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= Introduction  =
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<!--PVE_IMPORT_START_MARKER-->
 
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<!-- Do not edit - this is autogenerated content -->
<b>NOTE: BETA Technology preview</b>
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{{#pvedocs:pct-plain.html}}
 
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[[Category:Reference Documentation]]
A Linux Container is an operating-system-level virtualization environment for running multiple isolated Linux systems on a single Linux control host ([https://en.wikipedia.org/wiki/LXC Wikipedia LXC]). It can be also defined as a lightweight VM but extremely fast and easy to deploy.
+
<pvehide>
 
+
Containers are a lightweight alternative to fully virtualized
There is not much overhead and therefore it's the perfect solution for effective use of resources.
+
VMs. Instead of emulating a complete Operating System (OS), containers
 
+
simply use the OS of the host they run on. This implies that all
No extra kernel boot is necessary on startup resulting in a super fast boot.
+
containers use the same kernel, and that they can access resources
 
+
from the host directly.
Linux Containers are introduced in Proxmox VE 4.0 and support the [[Storage_Model |Proxmox Storage Model]].
+
This is great because containers do not waste CPU power nor memory due
 
+
to kernel emulation. Container run-time costs are close to zero and
= System requirements  =
+
usually negligible. But there are also some drawbacks you need to
*Proxmox VE 4.0 or higher
+
consider:
 
+
You can only run Linux based OS inside containers, i.e. it is not
=Features=
+
  possible to run FreeBSD or MS Windows inside.
*Support of local directories, NFS, ZFS, LVM (future support for Sheepdog, Ceph, iSCSI, DRBD and GlusterFS is planned)
+
For security reasons, access to host resources needs to be
*manipulate disk size
+
  restricted. This is done with AppArmor, SecComp filters and other
*<b>Coming soon:</b> snapshot, rollback, clone, linked clone (all these features need storage support)
+
  kernel features. Be prepared that some syscalls are not allowed
*Kernel namespaces (ipc, uts, mount, pid, network and user)
+
  inside containers.
*Apparmor profiles
+
Proxmox VE uses LXC as underlying container
*Seccomp policies
+
technology. We consider LXC as low-level library, which provides
*Chroots (using pivot_root)
+
countless options. It would be too difficult to use those tools
*Kernel capabilities
+
directly. Instead, we provide a small wrapper called pct, the
*CGroups (control groups)
+
"Proxmox Container Toolkit".
*Migration
+
The toolkit is tightly coupled with Proxmox VE. That means that it is aware
*Backup and restore
+
of the cluster setup, and it can use the same network and storage
*Integrated firewall
+
resources as fully virtualized VMs. You can even use the Proxmox VE
*Network support for VLAN, IPv4, IPv6
+
firewall, or manage containers using the HA framework.
 
+
Our primary goal is to offer an environment as one would get from a
=Supported OS=
+
VM, but without the additional overhead. We call this "System
*Debian 6, 7, 8
+
Containers".
*CentOS 6
+
If you want to run micro-containers (with docker, rkt, &#8230;), it
*Ubuntu 12.04, 14.04, 15.04
+
is best to run them inside a VM.
Other OS are following step by step.
+
Technology Overview
 
+
LXC (https://linuxcontainers.org/)
=Manage containers=
+
Integrated into Proxmox VE graphical user interface (GUI)
Management can be done either via the web gui, or via command line tools
+
Easy to use command line tool pct
==Get a container template==
+
Access via Proxmox VE REST API
All templates can be downloaded at the GUI.[[File:DownloadContainer.png|200px|thumb|rigth|DownloadContainer]]
+
lxcfs to provide containerized /proc file system
<b>NOTE: Only the supported OS work</b>
+
AppArmor/Seccomp to improve security
 
