manual)&gt;] [,mtu=&lt;integer&gt;] [,rate=&lt;mbps&gt;] [,tag=&lt;integer&gt;] [,trunks=&lt;vlanid[;vlanid...]&gt;] [,type=&lt;veth&gt;]
 +
Specifies network interfaces for the container.
 +
bridge=&lt;bridge&gt;
 +
Bridge to attach the network device to.
 +
firewall=&lt;boolean&gt;
 +
Controls whether this interface&#8217;s firewall rules should be used.
 +
gw=&lt;GatewayIPv4&gt;
 +
Default gateway for IPv4 traffic.
 +
gw6=&lt;GatewayIPv6&gt;
 +
Default gateway for IPv6 traffic.
 +
hwaddr=&lt;XX:XX:XX:XX:XX:XX&gt;
 +
A common MAC address with the I/G (Individual/Group) bit not set.
 +
ip=&lt;(IPv4/CIDR|dhcp|manual)&gt;
 +
IPv4 address in CIDR format.
 +
ip6=&lt;(IPv6/CIDR|auto|dhcp|manual)&gt;
 +
IPv6 address in CIDR format.
 +
mtu=&lt;integer&gt; (64 - N)
 +
Maximum transfer unit of the interface. (lxc.network.mtu)
 +
name=&lt;string&gt;
 +
Name of the network device as seen from inside the container. (lxc.network.name)
 +
rate=&lt;mbps&gt;
 +
Apply rate limiting to the interface
 +
tag=&lt;integer&gt; (1 - 4094)
 +
VLAN tag for this interface.
 +
trunks=&lt;vlanid[;vlanid...]&gt;
 +
VLAN ids to pass through the interface
 +
type=&lt;veth&gt;
 +
Network interface type.
 +
Automatic Start and Shutdown of Containers
 +
To automatically start a container when the host system boots, select the
 +
option Start at boot in the Options panel of the container in the web
 +
interface or run the following command:
 +
# pct set CTID -onboot 1
 +
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. For example, 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. For example, 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.
 +
If you require a delay between the host boot and the booting of the first
 +
container, see the section on
 +
Proxmox VE Node Management.
 +
Hookscripts
 +
You can add a hook script to CTs with the config property hookscript.
 +
# pct set 100 -hookscript local:snippets/hookscript.pl
 +
It will be called during various phases of the guests lifetime.  For an example
 +
and documentation see the example script under
 +
/usr/share/pve-docs/examples/guest-example-hookscript.pl.
 
Security Considerations
 
Security Considerations
−
Containers use the same kernel as the host, so there is a big attack
+
Containers use the kernel of the host system. This exposes an attack surface
−
surface for malicious users. You should consider this fact if you
+
for malicious users. In general, full virtual machines provide better
−
provide containers to totally untrusted people. In general, fully
+
isolation. This should be considered if containers are provided to unknown or
−
virtualized VMs provide better isolation.
+
untrusted people.
−
The good news is that LXC uses many kernel security features like
+
To reduce the attack surface, LXC uses many security features like AppArmor,
−
AppArmor, CGroups and PID and user namespaces, which makes containers
+
CGroups and kernel namespaces.
−
usage quite secure. We distinguish two types of containers:
+
AppArmor
−
Privileged Containers
+
AppArmor profiles are used to restrict access to possibly dangerous actions.
−
Security is done by dropping capabilities, using mandatory access
+
Some system calls, i.e. mount, are prohibited from execution.
−
control (AppArmor), SecComp filters and namespaces. The LXC team
+
To trace AppArmor activity, use:
−
considers this kind of container as unsafe, and they will not consider
+
# dmesg | grep apparmor
−
new container escape exploits to be security issues worthy of a CVE
+
Although it is not recommended, AppArmor can be disabled for a container. This
−
and quick fix. So you should use this kind of containers only inside a
+
brings security risks with it. Some syscalls can lead to privilege escalation
−
trusted environment, or when no untrusted task is running as root in
+
when executed within a container if the system is misconfigured or if a LXC or
−
the container.
+
Linux Kernel vulnerability exists.
−
Unprivileged Containers
+
To disable AppArmor for a container, add the following line to the container
−
This kind of containers use a new kernel feature called user
+
configuration file located at /etc/pve/lxc/CTID.conf:
−
namespaces. The root UID 0 inside the container is mapped to an
+
lxc.apparmor.profile = unconfined
−
unprivileged user outside the container. This means that most security
+
Please note that this is not recommended for production use.
−
issues (container escape, resource abuse, &#8230;) in those containers
+
Control Groups (cgroup)
−
will affect a random unprivileged user, and so would be a generic
+
cgroup is a kernel
−
kernel security bug rather than an LXC issue. The LXC team thinks
+
mechanism used to hierarchically organize processes and distribute system
−
unprivileged containers are safe by design.
+
resources.
−
Configuration
+
The main resources controlled via cgroups are CPU time, memory and swap
−
The /etc/pve/lxc/&lt;CTID&gt;.conf file stores container configuration,
+
limits, and access to device nodes. cgroups are also used to "freeze" a
−
where &lt;CTID&gt; is the numeric ID of the given container. Like all
+
container before taking snapshots.
−
other files stored inside /etc/pve/, they get automatically
+
There are 2 versions of cgroups currently available,
−
replicated to all other cluster nodes.
+
legacy
−
CTIDs &lt; 100 are reserved for internal purposes, and CTIDs need to be
+
and
−
unique cluster wide.
+
cgroupv2.
−
Example Container Configuration
+
Since Proxmox VE 7.0, the default is a pure cgroupv2 environment. Previously a
−
ostype: debian
+
"hybrid" setup was used, where resource control was mainly done in cgroupv1
−
arch: amd64
+
with an additional cgroupv2 controller which could take over some subsystems
−
hostname: www
+
via the cgroup_no_v1 kernel command line parameter. (See the
−
memory: 512
+
kernel
−
swap: 512
+
parameter documentation for details.)
−
net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
+
CGroup Version Compatibility
−
rootfs: local:107/vm-107-disk-1.raw,size=7G
+
The main difference between pure cgroupv2 and the old hybrid environments
−
Those configuration files are simple text files, and you can edit them
+
regarding Proxmox VE is that with cgroupv2 memory and swap are now controlled
−
using a normal text editor (vi, nano, &#8230;). This is sometimes
+
independently. The memory and swap settings for containers can map directly to
−
useful to do small corrections, but keep in mind that you need to
+
these values, whereas previously only the memory limit and the limit of the
−
restart the container to apply such changes.
+
sum of memory and swap could be limited.
−
For that reason, it is usually better to use the pct command to
+
Another important difference is that the devices controller is configured in a
−
generate and modify those files, or do the whole thing using the GUI.
+
completely different way. Because of this, file system quotas are currently not
−
Our toolkit is smart enough to instantaneously apply most changes to
+
supported in a pure cgroupv2 environment.
−
running containers. This feature is called "hot plug", and there is no
+
cgroupv2 support by the container&#8217;s OS is needed to run in a pure cgroupv2
−
need to restart the container in that case.
+
environment. Containers running systemd version 231 or newer support
−
File Format
+
cgroupv2 [this includes all newest major versions of container
−
Container configuration files use a simple colon separated key/value
+
templates shipped by Proxmox VE], as do containers not using systemd as init
−
format. Each line has the following format:
+
system [for example Alpine Linux].
−
# this is a comment
+
CentOS 7 and Ubuntu 16.10 are two prominent Linux distributions releases,
−
OPTION: value
+
which have a systemd version that is too old to run in a cgroupv2
−
Blank lines in those files are ignored, and lines starting with a #
+
environment, you can either
−
character are treated as comments and are also ignored.
+
Upgrade the whole distribution to a newer release. For the examples above, that
−
It is possible to add low-level, LXC style configuration directly, for
+
  could be Ubuntu 18.04 or 20.04, and CentOS 8 (or RHEL/CentOS derivatives like
−
example:
+
  AlmaLinux or Rocky Linux). This has the benefit to get the newest bug and
−
lxc.init_cmd: /sbin/my_own_init
+
  security fixes, often also new features, and moving the EOL date in the future.
−
or
+
Upgrade the Containers systemd version. If the distribution provides a
−
lxc.init_cmd = /sbin/my_own_init
+
  backports repository this can be an easy and quick stop-gap measurement.
−
Those settings are directly passed to the LXC low-level tools.
+
Move the container, or its services, to a Virtual Machine. Virtual Machines
−
Snapshots
+
  have a much less interaction with the host, that&#8217;s why one can install
−
When you create a snapshot, pct stores the configuration at snapshot
+
  decades old OS versions just fine there.
−
time into a separate snapshot section within the same configuration
+
Switch back to the legacy cgroup controller. Note that while it can be a
−
file. For example, after creating a snapshot called &#8220;testsnapshot&#8221;,
+
  valid solution, it&#8217;s not a permanent one. There&#8217;s a high likelihood that a
−
your configuration file will look like this:
+
  future Proxmox VE major release, for example 8.0, cannot support the legacy
−
Container configuration with snapshot
+
  controller anymore.
−
memory: 512
+
Changing CGroup Version
−
swap: 512
+
If file system quotas are not required and all containers support cgroupv2,
−
parent: testsnaphot
+
it is recommended to stick to the new default.
−
...
+
To switch back to the previous version the following kernel command line
−
[testsnaphot]
+
parameter can be used:
−
memory: 512
+
systemd.unified_cgroup_hierarchy=0
−
swap: 512
+
See this section on editing the kernel boot
−
snaptime: 1457170803
+
command line on where to add the parameter.
−
...
 