+
CRIU: for live migration (planned)
If the containers are not yet visible use the following pve command to update the list.
+
Runs on modern Linux kernels
<pre>
+
Image based deployment (templates)
 +
Use Proxmox VE storage library
 +
Container setup from host (network, DNS, storage, &#8230;)
 +
Security Considerations
 +
Containers use the same kernel as the host, so there is a big attack
 +
surface for malicious users. You should consider this fact if you
 +
provide containers to totally untrusted people. In general, fully
 +
virtualized VMs provide better isolation.
 +
The good news is that LXC uses many kernel security features like
 +
AppArmor, CGroups and PID and user namespaces, which makes containers
 +
usage quite secure.
 +
Guest Operating System Configuration
 +
We normally try to detect the operating system type inside the
 +
container, and then modify some files inside the container to make
 +
them work as expected. Here is a short list of things we do at
 +
container startup:
 +
set /etc/hostname
 +
to set the container name
 +
modify /etc/hosts
 +
to allow lookup of the local hostname
 +
network setup
 +
pass the complete network setup to the container
 +
configure DNS
 +
pass information about DNS servers
 +
adapt the init system
 +
for example, fix the number of spawned getty processes
 +
set the root password
 +
when creating a new container
 +
rewrite ssh_host_keys
 +
so that each container has unique keys
 +
randomize crontab
 +
so that cron does not start at the same time on all containers
 +
Changes made by Proxmox VE are enclosed by comment markers:
 +
# --- BEGIN PVE ---
 +
&lt;data&gt;
 +
# --- END PVE ---
 +
Those markers will be inserted at a reasonable location in the
 +
file. If such a section already exists, it will be updated in place
 +
and will not be moved.
 +
Modification of a file can be prevented by adding a .pve-ignore.
 +
file for it.  For instance, if the file /etc/.pve-ignore.hosts
 +
exists then the /etc/hosts file will not be touched. This can be a
 +
simple empty file created via:
 +
# touch /etc/.pve-ignore.hosts
 +
Most modifications are OS dependent, so they differ between different
 +
distributions and versions. You can completely disable modifications
 +
by manually setting the ostype to unmanaged.
 +
OS type detection is done by testing for certain files inside the
 +
container:
 +
Ubuntu
 +
inspect /etc/lsb-release (DISTRIB_ID=Ubuntu)
 +
Debian
 +
test /etc/debian_version
 +
Fedora
 +
test /etc/fedora-release
 +
RedHat or CentOS
 +
test /etc/redhat-release
 +
ArchLinux
 +
test /etc/arch-release
 +
Alpine
 +
test /etc/alpine-release
 +
Gentoo
 +
test /etc/gentoo-release
 +
Container start fails if the configured ostype differs from the auto
 +
detected type.
 +
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. You can think of it as a tidy container backup. Like most
 +
modern container toolkits, pct uses those images when you create a
 +
new container, for example:
 +
pct create 999 local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz
 +
Proxmox VE itself ships a set of basic templates for most common
 +
operating systems, and you can download them using the pveam (short
 +
for Proxmox VE Appliance Manager) command line utility. You can also
 +
download TurnKey Linux containers using
 +
that tool (or the graphical user interface).
 +
Our image repositories contain a list of available images, and there
 +
is a cron job run each day to download that list. You can trigger that
 +
update manually with:
 
pveam update
 
pveam update
</pre>
+
After that you can view the list of available images using:
 
+
pveam available
==Create container==
+
You can restrict this large list by specifying the section you are
To create a container you need a container template. described below![[File:Create CT.png|200px|thumb|rigth|Create CT]]
+
interested in, for example basic system images:
A GUI wizard will guide you through the creation process.
+
List available system images
 
+
# pveam available --section system
It is also possible to create a container with the pct command line tool.
+
system          archlinux-base_2015-24-29-1_x86_64.tar.gz
More details see manpages
+
system          centos-7-default_20160205_amd64.tar.xz
<pre>
+
system          debian-6.0-standard_6.0-7_amd64.tar.gz
pct create 112 /var/lib/vz/template/cache/debian-7.0-standard_7.0-2_i386.tar.gz \
+
system          debian-7.0-standard_7.0-3_amd64.tar.gz
  -description LXC -disk 4 -hostname pvecontainer01 -memory 1024 -nameserver 8.8.8.8 \
+
system          debian-8.0-standard_8.0-1_amd64.tar.gz
  -net0 hwaddr=52:4A:5E:26:58:D7,ip=192.168.15.83/24,gw=192.168.15.1,bridge=vmbr0 \
+
system          ubuntu-12.04-standard_12.04-1_amd64.tar.gz
  -storage local -password changeme
+
system          ubuntu-14.04-standard_14.04-1_amd64.tar.gz
</pre>
+
system          ubuntu-15.04-standard_15.04-1_amd64.tar.gz
 