−
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).
 
 
Guest Operating System Configuration
 
Guest Operating System Configuration
−
We normally try to detect the operating system type inside the
+
Proxmox VE tries to detect the Linux distribution in the container, and modifies
−
container, and then modify some files inside the container to make
+
some files. Here is a short list of things done at container startup:
−
them work as expected. Here is a short list of things we do at
 
−
container startup:
 
 
set /etc/hostname
 
set /etc/hostname
 
to set the container name
 
to set the container name
Line 138: Line 481:
 
&lt;data&gt;
 
&lt;data&gt;
 
# --- END PVE ---
 
# --- END PVE ---
−
Those markers will be inserted at a reasonable location in the
+
Those markers will be inserted at a reasonable location in the file. If such a
−
file. If such a section already exists, it will be updated in place
+
section already exists, it will be updated in place and will not be moved.
−
and will not be moved.
+
Modification of a file can be prevented by adding a .pve-ignore. file for it.
−
Modification of a file can be prevented by adding a .pve-ignore.
+
For instance, if the file /etc/.pve-ignore.hosts exists then the /etc/hosts
−
file for it. For instance, if the file /etc/.pve-ignore.hosts
+
file will not be touched. This can be a simple empty file created via:
−
exists then the /etc/hosts file will not be touched. This can be a
 
−
simple empty file creatd via:
 
 
# touch /etc/.pve-ignore.hosts
 
# touch /etc/.pve-ignore.hosts
 
Most modifications are OS dependent, so they differ between different
 
Most modifications are OS dependent, so they differ between different
−
distributions and versions. You can completely disable modifications
+
distributions and versions. You can completely disable modifications by
−
by manually setting the ostype to unmanaged.
+
manually setting the ostype to unmanaged.
 
OS type detection is done by testing for certain files inside the
 
OS type detection is done by testing for certain files inside the
−
container:
+
container. Proxmox VE first checks the /etc/os-release file
 +
[/etc/os-release replaces the multitude of per-distribution
 +
release files https://manpages.debian.org/stable/systemd/os-release.5.en.html].
 +
If that file is not present, or it does not contain a clearly recognizable
 +
distribution identifier the following distribution specific release files are
 +
checked.
 
Ubuntu
 
Ubuntu
 
inspect /etc/lsb-release (DISTRIB_ID=Ubuntu)
 
inspect /etc/lsb-release (DISTRIB_ID=Ubuntu)
Line 167: Line 513:
 
Container start fails if the configured ostype differs from the auto
 
Container start fails if the configured ostype differs from the auto
 
detected type.
 
detected type.
 +
Container Storage
 +
The Proxmox VE LXC container storage model is more flexible than traditional
 +
container storage models. A container can have multiple mount points. This
 +
makes it possible to use the best suited storage for each application.
 +
For example the root file system of the container can be on slow and cheap
 +
storage while the database can be on fast and distributed storage via a second
 +
mount point. See section  Mount Points for further
 +
details.
 +
Any storage type supported by the Proxmox VE storage library can be used. This means
 +
that containers can be stored on local (for example lvm, zfs or directory),
 +
shared external (like iSCSI, NFS) or even distributed storage systems like
 +
Ceph. Advanced storage features like snapshots or clones can be used if the
 +
underlying storage supports them. The vzdump backup tool can use snapshots to
 +
provide consistent container backups.
 +
Furthermore, local devices or local directories can be mounted directly using
 +
bind mounts. This gives access to local resources inside a container with
 +
practically zero overhead. Bind mounts can be used as an easy way to share data
 +
between containers.
 +
FUSE Mounts
 +
Because of existing issues in the Linux kernel&#8217;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.
 +
Using Quotas Inside Containers
 +
Quotas allow to set limits inside a container for the amount of disk space that
 +
each user can use.
 +
This currently requires the use of legacy cgroups.
 +
This only works on ext4 image based storage types and currently only
 +
works with privileged 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 on any other system. You can initialize the
 +
/aquota.user and /aquota.group files by running:
 +
# quotacheck -cmug /
 +
# quotaon /
 +
Then edit the quotas using the edquota command. Refer to the documentation of
 +
the distribution running inside the container for details.
 +
You need to run the above commands for every mount point by passing the
 +
mount point&#8217;s path instead of just /.
 +
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.
 +
Backup of Container mount points
 +
To include a mount point in backups, enable the backup option for it in the
 +
container configuration. For an existing mount point mp0
 +
mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G
 +
add backup=1 to enable it.
 +
mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G,backup=1
 +
When creating a new mount point in the GUI, this option is enabled by
 +
default.
 +
To disable backups for a mount point, add backup=0 in the way described
 +
above, or uncheck the Backup checkbox on the GUI.
 +
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, you can set the Skip replication option for that mount point.
 +
As of Proxmox VE 5.0, replication requires a storage of type zfspool. Adding a
 +
mount point to a different type of storage when the container has replication
 +
configured requires to have Skip replication enabled for that mount point.
 +
Backup and Restore
 +
Container Backup
 +
It is possible to use the vzdump tool for container backup. Please refer to
 +
the vzdump manual page for details.
 +
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).
 +
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:
 +
&#8220;Simple&#8221; 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:
 +
Extract mount points and their options from backup
 +
Create volumes for storage backed mount points on the storage provided with
 +
  the storage parameter (default: local).
 +
Extract files from backup archive
 +
Add bind and device mount points to restored configuration (limited to root
 +
  user)
 +
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.
 +
&#8220;Advanced&#8221; 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)
 +
Managing Containers with pct
 +
The &#8220;Proxmox Container Toolkit&#8221; (pct) is the command line tool to manage
 +
Proxmox VE containers. It enables you to create or destroy containers, as well as
 +
control the container execution (start, stop, reboot, migrate, etc.). It can be
 +
used to set parameters in the config file of a container, for example the
 +
network configuration or memory limits.
 +
CLI Usage Examples
 +
Create a container based on a Debian template (provided you have already
 +
downloaded the template via the web interface)
 +
# pct create 100 /var/lib/vz/template/cache/debian-10.0-standard_10.0-1_amd64.tar.gz
 +
Start container 100
 +
# pct start 100
 +
Start a login session via getty
 +
# pct console 100
 +
Enter the LXC namespace and run a shell as root user
 +
# pct enter 100
 +
Display the configuration
 +
# pct config 100
 +
Add a network interface called eth0, bridged to the host bridge vmbr0, set
 +
the address and gateway, while it&#8217;s running
 +
# pct set 100 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.147/24,gw=192.168.15.1
 +
Reduce the memory of the container to 512MB
 +
# pct set 100 -memory 512
 +
Destroying a container always removes it from Access Control Lists and it always
 +
removes the firewall configuration of the container. You have to activate
 +
--purge, if you want to additionally remove the container from replication jobs,
 +
backup jobs and HA resource configurations.
 +
# pct destroy 100 --purge
 +
Move a mount point volume to a different storage.
 +
# pct move-volume 100 mp0 other-storage
 +
Reassign a volume to a different CT. This will remove the volume mp0 from
 +
the source CT and attaches it as mp1 to the target CT. In the background
 +
the volume is being renamed so that the name matches the new owner.
 +
#  pct move-volume 100 mp0 --target-vmid 200 --target-volume mp1
 +
Obtaining Debugging Logs
 +
In case pct start is unable to start a specific container, it might be
 +
helpful to collect debugging output by passing the --debug flag (replace CTID with
 +
the container&#8217;s CTID):
 +
# pct start CTID --debug
 +
Alternatively, you can use the following lxc-start command, which will save
 +
the debug log to the file specified by the -o output option:
 +
# lxc-start -n CTID -F -l DEBUG -o /tmp/lxc-CTID.log
 +
This command will attempt to start the container in foreground mode, to stop
 +
the container run pct shutdown CTID or pct stop CTID in a second terminal.
 +
The collected debug log is written to /tmp/lxc-CTID.log.
 +
If you have changed the container&#8217;s configuration since the last start
 +
attempt with pct start, you need to run pct start at least once to also
 +
update the configuration used by lxc-start.
 +
Migration
 +
If you have a cluster, you can migrate your Containers with
 +
# pct migrate &lt;ctid&gt; &lt;target&gt;
 +
This works as long as your Container is offline. If it has local volumes or
 +
mount points defined, the migration will copy the content over the network to
 +
the target host if the same storage is defined there.
 +
Running containers cannot live-migrated due to technical limitations. You can
 +
do a restart migration, which shuts down, moves and then starts a container
 +
again on the target node. As containers are very lightweight, this results
 +
normally only in a downtime of some hundreds of milliseconds.
 +
A restart migration can be done through the web interface or by using the
 +
--restart flag with the pct migrate command.
 +
A restart migration will shut down the Container and kill it after the
 +
specified timeout (the default is 180 seconds). Then it will migrate the
 +
Container like an offline migration and when finished, it starts the Container
 +
on the target node.
 +
Configuration
 +
The /etc/pve/lxc/&lt;CTID&gt;.conf file stores container configuration, where
 +
&lt;CTID&gt; is the numeric ID of the given container. Like all other files stored
 +
inside /etc/pve/, they get automatically replicated to all other cluster
 +
nodes.
 +
CTIDs &lt; 100 are reserved for internal purposes, and CTIDs need to be
 +
unique cluster wide.
 +
Example Container Configuration
 +
ostype: debian
 +
arch: amd64
 +
hostname: www
 +
memory: 512
 +
swap: 512
 +
net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
 +
rootfs: local:107/vm-107-disk-1.raw,size=7G
 +
The configuration files are simple text files. You can edit them using a normal
 +
text editor, for example, vi or nano.
 +
This is sometimes useful to do small corrections, but keep in mind that you
 +
need to restart the container to apply such changes.
 +
For that reason, it is usually better to use the pct 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
 +
containers. This feature is called &#8220;hot plug&#8221;, and there is no need to restart
 +
the container in that case.
 +
In cases where a change cannot be hot-plugged, it will be registered as a
 +
pending change (shown in red color in the GUI).
 +
They will only be applied after rebooting the container.
 +
File Format
 +
The container configuration file uses 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.
 +
It is possible to add low-level, LXC style configuration directly, for example:
 +
lxc.init_cmd: /sbin/my_own_init
 +
or
 +
lxc.init_cmd = /sbin/my_own_init
 +
The settings are passed directly to the LXC low-level tools.
 +
Snapshots
 +
When you create a snapshot, pct stores the configuration at snapshot time
 +
into a separate snapshot section within the same configuration file. For
 +
example, after creating a snapshot called &#8220;testsnapshot&#8221;, your configuration
 +
file will look like this:
 +
Container 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).
 