+
system          ubuntu-15.10-standard_15.10-1_amd64.tar.gz
==Start container==
+
Before you can use such a template, you need to download them into one
There are two possibilities to start a container:
+
of your storages. You can simply use storage local for that
either on the GUI or on the command line [[File:Start_CT.png|200px|thumb|rigth|Start Container]]
+
purpose. For clustered installations, it is preferred to use a shared
<pre>
+
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. See section Mount Points for further
 +
details.
 +
The second big improvement is that you can use any storage type
 +
supported by the Proxmox VE storage library. That means that you can store
 +
your containers on local lvmthin or zfs, shared iSCSI storage,
 +
or even on distributed storage systems like ceph. It also enables us
 +
to use advanced storage features like snapshots and clones. vzdump
 +
can also use the snapshot feature to provide consistent container
 +
backups.
 +
Last but not least, you can also mount local devices directly, or
 +
mount local directories using bind mounts. That way you can access
 +
local storage inside containers with zero overhead. Such bind mounts
 +
also provide an easy way to share data between different containers.
 +
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.
 +
Backup of Containers mount points
 +
By default additional mount points besides the Root Disk mount point are not
 +
included in backups. You can reverse this default behavior by setting the
 +
Backup option on a mount point.
 +
Replication of Containers mount points
 +
By default additional mount points are replicated when the Root Disk
 +
is replicated. If you want the Proxmox VE storage replication mechanism to skip a
 +
mount point when starting  a replication job, you can set the
 +
Skip replication option on that mount point.
 +
As of Proxmox VE 5.0, replication requires a storage of type zfspool, so adding a
 +
mount point to a different type of storage when the container has replication
 +
configured requires to Skip replication for that mount point.
 +
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.
 +
Privileged Containers
 +
Security is done by dropping capabilities, using mandatory access
 +
control (AppArmor), SecComp filters and namespaces. The LXC team
 +
considers this kind of container as unsafe, and they will not consider
 +
new container escape exploits to be security issues worthy of a CVE
 +
and quick fix. So you should use this kind of containers only inside a
 +
trusted environment, or when no untrusted task is running as root in
 +
the container.
 +
Unprivileged Containers
 +
This kind of containers use a new kernel feature called user
 +
namespaces. The root UID 0 inside the container is mapped to an
 +
unprivileged user outside the container. This means that most security
 +
issues (container escape, resource abuse, &#8230;) in those containers
 +
will affect a random unprivileged user, and so would be a generic
 +
kernel security bug rather than an LXC issue. The LXC team thinks
 +
unprivileged containers are safe by design.
 +
If the container uses systemd as an init system, please be
 +
aware the systemd version running inside the container should be equal
 +
or greater than 220.
 +
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. You can view
 +
the assigned CPUs using the following command:
 +
# pct cpusets
 +
---------------------
 +
102:              6 7
 +
105:      2 3 4 5
 +
108:  0 1
 +
---------------------
 +
Containers use the host kernel directly, so all task inside a
 +
container are handled by the host CPU scheduler. Proxmox VE uses the Linux
 +
CFS (Completely Fair Scheduler) scheduler by default,
 +
which has additional bandwidth control options.
 +
cpulimit:
 +
You can use this option to further limit assigned CPU
 +
time. Please note that this is a floating point number, so it is
 +
perfectly valid to assign two cores to a container, but restrict
 +
overall CPU consumption to half a core.
 +
cores: 2
 +
cpulimit: 0.5
 +
cpuunits:
 +
This is a relative weight passed to the kernel
 +
scheduler. The larger the number is, the more CPU time this container
 +
gets. Number is relative to the weights of all the other running
 +
containers. The default is 1024. You can use this setting to
 +
prioritize some containers.
 +
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, 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;] [,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.
 +
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 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.
 +
The special option syntax STORAGE_ID:SIZE_IN_GB for storage backed
 +
mount point volumes will automatically allocate a volume of the specified size
 +
on the specified storage. E.g., calling
 +
pct set 100 -mp0 thin1:10,mp=/path/in/container will allocate a 10GB volume
 +
on the storage thin1 and replace the volume ID place holder 10 with the
 +
allocated volume ID.
 +
Bind Mount Points
 +
Bind mounts allow you to access arbitrary directories from your Proxmox VE host
 +
inside a container. Some potential use cases are:
 +
Accessing your home directory in the guest
 +
Accessing an USB device directory in the guest
 +
Accessing an NFS mount from the host in the guest
 +
Bind mounts are considered to not be managed by the storage subsystem, so you
 +
cannot make snapshots or deal with quotas from inside the container. With
 +
unprivileged containers you might run into permission problems caused by the
 +
user mapping and cannot use ACLs.
 +
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
 +
After creating your containers, you probably want them to start automatically
 +
when the host system boots. For this you need to select the option Start at
 +
boot from the Options Tab of your container in the web interface, or set it with
 +
the following command:
 +
pct set &lt;ctid&gt; -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. E.g. set it to 1 if
 +
you want the CT to be the first to be started. (We use the reverse startup
 +
order for shutdown, so a container with a start order of 1 would be the last to
 +
be shut down)
 +
Startup delay: Defines the interval between this container start and subsequent
 +
containers starts . E.g. set it to 240 if you want to wait 240 seconds before starting
 +
other containers.
 +
Shutdown timeout: Defines the duration in seconds Proxmox VE should wait
 +
for the container to be offline after issuing a shutdown command.
 +
By default this value is set to 60, which means that Proxmox VE will issue a
 +
shutdown request, wait 60s for the machine to be offline, and if after 60s
 +
the machine is still online will notify that the shutdown action failed.
 +
Please note that containers without a Start/Shutdown order parameter will always
 +
start after those where the parameter is set, and this parameter only
 +
makes sense between the machines running locally on a host, and not
 +
cluster-wide.
 +
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.
 +
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
 
pct start 100
</pre>
+
Start a login session via getty
 
+
pct console 100
==Stop container==
+
Enter the LXC namespace and run a shell as root user
Stopping a container can be done in a similar way like starting a container.
+
pct enter 100
[[File:Stop_CT.png|200px|thumb|rigth|Stop Container]]
+
Display the configuration
<pre>
+
pct config 100
pct stop 100
+
Add a network interface called eth0, bridged to the host bridge vmbr0,
</pre>
+
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
==Backup container==
+
Reduce the memory of the container to 512MB
The backup can be done in three different modes: snapshot, suspend and stopped. This mode options have only an effect if the container is running.
+
pct set 100 -memory 512
[[File:Backup_CT.png|200px|thumb|rigth|Backup Container]]
+
Obtaining Debugging Logs
Snapshot mode: this feature depends on the filesystem and so it must support snapshots. If snapshot mode is chosen but it's not supported by the filesystem the backup will be done in suspend mode.  
+
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
Suspend mode: the container will be frozen during the time the backup is running. <b>NOTE: Container is not running untill backup is done!</b>
+
the container&#8217;s ID):
 
+
lxc-start -n ID -F -l DEBUG -o /tmp/lxc-ID.log
Stopped mode: the container will be turned off and restarted after backup.
+
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.
 +
Migration
 +
If you have a cluster, you can migrate your Containers with
 +
pct migrate &lt;vmid&gt; &lt;target&gt;
 +
This works as long as your Container is offline. If it has local volumes or
 +
mountpoints defined, the migration will copy the content over the network to
 +
the target host if there is the same storage defined.
 +
If you want to migrate online Containers, the only way is to use
 +
restart migration. This can be initiated with the -restart flag and the optional
 +
-timeout parameter.
 +
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
 +
Those configuration files are simple text files, and you can edit them
 +
using a normal text editor (vi, nano, &#8230;). 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.
 +
File Format
 +
Container configuration files use a simple colon separated key/value
 +
format. Each line has the following format:
 +
# this is a comment
 +
OPTION: value
 +
Blank lines in those files are ignored, and lines starting with a #
 +
character are treated as comments and are also ignored.
 +
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
 +
Those settings are directly passed 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
 +
arch: &lt;amd64 | arm64 | armhf | i386&gt; (default = amd64)
 +
OS architecture type.
 +
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: &lt;boolean&gt; (default = 1)
 +
Attach a console device (/dev/console) to the container.
 +
cores: &lt;integer&gt; (1 - 128)
 +
The number of cores assigned to the container. A container can use all available cores by default.
 +
cpulimit: &lt;number&gt; (0 - 128) (default = 0)
 +
Limit of CPU usage.
 +
If the computer has 2 CPUs, it has a total of 2 CPU time. Value 0 indicates no CPU limit.
 +
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.
 +
You can disable fair-scheduler configuration by setting this to 0.
 +
description: &lt;string&gt;
 +
Container description. Only used on the configuration web interface.
 +
features: [fuse=&lt;1|0&gt;] [,keyctl=&lt;1|0&gt;] [,mount=&lt;fstype;fstype;...&gt;] [,nesting=&lt;1|0&gt;]
 +
Allow containers access to advanced features.
 +
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.
 +
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.
 +
lock: &lt;backup | create | disk | fstrim | migrate | mounted | rollback | snapshot | snapshot-delete&gt;
 +
Lock/unlock the VM.
 +
memory: &lt;integer&gt; (16 - N) (default = 512)
 +
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;] [,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.
 +
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.
 +
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.
 +
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.
 +
onboot: &lt;boolean&gt; (default = 0)
 +
Specifies whether a VM will be started during system bootup.
 +
ostype: &lt;alpine | archlinux | centos | debian | 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.
 +
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.
 +
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.
 +
acl=&lt;boolean&gt;
 +
Explicitly enable or disable ACL support.
 +
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)
 +
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.
 +
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.
 +
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: &lt;integer&gt; (0 - N) (default = 512)
 +
Amount of SWAP for the VM in MB.
 +
template: &lt;boolean&gt; (default = 0)
 +
Enable/disable Template.
 +
tty: &lt;integer&gt; (0 - 6) (default = 2)
 +
Specify the number of tty available to the container
 +
unprivileged: &lt;boolean&gt; (default = 0)
 +
Makes the container run as unprivileged user. (Should not be modified manually.)
 +
unused[n]: &lt;string&gt;
 +
Reference to unused volumes. This is used internally, and should not be modified manually.
 +
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 &lt;CTID&gt;
 +
Only do that if you are sure the action which set the lock is
 +
no longer running.
 +
</pvehide>
 +
<!--PVE_IMPORT_END_MARKER-->
  
The command line tool backing up Linux container is vzdump.
 