Options
 
Options
−
arch: (amd64 | i386) (default=amd64)
+
arch: &lt;amd64 | arm64 | armhf | i386&gt; (default = amd64)
 
OS architecture type.
 
OS architecture type.
−
cmode: (console | shell | tty) (default=tty)
+
cmode: &lt;console | shell | tty&gt; (default = tty)
 
Console mode. By default, the console command tries to open a connection to one of the available tty devices. By setting cmode to console it tries to attach to /dev/console instead. If you set cmode to shell, it simply invokes a shell inside the container (no login).
 
Console mode. By default, the console command tries to open a connection to one of the available tty devices. By setting cmode to console it tries to attach to /dev/console instead. If you set cmode to shell, it simply invokes a shell inside the container (no login).
−
console: boolean (default=1)
+
console: &lt;boolean&gt; (default = 1)
 
Attach a console device (/dev/console) to the container.
 
Attach a console device (/dev/console) to the container.
−
cpulimit: number (0 - 128) (default=0)
+
cores: &lt;integer&gt; (1 - 8192)
 +
The number of cores assigned to the container. A container can use all available cores by default.
 +
cpulimit: &lt;number&gt; (0 - 8192) (default = 0)
 
Limit of CPU usage.
 
Limit of CPU usage.
 
If the computer has 2 CPUs, it has a total of 2 CPU time. Value 0 indicates no CPU limit.
 
If the computer has 2 CPUs, it has a total of 2 CPU time. Value 0 indicates no CPU limit.
−
cpuunits: integer (0 - 500000) (default=1024)
+
cpuunits: &lt;integer&gt; (0 - 500000) (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 the weights of all the other running VMs.
 
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 the weights of all the other running VMs.
 
You can disable fair-scheduler configuration by setting this to 0.
 
You can disable fair-scheduler configuration by setting this to 0.
−
description: string
+
debug: &lt;boolean&gt; (default = 0)
−
Container description. Only used on the configuration web interface.
+
Try to be more verbose. For now this only enables debug log-level on start.
−
hostname: string
+
description: &lt;string&gt;
 +
Description for the Container. Shown in the web-interface CT&#8217;s summary. This is saved as comment inside the configuration file.
 +
features: [force_rw_sys=&lt;1|0&gt;] [,fuse=&lt;1|0&gt;] [,keyctl=&lt;1|0&gt;] [,mknod=&lt;1|0&gt;] [,mount=&lt;fstype;fstype;...&gt;] [,nesting=&lt;1|0&gt;]
 +
Allow containers access to advanced features.
 +
force_rw_sys=&lt;boolean&gt; (default = 0)
 +
Mount /sys in unprivileged containers as rw instead of mixed. This can break networking under newer (&gt;= v245) systemd-network use.
 +
fuse=&lt;boolean&gt; (default = 0)
 +
Allow using fuse file systems in a container. Note that interactions between fuse and the freezer cgroup can potentially cause I/O deadlocks.
 +
keyctl=&lt;boolean&gt; (default = 0)
 +
For unprivileged containers only: Allow the use of the keyctl() system call. This is required to use docker inside a container. By default unprivileged containers will see this system call as non-existent. This is mostly a workaround for systemd-networkd, as it will treat it as a fatal error when some keyctl() operations are denied by the kernel due to lacking permissions. Essentially, you can choose between running systemd-networkd or docker.
 +
mknod=&lt;boolean&gt; (default = 0)
 +
Allow unprivileged containers to use mknod() to add certain device nodes. This requires a kernel with seccomp trap to user space support (5.3 or newer). This is experimental.
 +
mount=&lt;fstype;fstype;...&gt;
 +
Allow mounting file systems of specific types. This should be a list of file system types as used with the mount command. Note that this can have negative effects on the container&#8217;s security. With access to a loop device, mounting a file can circumvent the mknod permission of the devices cgroup, mounting an NFS file system can block the host&#8217;s I/O completely and prevent it from rebooting, etc.
 +
nesting=&lt;boolean&gt; (default = 0)
 +
Allow nesting. Best used with unprivileged containers with additional id mapping. Note that this will expose procfs and sysfs contents of the host to the guest.
 +
hookscript: &lt;string&gt;
 +
Script that will be exectued during various steps in the containers lifetime.
 +
hostname: &lt;string&gt;
 
Set a host name for the container.
 
Set a host name for the container.
−
lock: (backup | migrate | rollback | snapshot)
+
lock: &lt;backup | create | destroyed | disk | fstrim | migrate | mounted | rollback | snapshot | snapshot-delete&gt;
 
Lock/unlock the VM.
 
Lock/unlock the VM.
−
memory: integer (16 - N) (default=512)
+
memory: &lt;integer&gt; (16 - N) (default = 512)
 
Amount of RAM for the VM in MB.
 
Amount of RAM for the VM in MB.
−
mp[n]: [volume=]&lt;volume&gt; ,mp=&lt;Path&gt; [,acl=&lt;1|0&gt;] [,backup=&lt;1|0&gt;] [,quota=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
+
mp[n]: [volume=]&lt;volume&gt; ,mp=&lt;Path&gt; [,acl=&lt;1|0&gt;] [,backup=&lt;1|0&gt;] [,mountoptions=&lt;opt[;opt...]&gt;] [,quota=&lt;1|0&gt;] [,replicate=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,shared=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
−
Use volume as container mount point.
+
Use volume as container mount point. Use the special syntax STORAGE_ID:SIZE_IN_GiB to allocate a new volume.
−
acl=boolean
+
acl=&lt;boolean&gt;
 
Explicitly enable or disable ACL support.
 
Explicitly enable or disable ACL support.
−
backup=boolean
+
backup=&lt;boolean&gt;
−
Whether to include the mountpoint in backups (only used for volume mountpoints).
+
Whether to include the mount point in backups (only used for volume mount points).
 +
mountoptions=&lt;opt[;opt...]&gt;
 +
Extra mount options for rootfs/mps.
 
mp=&lt;Path&gt;
 
mp=&lt;Path&gt;
−
Path to the mountpoint as seen from inside the container.
+
Path to the mount point as seen from inside the container.
 
Must not contain any symlinks for security reasons.
 
Must not contain any symlinks for security reasons.
−
quota=boolean
+
quota=&lt;boolean&gt;
 
Enable user quotas inside the container (not supported with zfs subvolumes)
 
Enable user quotas inside the container (not supported with zfs subvolumes)
−
ro=boolean
+
replicate=&lt;boolean&gt; (default = 1)
−
Read-only mountpoint
+
Will include this volume to a storage replica job.
 +
ro=&lt;boolean&gt;
 +
Read-only mount point
 +
shared=&lt;boolean&gt; (default = 0)
 +
Mark this non-volume mount point as available on all nodes.
 +
This option does not share the mount point automatically, it assumes it is shared already!
 
size=&lt;DiskSize&gt;
 
size=&lt;DiskSize&gt;
 
Volume size (read only value).
 