For more information read vzdump manpage.
 
  
vzdump 100 -compress lzo -dumpdir /var/lib/vz/dump/ -mode snapshot -remove 0
 
  
==Restore container==
 
[[File:Restore CT.png|200px|thumb|rigth|Restore Container]]
 
It is easy and fast to restore a container.
 
  
On the GUI it is only possible to restore a container with the same VMID and if there is no VM with this VMID.
+
=== Security ===
 +
LXC Containers use an AppArmor profile to provide resource 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:
  
If you need to change the VMID or override a VM you can use the command line tool pct.
+
dmesg | grep apparmor
  
For more information read the man page of pct.
+
If you want to disable AppArmor for a container, you can add the stanza
pct restore 101 /var/lib/vz/dump/vzdump-lxc-100-2015_06_22-11_12_40.tar.lzo
 
  
=Migrate container from OpenVZ to Linux container=
+
lxc.aa_profile = unconfined
<b>NOTE:</b>At the moment you must do it manually later it will work with backup and restore.
 
Make a Backup (use gzip) of the OpenVZ container.
 
  
Then copy the backup file in /var/lib/vz/template/cache/
+
at the end of the configuration file ( located in /etc/pve/lxc/CTID.conf ) Note that this is not a recommended setup for production.
  
Now it is possible to create a new CT, using the backup as template. see create container. [[Linux Container#Create_container|Create_container]]
 
  
=References=
+
== Migrate container from OpenVZ to Linux container ==
[https://en.wikipedia.org/wiki/LXC Wikipedia Linux Container]
+
Follow this howto:
 +
* [[Convert OpenVZ to LXC]]
  
[https://linuxcontainers.org/ Linux Container]
+
== References ==
 +
* [https://en.wikipedia.org/wiki/LXC Wikipedia Linux Container]
 +
* [https://linuxcontainers.org/ Linux Container]
 +
* [https://github.com/lxc GIT Linux Container]
  
[https://github.com/lxc GIT Linux Container]
+
[[Category:Installation]][[Category:HOWTO]]
[[Category:Installation]][[Category:Technology]][[Category:HOWTO]]
 

Latest revision as of 11:23, 16 July 2019

Containers are a lightweight alternative to fully virtualized VMs. Instead of emulating a complete Operating System (OS), containers simply use the OS of the host they run on. This implies that all containers use the same kernel, and that they can access resources from the host directly.

This is great because containers do not waste CPU power nor memory due to kernel emulation. Container run-time costs are close to zero and usually negligible. But there are also some drawbacks you need to consider:

  • You can only run Linux based OS inside containers, i.e. it is not possible to run FreeBSD or MS Windows inside.

  • For security reasons, access to host resources needs to be restricted. This is done with AppArmor, SecComp filters and other kernel features. Be prepared that some syscalls are not allowed inside containers.

Proxmox VE uses LXC as underlying container technology. We consider LXC as low-level library, which provides countless options. It would be too difficult to use those tools directly. Instead, we provide a small wrapper called pct, the "Proxmox Container Toolkit".

The toolkit is tightly coupled with Proxmox VE. That means that it is aware of the cluster setup, and it can use the same network and storage resources as fully virtualized VMs. You can even use the Proxmox VE firewall, or manage containers using the HA framework.

Our primary goal is to offer an environment as one would get from a VM, but without the additional overhead. We call this "System Containers".

Note If you want to run micro-containers (with docker, rkt, …), it is best to run them inside a VM.

Technology Overview

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

  • Integrated into Proxmox VE graphical user interface (GUI)

  • Easy to use command line tool pct

  • Access via Proxmox VE REST API

  • lxcfs to provide containerized /proc file system

  • AppArmor/Seccomp to improve security

  • CRIU: for live migration (planned)

  • Runs on modern Linux kernels

  • Image based deployment (templates)

  • Use Proxmox VE storage library

  • Container setup from host (network, DNS, storage, …)

Security Considerations

Containers use the same kernel as the host, so there is a big attack surface for malicious users. You should consider this fact if you provide containers to totally untrusted people. In general, fully virtualized VMs provide better isolation.