Volume size (read only value).
 
volume=&lt;volume&gt;
 
volume=&lt;volume&gt;
 
Volume, device or directory to mount into the container.
 
Volume, device or directory to mount into the container.
−
nameserver: string
+
nameserver: &lt;string&gt;
 
Sets DNS server IP address for a container. Create will automatically use the setting from the host if you neither set searchdomain nor nameserver.
 
Sets DNS server IP address for a container. Create will automatically use the setting from the host if you neither set searchdomain nor nameserver.
−
net[n]: name=&lt;string&gt; [,bridge=&lt;bridge&gt;] [,firewall=&lt;1|0&gt;] [,gw=&lt;GatewayIPv4&gt;] [,gw6=&lt;GatewayIPv6&gt;] [,hwaddr=&lt;XX:XX:XX:XX:XX:XX&gt;] [,ip=&lt;IPv4Format/CIDR&gt;] [,ip6=&lt;IPv6Format/CIDR&gt;] [,mtu=&lt;integer&gt;] [,rate=&lt;mbps&gt;] [,tag=&lt;integer&gt;] [,trunks=&lt;vlanid[;vlanid...]&gt;] [,type=&lt;veth&gt;]
+
net[n]: name=&lt;string&gt; [,bridge=&lt;bridge&gt;] [,firewall=&lt;1|0&gt;] [,gw=&lt;GatewayIPv4&gt;] [,gw6=&lt;GatewayIPv6&gt;] [,hwaddr=&lt;XX:XX:XX:XX:XX:XX&gt;] [,ip=&lt;(IPv4/CIDR|dhcp|manual)&gt;] [,ip6=&lt;(IPv6/CIDR|auto|dhcp|manual)&gt;] [,mtu=&lt;integer&gt;] [,rate=&lt;mbps&gt;] [,tag=&lt;integer&gt;] [,trunks=&lt;vlanid[;vlanid...]&gt;] [,type=&lt;veth&gt;]
 
Specifies network interfaces for the container.
 
Specifies network interfaces for the container.
 
bridge=&lt;bridge&gt;
 
bridge=&lt;bridge&gt;
 
Bridge to attach the network device to.
 
Bridge to attach the network device to.
−
firewall=boolean
+
firewall=&lt;boolean&gt;
 
Controls whether this interface&#8217;s firewall rules should be used.
 
Controls whether this interface&#8217;s firewall rules should be used.
 
gw=&lt;GatewayIPv4&gt;
 
gw=&lt;GatewayIPv4&gt;
Line 218: Line 818:
 
Default gateway for IPv6 traffic.
 
Default gateway for IPv6 traffic.
 
hwaddr=&lt;XX:XX:XX:XX:XX:XX&gt;
 
hwaddr=&lt;XX:XX:XX:XX:XX:XX&gt;
−
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)
+
A common MAC address with the I/G (Individual/Group) bit not set.
−
ip=&lt;IPv4Format/CIDR&gt;
+
ip=&lt;(IPv4/CIDR|dhcp|manual)&gt;
 
IPv4 address in CIDR format.
 
IPv4 address in CIDR format.
−
ip6=&lt;IPv6Format/CIDR&gt;
+
ip6=&lt;(IPv6/CIDR|auto|dhcp|manual)&gt;
 
IPv6 address in CIDR format.
 
IPv6 address in CIDR format.
−
mtu=integer (64 - N)
+
mtu=&lt;integer&gt; (64 - N)
 
Maximum transfer unit of the interface. (lxc.network.mtu)
 
Maximum transfer unit of the interface. (lxc.network.mtu)
 
name=&lt;string&gt;
 
name=&lt;string&gt;
Line 229: Line 829:
 
rate=&lt;mbps&gt;
 
rate=&lt;mbps&gt;
 
Apply rate limiting to the interface
 
Apply rate limiting to the interface
−
tag=integer (1 - 4094)
+
tag=&lt;integer&gt; (1 - 4094)
 
VLAN tag for this interface.
 
VLAN tag for this interface.
 
trunks=&lt;vlanid[;vlanid...]&gt;
 
trunks=&lt;vlanid[;vlanid...]&gt;
 
VLAN ids to pass through the interface
 
VLAN ids to pass through the interface
−
type=(veth)
+
type=&lt;veth&gt;
 
Network interface type.
 
Network interface type.
−
onboot: boolean (default=0)
+
onboot: &lt;boolean&gt; (default = 0)
 
Specifies whether a VM will be started during system bootup.
 
Specifies whether a VM will be started during system bootup.
−
ostype: (alpine | archlinux | centos | debian | fedora | gentoo | opensuse | ubuntu | unmanaged)
+
ostype: &lt;alpine | archlinux | centos | debian | devuan | fedora | gentoo | opensuse | ubuntu | unmanaged&gt;
 
OS type. This is used to setup configuration inside the container, and corresponds to lxc setup scripts in /usr/share/lxc/config/&lt;ostype&gt;.common.conf. Value unmanaged can be used to skip and OS specific setup.
 
OS type. This is used to setup configuration inside the container, and corresponds to lxc setup scripts in /usr/share/lxc/config/&lt;ostype&gt;.common.conf. Value unmanaged can be used to skip and OS specific setup.
−
protection: boolean (default=0)
+
protection: &lt;boolean&gt; (default = 0)
 
Sets the protection flag of the container. This will prevent the CT or CT&#8217;s disk remove/update operation.
 
Sets the protection flag of the container. This will prevent the CT or CT&#8217;s disk remove/update operation.
−
rootfs: [volume=]&lt;volume&gt; [,acl=&lt;1|0&gt;] [,quota=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
+
rootfs: [volume=]&lt;volume&gt; [,acl=&lt;1|0&gt;] [,mountoptions=&lt;opt[;opt...]&gt;] [,quota=&lt;1|0&gt;] [,replicate=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,shared=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
 
Use volume as container root.
 
Use volume as container root.
−
acl=boolean
+
acl=&lt;boolean&gt;
 
Explicitly enable or disable ACL support.
 
Explicitly enable or disable ACL support.
−
quota=boolean
+
mountoptions=&lt;opt[;opt...]&gt;
 +
Extra mount options for rootfs/mps.
 +
quota=&lt;boolean&gt;
 
Enable user quotas inside the container (not supported with zfs subvolumes)
 
Enable user quotas inside the container (not supported with zfs subvolumes)
−
ro=boolean
+
replicate=&lt;boolean&gt; (default = 1)
−
Read-only mountpoint
+
Will include this volume to a storage replica job.
 +
ro=&lt;boolean&gt;
 +
Read-only mount point
 +
shared=&lt;boolean&gt; (default = 0)
 +
Mark this non-volume mount point as available on all nodes.
 +
This option does not share the mount point automatically, it assumes it is shared already!
 
size=&lt;DiskSize&gt;
 
size=&lt;DiskSize&gt;
 
Volume size (read only value).
 
Volume size (read only value).
 
volume=&lt;volume&gt;
 
volume=&lt;volume&gt;
 
Volume, device or directory to mount into the container.
 
Volume, device or directory to mount into the container.
−
searchdomain: string
+
searchdomain: &lt;string&gt;
 
Sets DNS search domains for a container. Create will automatically use the setting from the host if you neither set searchdomain nor nameserver.
 
Sets DNS search domains for a container. Create will automatically use the setting from the host if you neither set searchdomain nor nameserver.
 
startup: `[[order=]\d+] [,up=\d+] [,down=\d+] `
 
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.
 
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.
−
swap: integer (0 - N) (default=512)
+
swap: &lt;integer&gt; (0 - N) (default = 512)
 
Amount of SWAP for the VM in MB.
 
Amount of SWAP for the VM in MB.
−
template: boolean (default=0)
+
tags: &lt;string&gt;
 +
Tags of the Container. This is only meta information.
 +
template: &lt;boolean&gt; (default = 0)
 
Enable/disable Template.
 
Enable/disable Template.
−
tty: integer (0 - 6) (default=2)
+
timezone: &lt;string&gt;
 +
Time zone to use in the container. If option isn&#8217;t set, then nothing will be done. Can be set to host to match the host time zone, or an arbitrary time zone option from /usr/share/zoneinfo/zone.tab
 +
tty: &lt;integer&gt; (0 - 6) (default = 2)
 
Specify the number of tty available to the container
 
Specify the number of tty available to the container
−
unprivileged: boolean (default=0)
+
unprivileged: &lt;boolean&gt; (default = 0)
 
Makes the container run as unprivileged user. (Should not be modified manually.)
 
Makes the container run as unprivileged user. (Should not be modified manually.)
−
unused[n]: string
+
unused[n]: [volume=]&lt;volume&gt;
 
Reference to unused volumes. This is used internally, and should not be modified manually.
 