The good news is that LXC uses many kernel security features like AppArmor, CGroups and PID and user namespaces, which makes containers usage quite secure.

Guest Operating System Configuration

We normally try to detect the operating system type inside the container, and then modify some files inside the container to make them work as expected. Here is a short list of things we do at container startup:

set /etc/hostname

to set the container name

modify /etc/hosts

to allow lookup of the local hostname

network setup

pass the complete network setup to the container

configure DNS

pass information about DNS servers

adapt the init system

for example, fix the number of spawned getty processes

set the root password

when creating a new container

rewrite ssh_host_keys

so that each container has unique keys

randomize crontab

so that cron does not start at the same time on all containers

Changes made by Proxmox VE are enclosed by comment markers:

# --- BEGIN PVE ---
<data>
# --- END PVE ---

Those markers will be inserted at a reasonable location in the file. If such a section already exists, it will be updated in place and will not be moved.

Modification of a file can be prevented by adding a .pve-ignore. file for it. For instance, if the file /etc/.pve-ignore.hosts exists then the /etc/hosts file will not be touched. This can be a simple empty file created via:

# touch /etc/.pve-ignore.hosts

Most modifications are OS dependent, so they differ between different distributions and versions. You can completely disable modifications by manually setting the ostype to unmanaged.

OS type detection is done by testing for certain files inside the container:

Ubuntu

inspect /etc/lsb-release (DISTRIB_ID=Ubuntu)

Debian

test /etc/debian_version

Fedora

test /etc/fedora-release

RedHat or CentOS

test /etc/redhat-release

ArchLinux

test /etc/arch-release

Alpine

test /etc/alpine-release

Gentoo

test /etc/gentoo-release

Note Container start fails if the configured ostype differs from the auto detected type.

Container Images

Container images, sometimes also referred to as “templates” or “appliances”, are tar archives which contain everything to run a container. You can think of it as a tidy container backup. Like most modern container toolkits, pct uses those images when you create a new container, for example:

pct create 999 local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz

Proxmox VE itself ships a set of basic templates for most common operating systems, and you can download them using the pveam (short for Proxmox VE Appliance Manager) command line utility. You can also download TurnKey Linux containers using that tool (or the graphical user interface).

Our image repositories contain a list of available images, and there is a cron job run each day to download that list. You can trigger that update manually with:

pveam update

After that you can view the list of available images using:

pveam available

You can restrict this large list by specifying the section you are interested in, for example basic system images:

List available system images
# pveam available --section system
system          archlinux-base_2015-24-29-1_x86_64.tar.gz
system          centos-7-default_20160205_amd64.tar.xz
system          debian-6.0-standard_6.0-7_amd64.tar.gz
system          debian-7.0-standard_7.0-3_amd64.tar.gz
system          debian-8.0-standard_8.0-1_amd64.tar.gz
system          ubuntu-12.04-standard_12.04-1_amd64.tar.gz
system          ubuntu-14.04-standard_14.04-1_amd64.tar.gz
system          ubuntu-15.04-standard_15.04-1_amd64.tar.gz
system          ubuntu-15.10-standard_15.10-1_amd64.tar.gz

Before you can use such a template, you need to download them into one of your storages. You can simply use storage local for that purpose. For clustered installations, it is preferred to use a shared storage so that all nodes can access those images.

pveam download local debian-8.0-standard_8.0-1_amd64.tar.gz

You are now ready to create containers using that image, and you can list all downloaded images on storage local with:

# pveam list local
local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz  190.20MB

The above command shows you the full Proxmox VE volume identifiers. They include the storage name, and most other Proxmox VE commands can use them. For example you can delete that image later with:

pveam remove local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz

Container Storage

Traditional containers use a very simple storage model, only allowing a single mount point, the root file system. This was further restricted to specific file system types like ext4 and nfs. Additional mounts are often done by user provided scripts. This turned out to be complex and error prone, so we try to avoid that now.

Our new LXC based container model is more flexible regarding storage. First, you can have more than a single mount point. This allows you to choose a suitable storage for each application. For example, you can use a relatively slow (and thus cheap) storage for the container root file system. Then you can use a second mount point to mount a very fast, distributed storage for your database application. See section Mount Points for further details.

The second big improvement is that you can use any storage type supported by the Proxmox VE storage library. That means that you can store your containers on local lvmthin or zfs, shared iSCSI storage, or even on distributed storage systems like ceph. It also enables us to use advanced storage features like snapshots and clones. vzdump can also use the snapshot feature to provide consistent container backups.

Last but not least, you can also mount local devices directly, or mount local directories using bind mounts. That way you can access local storage inside containers with zero overhead. Such bind mounts also provide an easy way to share data between different containers.

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. This only works on ext4 image based storage types and currently does not work with unprivileged containers.

Activating the quota option causes the following mount options to be used for a mount point: usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0

This allows quotas to be used like you would on any other system. You can initialize the /aquota.user and /aquota.group files by running

quotacheck -cmug /
quotaon /

and edit the quotas via the edquota command. Refer to the documentation of the distribution running inside the container for details.

Note You need to run the above commands for every mount point by passing the mount point’s path instead of just /.

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 Containers mount points

By default additional mount points besides the Root Disk mount point are not included in backups. You can reverse this default behavior by setting the Backup option on a mount point.

Replication of Containers mount points

By default additional mount points are replicated when the Root Disk is replicated. If you want the Proxmox VE storage replication mechanism to skip a mount point when starting a replication job, you can set the Skip replication option on that mount point.
As of Proxmox VE 5.0, replication requires a storage of type zfspool, so adding a mount point to a different type of storage when the container has replication configured requires to Skip replication for that mount point.

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.

Privileged Containers

Security is done by dropping capabilities, using mandatory access control (AppArmor), SecComp filters and namespaces. The LXC team considers this kind of container as unsafe, and they will not consider new container escape exploits to be security issues worthy of a CVE and quick fix. So you should use this kind of containers only inside a trusted environment, or when no untrusted task is running as root in the container.

Unprivileged Containers

This kind of containers use a new kernel feature called user namespaces. The root UID 0 inside the container is mapped to an unprivileged user outside the container. This means that most security issues (container escape, resource abuse, …) in those containers will affect a random unprivileged user, and so would be a generic kernel security bug rather than an LXC issue. The LXC team thinks unprivileged containers are safe by design.

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

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. You can view the assigned CPUs using the following command:

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

Containers use the host kernel directly, so all task inside a container are handled by the host CPU scheduler. Proxmox VE uses the Linux CFS (Completely Fair Scheduler) scheduler by default, which has additional bandwidth control options.

cpulimit:

You can use this option to further limit assigned CPU time. Please note that this is a floating point number, so it is perfectly valid to assign two cores to a container, but restrict overall CPU consumption to half a core.

cores: 2
cpulimit: 0.5
cpuunits:

This is a relative weight passed to the kernel scheduler. The larger the number is, the more CPU time this container gets. Number is relative to the weights of all the other running containers. The default is 1024. You can use this setting to prioritize some containers.

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, and you can configure up to 10 additional mount points. The corresponding options are called mp0 to mp9, and they can contain the following setting:

rootfs: [volume=]<volume> [,acl=<1|0>] [,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.

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 basically three types of mount points: storage backed mount points, bind mounts and device mounts.

Typical container rootfs configuration
rootfs: thin1:base-100-disk-1,size=8G

Storage Backed Mount Points

Storage backed mount points are managed by the Proxmox VE storage subsystem and come in three different flavors:

  • Image based: these are raw images containing a single ext4 formatted file system.

  • ZFS subvolumes: these are technically bind mounts, but with managed storage, and thus allow resizing and snapshotting.

  • Directories: passing size=0 triggers a special case where instead of a raw image a directory is created.

Note The special option syntax STORAGE_ID:SIZE_IN_GB for storage backed mount point volumes will automatically allocate a volume of the specified size on the specified storage. E.g., calling pct set 100 -mp0 thin1:10,mp=/path/in/container will allocate a 10GB volume on the storage thin1 and replace the volume ID place holder 10 with the allocated volume ID.

Bind Mount Points

Bind mounts allow you to access arbitrary directories from your Proxmox VE host inside a container. Some potential use cases are:

  • Accessing your home directory in the guest

  • Accessing an USB device directory in the guest

  • Accessing an NFS mount from the host in the guest

Bind mounts are considered to not be managed by the storage subsystem, so you cannot make snapshots or deal with quotas from inside the container. With unprivileged containers you might run into permission problems caused by the user mapping and cannot use ACLs.

Note The contents of bind mount points are not backed up when using vzdump.
Warning For security reasons, bind mounts should only be established using source directories especially reserved for this purpose, e.g., a directory hierarchy under /mnt/bindmounts. Never bind mount system directories like /, /var or /etc into a container - this poses a great security risk.
Note The bind mount source path must not contain any symlinks.

For example, to make the directory /mnt/bindmounts/shared accessible in the container with ID 100 under the path /shared, use a configuration line like mp0: /mnt/bindmounts/shared,mp=/shared in /etc/pve/lxc/100.conf. Alternatively, use pct set 100 -mp0 /mnt/bindmounts/shared,mp=/shared to achieve the same result.