Reference to unused volumes. This is used internally, and should not be modified manually.
−
Container Images
+
volume=&lt;volume&gt;
−
Container images, sometimes also referred to as &#8220;templates&#8221; or
+
The volume that is not used currently.
−
&#8220;appliances&#8221;, are tar archives which contain everything to run a
+
Locks
−
container. You can think of it as a tidy container backup. Like most
+
Container migrations, snapshots and backups (vzdump) set a lock to prevent
−
modern container toolkits, pct uses those images when you create a
+
incompatible concurrent actions on the affected container. Sometimes you need
−
new container, for example:
+
to remove such a lock manually (e.g., after a power failure).
−
pct create 999 local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz
+
# pct unlock &lt;CTID&gt;
−
Proxmox VE itself ships a set of basic templates for most common
+
Only do this if you are sure the action which set the lock is no
−
operating systems, and you can download them using the pveam (short
+
longer running.
−
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
 
−
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.
 
−
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.
 
−
Mount Points
 
−
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=]&lt;volume&gt; [,acl=&lt;1|0&gt;] [,quota=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
 
−
mp[n]: [volume=]&lt;volume&gt; ,mp=&lt;Path&gt; [,acl=&lt;1|0&gt;] [,backup=&lt;1|0&gt;] [,quota=&lt;1|0&gt;] [,ro=&lt;1|0&gt;] [,size=&lt;DiskSize&gt;]
 
−
acl: boolean
 
−
Explicitly enable or disable ACL support.
 
−
backup: boolean
 
−
Whether to include the mountpoint in backups (only used for volume mountpoints).
 
−
mp: &lt;Path&gt;
 
−
Path to the mountpoint as seen from inside the container.
 
−
Must not contain any symlinks for security reasons.
 
−
quota: boolean
 
−
Enable user quotas inside the container (not supported with zfs subvolumes)
 
−
ro: boolean
 
−
Read-only mountpoint
 
−
size: &lt;DiskSize&gt;
 
−
Volume size (read only value).
 
−
volume: &lt;volume&gt;
 
−
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.
 
−
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.
 
−
The contents of bind mount points are not backed up when using vzdump.
 
−
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.
 
−
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&#8217;s
 
−
storage subsystem, but the quota and acl options will be honored.
 
−
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.
 
−
The contents of device mount points are not backed up when using vzdump.
 
−
FUSE Mounts
 
−
Because of existing issues in the Linux kernel&#8217;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.
 
−
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.
 
−
You need to run the above commands for every mount point by passing
 
−
the mount point&#8217;s path instead of just /.
 
−
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.
 
−
Container Network
 
−
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=&lt;string&gt; [,bridge=&lt;bridge&gt;] [,firewall=&lt;1|0&gt;] [,gw=&lt;GatewayIPv4&gt;] [,gw6=&lt;GatewayIPv6&gt;] [,hwaddr=&lt;XX:XX:XX:XX:XX:XX&gt;] [,ip=&lt;IPv4Format/CIDR&gt;] [,ip6=&lt;IPv6Format/CIDR&gt;] [,mtu=&lt;integer&gt;] [,rate=&lt;mbps&gt;] [,tag=&lt;integer&gt;] [,trunks=&lt;vlanid[;vlanid...]&gt;] [,type=&lt;veth&gt;]
 
−
bridge: &lt;bridge&gt;
 
−
Bridge to attach the network device to.
 
−
firewall: boolean
 
−
Controls whether this interface&#8217;s firewall rules should be used.
 
−
gw: &lt;GatewayIPv4&gt;
 
−
Default gateway for IPv4 traffic.
 
−
gw6: &lt;GatewayIPv6&gt;
 
−
Default gateway for IPv6 traffic.
 
−
hwaddr: &lt;XX:XX:XX:XX:XX:XX&gt;
 
−
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: &lt;IPv4Format/CIDR&gt;
 
−
IPv4 address in CIDR format.
 
−
ip6: &lt;IPv6Format/CIDR&gt;
 
−
IPv6 address in CIDR format.
 
−
mtu: integer (64 - N)
 
−
Maximum transfer unit of the interface. (lxc.network.mtu)
 
−
name: &lt;string&gt;
 
−
Name of the network device as seen from inside the container. (lxc.network.name)
 
−
rate: &lt;mbps&gt;
 
−
Apply rate limiting to the interface
 
−
tag: integer (1 - 4094)
 
−
VLAN tag for this interface.
 
−
trunks: &lt;vlanid[;vlanid...]&gt;
 
−
VLAN ids to pass through the interface
 
−
type: (veth)
 
−
Network interface type.
 
−
Backup and Restore
 
−
Container Backup
 
−
It is possible to use the vzdump tool for container backup. Please
 
−
refer to the vzdump manual page for details.
 
−
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).
 
−
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:
 
−
&#8220;Simple&#8221; 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:
 
−
Extract mount points and their options from backup
 
−
Create volumes for storage backed mount points (on storage provided with the
 
−
storage parameter, or default local storage if unset)
 
−
Extract files from backup archive
 
−
Add bind and device mount points to restored configuration (limited to root user)
 
−
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.
 
−
&#8220;Advanced&#8221; 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)
 
−
Managing Containers with pct
 
−
pct is the tool to manage Linux Containers on Proxmox VE. You can create
 
−
and destroy containers, and control execution (start, stop, migrate,
 
−
&#8230;). You can use pct to set parameters in the associated config file,
 
−
like network configuration or memory limits.
 
−
CLI Usage Examples
 
−
Create a container based on a Debian template (provided you have
 
−
already downloaded the template via the web interface)
 
−
pct create 100 /var/lib/vz/template/cache/debian-8.0-standard_8.0-1_amd64.tar.gz
 
−
Start container 100
 
−
pct start 100
 
−
Start a login session via getty
 
−
pct console 100
 
−
Enter the LXC namespace and run a shell as root user
 
−
pct enter 100
 
−
Display the configuration
 
−
pct config 100
 
−
Add a network interface called eth0, bridged to the host bridge vmbr0,
 
−
set the address and gateway, while it&#8217;s running
 
−
pct set 100 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.147/24,gw=192.168.15.1
 
−
Reduce the memory of the container to 512MB
 
−
pct set 100 -memory 512
 
−
Obtaining Debugging Logs
 
−
In case pct start is unable to start a specific container, it might be
 
−
helpful to collect debugging output by running lxc-start (replace ID with
 
−
the container&#8217;s ID):
 
−
lxc-start -n ID -F -l DEBUG -o /tmp/lxc-ID.log
 
−
This command will attempt to start the container in foreground mode, to stop the container run pct shutdown ID or pct stop ID in a second terminal.
 
−
The collected debug log is written to /tmp/lxc-ID.log.
 
−
If you have changed the container&#8217;s configuration since the last start
 
−
attempt with pct start, you need to run pct start at least once to also
 
−
update the configuration used by lxc-start.
 
−
Files
 
−
/etc/pve/lxc/&lt;CTID&gt;.conf
 
−
Configuration file for the container &lt;CTID&gt;.
 
−
Container Advantages
 
−
Simple, and fully integrated into Proxmox VE. Setup looks similar to a normal
 
−
  VM setup.
 
−
Storage (ZFS, LVM, NFS, Ceph, &#8230;)
 
−
Network
 
−
Authentication
 
−
Cluster
 
−
Fast: minimal overhead, as fast as bare metal
 
−
High density (perfect for idle workloads)
 
−
REST API
 
−
Direct hardware access
 
−
Technology Overview
 
−
Integrated into Proxmox VE graphical user interface (GUI)
 
−
LXC (https://linuxcontainers.org/)
 
−
lxcfs to provide containerized /proc file system
 
−
AppArmor
 
−
CRIU: for live migration (planned)
 
−
We use latest available kernels (4.4.X)
 
−
Image based deployment (templates)
 
−
Container setup from host (network, DNS, storage, &#8230;)
 
 
</pvehide>
 
</pvehide>
 
<!--PVE_IMPORT_END_MARKER-->
 
<!--PVE_IMPORT_END_MARKER-->
  
−
 
−
 
−
 
−
=== Security ===
 
−
LXC Containers use an AppArmor profile to provide ressource isolation in the container. This works by blocking system calls
 
−
like 'mount' who are denied being executed in the container.
 
−
You can trace the AppArmor activity with:
 
−
 
−
dmesg | grep apparmor
 
−
 
−
If you want to disable AppArmor for a container, you can add the stanza
 
−
 
−
lxc.aa_profile = unconfined
 
−
 
−
at the end of the configuration file ( located in /etc/pve/lxc/CTID.conf ) Note that this is not a recommended setup for production.
 
  
  
Line 584: Line 901:
 
* [https://github.com/lxc GIT Linux Container]
 
* [https://github.com/lxc GIT Linux Container]
  
−
[[Category:Installation]][[Category:Technology]][[Category:HOWTO]]
+
[[Category:Installation]][[Category:HOWTO]]

Revision as of 09:27, 17 November 2021

Containers are a lightweight alternative to fully virtualized machines (VMs). They use the kernel of the host system that they run on, instead of emulating a full operating system (OS). This means that containers can access resources on the host system directly.

The runtime costs for containers is low, usually negligible. However, there are some drawbacks that need be considered:

  • Only Linux distributions can be run in Proxmox Containers. It is not possible to run other operating systems like, for example, FreeBSD or Microsoft Windows inside a container.

  • For security reasons, access to host resources needs to be restricted. Therefore, containers run in their own separate namespaces. Additionally some syscalls (user space requests to the Linux kernel) are not allowed within containers.

Proxmox VE uses Linux Containers (LXC) as its underlying container technology. The “Proxmox Container Toolkit” (pct) simplifies the usage and management of LXC, by providing an interface that abstracts complex tasks.

Containers are tightly integrated with Proxmox VE. This means that they are aware of the cluster setup, and they can use the same network and storage resources as virtual machines. You can also use the Proxmox VE firewall, or manage containers using the HA framework.

Our primary goal is to offer an environment that provides the benefits of using a VM, but without the additional overhead. This means that Proxmox Containers can be categorized as “System Containers”, rather than “Application Containers”.

Note If you want to run application containers, for example, Docker images, it is recommended that you run them inside a Proxmox QEMU VM. This will give you all the advantages of application containerization, while also providing the benefits that VMs offer, such as strong isolation from the host and the ability to live-migrate, which otherwise isn’t possible with containers.

Technology Overview

  • LXC (https://linuxcontainers.org/)

  • Integrated into Proxmox VE graphical web user interface (GUI)

  • Easy to use command-line tool pct

  • Access via Proxmox VE REST API

  • lxcfs to provide containerized /proc file system

  • Control groups (cgroups) for resource isolation and limitation

  • AppArmor and seccomp to improve security

  • Modern Linux kernels

  • Image based deployment (templates)

  • Uses Proxmox VE storage library

  • Container setup from host (network, DNS, storage, etc.)

Supported Distributions

List of officially supported distributions can be found below.

Templates for the following distributions are available through our repositories. You can use pveam tool or the Graphical User Interface to download them.

Alpine Linux

Alpine Linux is a security-oriented, lightweight Linux distribution based on musl libc and busybox.

— https://alpinelinux.org

For currently supported releases see:

https://alpinelinux.org/releases/

Arch Linux

Arch Linux, a lightweight and flexible Linux® distribution that tries to Keep It Simple.

— https://archlinux.org/

Arch Linux is using a rolling-release model, see its wiki for more details:

https://wiki.archlinux.org/title/Arch_Linux

CentOS, Almalinux, Rocky Linux

CentOS / CentOS Stream

The CentOS Linux distribution is a stable, predictable, manageable and reproducible platform derived from the sources of Red Hat Enterprise Linux (RHEL)

— https://centos.org

For currently supported releases see:

https://en.wikipedia.org/wiki/CentOS#End-of-support_schedule

Almalinux

An Open Source, community owned and governed, forever-free enterprise Linux distribution, focused on long-term stability, providing a robust production-grade platform. AlmaLinux OS is 1:1 binary compatible with RHEL® and pre-Stream CentOS.

— https://almalinux.org

For currently supported releases see:

https://en.wikipedia.org/wiki/AlmaLinux#Releases

Rocky Linux

Rocky Linux is a community enterprise operating system designed to be 100% bug-for-bug compatible with America’s top enterprise Linux distribution now that its downstream partner has shifted direction.

— https://rockylinux.org

For currently supported releases see:

https://en.wikipedia.org/wiki/Rocky_Linux#Releases

Debian

Debian is a free operating system, developed and maintained by the Debian project. A free Linux distribution with thousands of applications to meet our users' needs.

— https://www.debian.org/intro/index#software

For currently supported releases see:

https://www.debian.org/releases/stable/releasenotes

Devuan

Devuan GNU+Linux is a fork of Debian without systemd that allows users to reclaim control over their system by avoiding unnecessary entanglements and ensuring Init Freedom.

— https://www.devuan.org

For currently supported releases see:

https://www.devuan.org/os/releases

Fedora

Fedora creates an innovative, free, and open source platform for hardware, clouds, and containers that enables software developers and community members to build tailored solutions for their users.

— https://getfedora.org

For currently supported releases see:

https://fedoraproject.org/wiki/Releases

Gentoo

a highly flexible, source-based Linux distribution.

— https://www.gentoo.org

Gentoo is using a rolling-release model.

OpenSUSE

The makers' choice for sysadmins, developers and desktop users.

— https://www.opensuse.org

For currently supported releases see:

https://get.opensuse.org/leap/

Ubuntu

Ubuntu is the modern, open source operating system on Linux for the enterprise server, desktop, cloud, and IoT.

— https://ubuntu.com/

For currently supported releases see:

https://wiki.ubuntu.com/Releases

Container Images

Container images, sometimes also referred to as “templates” or “appliances”, are tar archives which contain everything to run a container.

Proxmox VE itself provides a variety of basic templates for the most common Linux distributions. They can be downloaded using the GUI or the pveam (short for Proxmox VE Appliance Manager) command-line utility. Additionally, TurnKey Linux container templates are also available to download.

The list of available templates is updated daily through the pve-daily-update timer. You can also trigger an update manually by executing:

# pveam update

To view the list of available images run:

# 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          alpine-3.12-default_20200823_amd64.tar.xz
system          alpine-3.13-default_20210419_amd64.tar.xz
system          alpine-3.14-default_20210623_amd64.tar.xz
system          archlinux-base_20210420-1_amd64.tar.gz
system          centos-7-default_20190926_amd64.tar.xz
system          centos-8-default_20201210_amd64.tar.xz
system          debian-9.0-standard_9.7-1_amd64.tar.gz
system          debian-10-standard_10.7-1_amd64.tar.gz
system          devuan-3.0-standard_3.0_amd64.tar.gz
system          fedora-33-default_20201115_amd64.tar.xz
system          fedora-34-default_20210427_amd64.tar.xz
system          gentoo-current-default_20200310_amd64.tar.xz
system          opensuse-15.2-default_20200824_amd64.tar.xz
system          ubuntu-16.04-standard_16.04.5-1_amd64.tar.gz
system          ubuntu-18.04-standard_18.04.1-1_amd64.tar.gz
system          ubuntu-20.04-standard_20.04-1_amd64.tar.gz
system          ubuntu-20.10-standard_20.10-1_amd64.tar.gz
system          ubuntu-21.04-standard_21.04-1_amd64.tar.gz

Before you can use such a template, you need to download them into one of your storages. If you’re unsure to which one, you can simply use the local named storage 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-10.0-standard_10.0-1_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-10.0-standard_10.0-1_amd64.tar.gz  219.95MB
Tip You can also use the Proxmox VE web interface GUI to download, list and delete container templates.

pct uses them to create a new container, for example:

# pct create 999 local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz

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-10.0-standard_10.0-1_amd64.tar.gz

Container Settings

General Settings

screenshot/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.

Unprivileged Containers

Unprivileged 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, etc.) in these containers will affect a random unprivileged user, and would be a generic kernel security bug rather than an LXC issue. The LXC team thinks unprivileged containers are safe by design.

This is the default option when creating a new container.

Note If the container uses systemd as an init system, please be aware the systemd version running inside the container should be equal to or greater than 220.

Privileged Containers

Security in containers is achieved by using mandatory access control AppArmor restrictions, seccomp filters and Linux kernel 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. That’s why privileged containers should only be used in trusted environments.

CPU

screenshot/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 periodically. To view the assigned CPUs run the following command:

# pct cpusets
 ---------------------
 102:              6 7
 105:      2 3 4 5
 108:  0 1
 ---------------------

Containers use the host kernel directly. All tasks 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 100 (or 1024 if the host uses legacy cgroup v1). You can use this setting to prioritize some containers.

Memory

screenshot/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).

Mount Points

screenshot/gui-create-ct-root-disk.png

The root mount point is configured with the rootfs property. You can configure up to 256 additional mount points. The corresponding options are called mp0 to mp255. They can contain the following settings:

rootfs: [volume=]<volume> [,acl=<1|0>] [,mountoptions=<opt[;opt...]>] [,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>] [,mountoptions=<opt[;opt...]>] [,quota=<1|0>] [,replicate=<1|0>] [,ro=<1|0>] [,shared=<1|0>] [,size=<DiskSize>]

Use volume as container mount point. Use the special syntax STORAGE_ID:SIZE_IN_GiB to allocate a new volume.

acl=<boolean>

Explicitly enable or disable ACL support.

backup=<boolean>

Whether to include the mount point in backups (only used for volume mount points).

mountoptions=<opt[;opt...]>

Extra mount options for rootfs/mps.

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 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. For example, 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, and setup the moutpoint in the container at /path/in/container

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, add a configuration line such as:

mp0: /mnt/bindmounts/shared,mp=/shared

into /etc/pve/lxc/100.conf.

Or alternatively use the pct tool:

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.