Device Mount Points

Device mount points allow to mount block devices of the host directly into the container. Similar to bind mounts, device mounts are not managed by Proxmox VE’s storage subsystem, but the quota and acl options will be honored.

Note Device mount points should only be used under special circumstances. In most cases a storage backed mount point offers the same performance and a lot more features.
Note The contents of device mount points are not backed up when using vzdump.

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)>] [,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.

mtu=<integer> (64 - N)

Maximum transfer unit of the interface. (lxc.network.mtu)

name=<string>

Name of the network device as seen from inside the container. (lxc.network.name)

rate=<mbps>

Apply rate limiting to the interface

tag=<integer> (1 - 4094)

VLAN tag for this interface.

trunks=<vlanid[;vlanid...]>

VLAN ids to pass through the interface

type=<veth>

Network interface type.

Automatic Start and Shutdown of Containers

After creating your containers, you probably want them to start automatically when the host system boots. For this you need to select the option Start at boot from the Options Tab of your container in the web interface, or set it with the following command:

pct set <ctid> -onboot 1
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. E.g. set it to 1 if you want the CT to be the first to be started. (We use the reverse startup order for shutdown, so a container with a start order of 1 would be the last to be shut down)

  • Startup delay: Defines the interval between this container start and subsequent containers starts . E.g. set it to 240 if you want to wait 240 seconds before starting other containers.

  • Shutdown timeout: Defines the duration in seconds Proxmox VE should wait for the container to be offline after issuing a shutdown command. By default this value is set to 60, which means that Proxmox VE will issue a shutdown request, wait 60s for the machine to be offline, and if after 60s the machine is still online will notify that the shutdown action failed.

Please note that containers without a Start/Shutdown order parameter will always start after those where the parameter is set, and this parameter only makes sense between the machines running locally on a host, and not cluster-wide.

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.

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 storage provided with the storage parameter, or default local storage if unset)

  3. Extract files from backup archive

  4. Add bind and device mount points to restored configuration (limited to root user)

Note Since bind and device mount points are never backed up, no files are restored in the last step, but only the configuration options. The assumption is that such mount points are either backed up with another mechanism (e.g., NFS space that is bind mounted into many containers), or not intended to be backed up at all.

This simple mode is also used by the container restore operations in the web interface.

“Advanced” Restore Mode

By setting the rootfs parameter (and optionally, any combination of mpX parameters), the pct restore command is automatically switched into an advanced mode. This advanced mode completely ignores the rootfs and mpX configuration options contained in the backup archive, and instead only uses the options explicitly provided as parameters.

This mode allows flexible configuration of mount point settings at restore time, for example:

  • Set target storages, volume sizes and other options for each mount point individually

  • Redistribute backed up files according to new mount point scheme

  • Restore to device and/or bind mount points (limited to root user)

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, …). 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’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’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.

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 <vmid> <target>

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

If you want to migrate online Containers, the only way is to use restart migration. This can be initiated with the -restart flag and the optional -timeout parameter.

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

Those configuration files are simple text files, and you can edit them using a normal text editor (vi, nano, …). This is sometimes useful to do small corrections, but keep in mind that you need to restart the 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.

File Format

Container configuration files use a simple colon separated key/value format. Each line has the following format:

# this is a comment
OPTION: value

Blank lines in those files are ignored, and lines starting with a # character are treated as comments and are also ignored.

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

Those settings are directly passed 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> (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 - 128)

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

cpulimit: <number> (0 - 128) (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 = 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.

Note You can disable fair-scheduler configuration by setting this to 0.
description: <string>

Container description. Only used on the configuration web interface.

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

Allow containers access to advanced features.

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.

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 | disk | fstrim | migrate | mounted | rollback | snapshot | snapshot-delete>

Lock/unlock the VM.

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

Amount of RAM for the VM 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.

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)>] [,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.

mtu=<integer> (64 - N)

Maximum transfer unit of the interface. (lxc.network.mtu)

name=<string>

Name of the network device as seen from inside the container. (lxc.network.name)

rate=<mbps>

Apply rate limiting to the interface

tag=<integer> (1 - 4094)

VLAN tag for this interface.

trunks=<vlanid[;vlanid...]>

VLAN ids to pass through the interface

type=<veth>

Network interface type.

onboot: <boolean> (default = 0)

Specifies whether a VM will be started during system bootup.

ostype: <alpine | archlinux | centos | debian | fedora | gentoo | 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 VM in MB.

template: <boolean> (default = 0)

Enable/disable Template.

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]: <string>

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

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 that if you are sure the action which set the lock is no longer running.



Security

LXC Containers use an AppArmor profile to provide resource 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.


Migrate container from OpenVZ to Linux container

Follow this howto:

References