Network

screenshot/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)>] [,link_down=<1|0>] [,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>

A common MAC address with the I/G (Individual/Group) bit not set.

ip=<(IPv4/CIDR|dhcp|manual)>

IPv4 address in CIDR format.

ip6=<(IPv6/CIDR|auto|dhcp|manual)>

IPv6 address in CIDR format.

link_down=<boolean>

Whether this interface should be disconnected (like pulling the plug).

mtu=<integer> (64 - 65535)

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.

Automatic Start and Shutdown of Containers

To automatically start a container when the host system boots, select the option Start at boot in the Options panel of the container in the web interface or run the following command:

# pct set CTID -onboot 1
screenshot/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. For example, 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. For example, 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.

If you require a delay between the host boot and the booting of the first container, see the section on Proxmox VE Node Management.

Hookscripts

You can add a hook script to CTs with the config property hookscript.

# pct set 100 -hookscript local:snippets/hookscript.pl

It will be called during various phases of the guests lifetime. For an example and documentation see the example script under /usr/share/pve-docs/examples/guest-example-hookscript.pl.

Security Considerations

Containers use the kernel of the host system. This exposes an attack surface for malicious users. In general, full virtual machines provide better isolation. This should be considered if containers are provided to unknown or untrusted people.

To reduce the attack surface, LXC uses many security features like AppArmor, CGroups and kernel namespaces.

AppArmor

AppArmor profiles are used to restrict access to possibly dangerous actions. Some system calls, i.e. mount, are prohibited from execution.

To trace AppArmor activity, use:

# dmesg | grep apparmor

Although it is not recommended, AppArmor can be disabled for a container. This brings security risks with it. Some syscalls can lead to privilege escalation when executed within a container if the system is misconfigured or if a LXC or Linux Kernel vulnerability exists.

To disable AppArmor for a container, add the following line to the container configuration file located at /etc/pve/lxc/CTID.conf:

lxc.apparmor.profile = unconfined
Warning Please note that this is not recommended for production use.

Control Groups (cgroup)

cgroup is a kernel mechanism used to hierarchically organize processes and distribute system resources.

The main resources controlled via cgroups are CPU time, memory and swap limits, and access to device nodes. cgroups are also used to "freeze" a container before taking snapshots.

There are 2 versions of cgroups currently available, legacy and cgroupv2.

Since Proxmox VE 7.0, the default is a pure cgroupv2 environment. Previously a "hybrid" setup was used, where resource control was mainly done in cgroupv1 with an additional cgroupv2 controller which could take over some subsystems via the cgroup_no_v1 kernel command-line parameter. (See the kernel parameter documentation for details.)

CGroup Version Compatibility

The main difference between pure cgroupv2 and the old hybrid environments regarding Proxmox VE is that with cgroupv2 memory and swap are now controlled independently. The memory and swap settings for containers can map directly to these values, whereas previously only the memory limit and the limit of the sum of memory and swap could be limited.

Another important difference is that the devices controller is configured in a completely different way. Because of this, file system quotas are currently not supported in a pure cgroupv2 environment.

cgroupv2 support by the container’s OS is needed to run in a pure cgroupv2 environment. Containers running systemd version 231 or newer support cgroupv2
[this includes all newest major versions of container templates shipped by Proxmox VE]
, as do containers not using systemd as init system
[for example Alpine Linux]
.

Note

CentOS 7 and Ubuntu 16.10 are two prominent Linux distributions releases, which have a systemd version that is too old to run in a cgroupv2 environment, you can either

  • Upgrade the whole distribution to a newer release. For the examples above, that could be Ubuntu 18.04 or 20.04, and CentOS 8 (or RHEL/CentOS derivatives like AlmaLinux or Rocky Linux). This has the benefit to get the newest bug and security fixes, often also new features, and moving the EOL date in the future.

  • Upgrade the Containers systemd version. If the distribution provides a backports repository this can be an easy and quick stop-gap measurement.

  • Move the container, or its services, to a Virtual Machine. Virtual Machines have a much less interaction with the host, that’s why one can install decades old OS versions just fine there.

  • Switch back to the legacy cgroup controller. Note that while it can be a valid solution, it’s not a permanent one. Starting from Proxmox VE 9.0, the legacy controller will not be supported anymore.

Changing CGroup Version

Tip If file system quotas are not required and all containers support cgroupv2, it is recommended to stick to the new default.

To switch back to the previous version the following kernel command-line parameter can be used:

systemd.unified_cgroup_hierarchy=0

See this section on editing the kernel boot command line on where to add the parameter.

Guest Operating System Configuration

Proxmox VE tries to detect the Linux distribution in the container, and modifies some files. Here is a short list of things done 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. Proxmox VE first checks the /etc/os-release file
[/etc/os-release replaces the multitude of per-distribution release files https://manpages.debian.org/stable/systemd/os-release.5.en.html]
. If that file is not present, or it does not contain a clearly recognizable distribution identifier the following distribution specific release files are checked.

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.

Container Storage

The Proxmox VE LXC container storage model is more flexible than traditional container storage models. A container can have multiple mount points. This makes it possible to use the best suited storage for each application.

For example the root file system of the container can be on slow and cheap storage while the database can be on fast and distributed storage via a second mount point. See section Mount Points for further details.

Any storage type supported by the Proxmox VE storage library can be used. This means that containers can be stored on local (for example lvm, zfs or directory), shared external (like iSCSI, NFS) or even distributed storage systems like Ceph. Advanced storage features like snapshots or clones can be used if the underlying storage supports them. The vzdump backup tool can use snapshots to provide consistent container backups.

Furthermore, local devices or local directories can be mounted directly using bind mounts. This gives access to local resources inside a container with practically zero overhead. Bind mounts can be used as an easy way to share data between containers.

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.

Using Quotas Inside Containers

Quotas allow to set limits inside a container for the amount of disk space that each user can use.

Note This currently requires the use of legacy cgroups.
Note This only works on ext4 image based storage types and currently only works with privileged 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 on any other system. You can initialize the /aquota.user and /aquota.group files by running:

# quotacheck -cmug /
# quotaon /

Then edit the quotas using 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 /.

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.

Backup of Container mount points

To include a mount point in backups, enable the backup option for it in the container configuration. For an existing mount point mp0

mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G

add backup=1 to enable it.

mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G,backup=1
Note When creating a new mount point in the GUI, this option is enabled by default.

To disable backups for a mount point, add backup=0 in the way described above, or uncheck the Backup checkbox on the GUI.

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, you can set the Skip replication option for that mount point. As of Proxmox VE 5.0, replication requires a storage of type zfspool. Adding a mount point to a different type of storage when the container has replication configured requires to have Skip replication enabled for that mount point.

Backup and Restore

Container Backup

It is possible to use the vzdump tool for container backup. Please refer to the vzdump manual page for details.

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 the storage provided with the storage parameter (default: local).

  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)

Managing Containers with pct

The “Proxmox Container Toolkit” (pct) is the command-line tool to manage Proxmox VE containers. It enables you to create or destroy containers, as well as control the container execution (start, stop, reboot, migrate, etc.). It can be used to set parameters in the config file of a container, for example the network configuration or memory limits.

CLI Usage Examples

Create a container based on a Debian template (provided you have already downloaded the template via the web interface)

# pct create 100 /var/lib/vz/template/cache/debian-10.0-standard_10.0-1_amd64.tar.gz

Start container 100

# pct start 100

Start a login session via getty

# pct console 100

Enter the LXC namespace and run a shell as root user

# pct enter 100

Display the configuration

# pct config 100

Add a network interface called eth0, bridged to the host bridge vmbr0, set the address and gateway, while it’s running

# pct set 100 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.147/24,gw=192.168.15.1

Reduce the memory of the container to 512MB

# pct set 100 -memory 512

Destroying a container always removes it from Access Control Lists and it always removes the firewall configuration of the container. You have to activate --purge, if you want to additionally remove the container from replication jobs, backup jobs and HA resource configurations.

# pct destroy 100 --purge

Move a mount point volume to a different storage.

# pct move-volume 100 mp0 other-storage

Reassign a volume to a different CT. This will remove the volume mp0 from the source CT and attaches it as mp1 to the target CT. In the background the volume is being renamed so that the name matches the new owner.

#  pct move-volume 100 mp0 --target-vmid 200 --target-volume mp1

Obtaining Debugging Logs

In case pct start is unable to start a specific container, it might be helpful to collect debugging output by passing the --debug flag (replace CTID with the container’s CTID):

# pct start CTID --debug

Alternatively, you can use the following lxc-start command, which will save the debug log to the file specified by the -o output option:

# lxc-start -n CTID -F -l DEBUG -o /tmp/lxc-CTID.log

This command will attempt to start the container in foreground mode, to stop the container run pct shutdown CTID or pct stop CTID in a second terminal.

The collected debug log is written to /tmp/lxc-CTID.log.

Note If you have changed the container’s configuration since the last start attempt with pct start, you need to run pct start at least once to also update the configuration used by lxc-start.

Migration

If you have a cluster, you can migrate your Containers with

# pct migrate <ctid> <target>

This works as long as your Container is offline. If it has local volumes or mount points defined, the migration will copy the content over the network to the target host if the same storage is defined there.

Running containers cannot live-migrated due to technical limitations. You can do a restart migration, which shuts down, moves and then starts a container again on the target node. As containers are very lightweight, this results normally only in a downtime of some hundreds of milliseconds.

A restart migration can be done through the web interface or by using the --restart flag with the pct migrate command.

A restart migration will shut down the Container and kill it after the specified timeout (the default is 180 seconds). Then it will migrate the Container like an offline migration and when finished, it starts the Container on the target node.

Configuration

The /etc/pve/lxc/<CTID>.conf file stores container configuration, where <CTID> is the numeric ID of the given container. Like all other files stored inside /etc/pve/, they get automatically replicated to all other cluster nodes.

Note CTIDs < 100 are reserved for internal purposes, and CTIDs need to be unique cluster wide.
Example Container Configuration
ostype: debian
arch: amd64
hostname: www
memory: 512
swap: 512
net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
rootfs: local:107/vm-107-disk-1.raw,size=7G

The configuration files are simple text files. You can edit them using a normal text editor, for example, vi or nano. This is sometimes useful to do small corrections, but keep in mind that you need to restart the container to apply such changes.

For that reason, it is usually better to use the pct 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 containers. This feature is called “hot plug”, and there is no need to restart the container in that case.

In cases where a change cannot be hot-plugged, it will be registered as a pending change (shown in red color in the GUI). They will only be applied after rebooting the container.

File Format

The container configuration file uses 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.

It is possible to add low-level, LXC style configuration directly, for example:

lxc.init_cmd: /sbin/my_own_init

or

lxc.init_cmd = /sbin/my_own_init

The settings are passed directly to the LXC low-level tools.

Snapshots

When you create a snapshot, pct 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:

Container 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).

Options

arch: <amd64 | arm64 | armhf | i386 | riscv32 | riscv64> (default = amd64)

OS architecture type.

cmode: <console | shell | tty> (default = tty)

Console mode. By default, the console command tries to open a connection to one of the available tty devices. By setting cmode to console it tries to attach to /dev/console instead. If you set cmode to shell, it simply invokes a shell inside the container (no login).

console: <boolean> (default = 1)

Attach a console device (/dev/console) to the container.

cores: <integer> (1 - 8192)

The number of cores assigned to the container. A container can use all available cores by default.

cpulimit: <number> (0 - 8192) (default = 0)

Limit of CPU usage.

Note If the computer has 2 CPUs, it has a total of 2 CPU time. Value 0 indicates no CPU limit.
cpuunits: <integer> (0 - 500000) (default = cgroup v1: 1024, cgroup v2: 100)

CPU weight for a container. Argument is used in the kernel fair scheduler. The larger the number is, the more CPU time this container gets. Number is relative to the weights of all the other running guests.

debug: <boolean> (default = 0)

Try to be more verbose. For now this only enables debug log-level on start.

description: <string>

Description for the Container. Shown in the web-interface CT’s summary. This is saved as comment inside the configuration file.

dev[n]: [[path=]<Path>] [,gid=<integer>] [,mode=<Octal access mode>] [,uid=<integer>]

Device to pass through to the container

gid=<integer> (0 - N)

Group ID to be assigned to the device node

mode=<Octal access mode>

Access mode to be set on the device node

path=<Path>

Path to the device to pass through to the container

uid=<integer> (0 - N)

User ID to be assigned to the device node

features: [force_rw_sys=<1|0>] [,fuse=<1|0>] [,keyctl=<1|0>] [,mknod=<1|0>] [,mount=<fstype;fstype;...>] [,nesting=<1|0>]

Allow containers access to advanced features.

force_rw_sys=<boolean> (default = 0)

Mount /sys in unprivileged containers as rw instead of mixed. This can break networking under newer (>= v245) systemd-network use.

fuse=<boolean> (default = 0)

Allow using fuse file systems in a container. Note that interactions between fuse and the freezer cgroup can potentially cause I/O deadlocks.

keyctl=<boolean> (default = 0)

For unprivileged containers only: Allow the use of the keyctl() system call. This is required to use docker inside a container. By default unprivileged containers will see this system call as non-existent. This is mostly a workaround for systemd-networkd, as it will treat it as a fatal error when some keyctl() operations are denied by the kernel due to lacking permissions. Essentially, you can choose between running systemd-networkd or docker.

mknod=<boolean> (default = 0)

Allow unprivileged containers to use mknod() to add certain device nodes. This requires a kernel with seccomp trap to user space support (5.3 or newer). This is experimental.

mount=<fstype;fstype;...>

Allow mounting file systems of specific types. This should be a list of file system types as used with the mount command. Note that this can have negative effects on the container’s security. With access to a loop device, mounting a file can circumvent the mknod permission of the devices cgroup, mounting an NFS file system can block the host’s I/O completely and prevent it from rebooting, etc.

nesting=<boolean> (default = 0)

Allow nesting. Best used with unprivileged containers with additional id mapping. Note that this will expose procfs and sysfs contents of the host to the guest.

hookscript: <string>

Script that will be exectued during various steps in the containers lifetime.

hostname: <string>

Set a host name for the container.

lock: <backup | create | destroyed | disk | fstrim | migrate | mounted | rollback | snapshot | snapshot-delete>

Lock/unlock the container.

memory: <integer> (16 - N) (default = 512)

Amount of RAM for the container in MB.

mp[n]: [volume=]<volume> ,mp=<Path> [,acl=<1|0>] [,backup=<1|0>] [,mountoptions=<opt[;opt...]>] [,quota=<1|0>] [,replicate=<1|0>] [,ro=<1|0>] [,shared=<1|0>] [,size=<DiskSize>]

Use volume as container mount point. Use the special syntax STORAGE_ID:SIZE_IN_GiB to allocate a new volume.

acl=<boolean>

Explicitly enable or disable ACL support.

backup=<boolean>

Whether to include the mount point in backups (only used for volume mount points).

mountoptions=<opt[;opt...]>

Extra mount options for rootfs/mps.

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.

nameserver: <string>

Sets DNS server IP address for a container. Create will automatically use the setting from the host if you neither set searchdomain nor nameserver.

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)>] [,link_down=<1|0>] [,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>

A common MAC address with the I/G (Individual/Group) bit not set.

ip=<(IPv4/CIDR|dhcp|manual)>

IPv4 address in CIDR format.

ip6=<(IPv6/CIDR|auto|dhcp|manual)>

IPv6 address in CIDR format.

link_down=<boolean>

Whether this interface should be disconnected (like pulling the plug).

mtu=<integer> (64 - 65535)

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.

onboot: <boolean> (default = 0)

Specifies whether a container will be started during system bootup.

ostype: <alpine | archlinux | centos | debian | devuan | fedora | gentoo | nixos | opensuse | ubuntu | unmanaged>

OS type. This is used to setup configuration inside the container, and corresponds to lxc setup scripts in /usr/share/lxc/config/<ostype>.common.conf. Value unmanaged can be used to skip and OS specific setup.

protection: <boolean> (default = 0)

Sets the protection flag of the container. This will prevent the CT or CT’s disk remove/update operation.

rootfs: [volume=]<volume> [,acl=<1|0>] [,mountoptions=<opt[;opt...]>] [,quota=<1|0>] [,replicate=<1|0>] [,ro=<1|0>] [,shared=<1|0>] [,size=<DiskSize>]

Use volume as container root.

acl=<boolean>

Explicitly enable or disable ACL support.

mountoptions=<opt[;opt...]>

Extra mount options for rootfs/mps.

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.

searchdomain: <string>

Sets DNS search domains for a container. Create will automatically use the setting from the host if you neither set searchdomain nor nameserver.

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.

swap: <integer> (0 - N) (default = 512)

Amount of SWAP for the container in MB.

tags: <string>

Tags of the Container. This is only meta information.

template: <boolean> (default = 0)

Enable/disable Template.

timezone: <string>

Time zone to use in the container. If option isn’t set, then nothing will be done. Can be set to host to match the host time zone, or an arbitrary time zone option from /usr/share/zoneinfo/zone.tab

tty: <integer> (0 - 6) (default = 2)

Specify the number of tty available to the container

unprivileged: <boolean> (default = 0)

Makes the container run as unprivileged user. (Should not be modified manually.)

unused[n]: [volume=]<volume>

Reference to unused volumes. This is used internally, and should not be modified manually.

volume=<volume>

The volume that is not used currently.

Locks

Container migrations, snapshots and backups (vzdump) set a lock to prevent incompatible concurrent actions on the affected container. Sometimes you need to remove such a lock manually (e.g., after a power failure).

# pct unlock <CTID>
Caution Only do this if you are sure the action which set the lock is no longer running.



Migrate container from OpenVZ to Linux container

Follow this howto:

References

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