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 containers.It is not possible to run
- other Operating Systems like, for example, FreeBSD or Microsoft Windows
+* 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.
- Containers run in their own separate namespaces. Additionally some syscalls
- are not allowed within containers.
+ Therefore, containers run in their own separate namespaces. Additionally some
+ syscalls (user space requests to the Linux kernel) are not allowed within containers.
-{pve} uses https://linuxcontainers.org/[Linux Containers (LXC)] as underlying
+{pve} uses https://linuxcontainers.org/lxc/introduction/[Linux Containers (LXC)] as its underlying
container technology. The ``Proxmox Container Toolkit'' (`pct`) simplifies the
-usage and management of LXC containers.
+usage and management of LXC, by providing an interface that abstracts
+complex tasks.
Containers are tightly integrated with {pve}. 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 {pve} 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''.
+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 micro-containers, for example, 'Docker' or 'rkt', it
-is best to run them inside a VM.
+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
* Integrated into {pve} graphical web user interface (GUI)
-* Easy to use command line tool `pct`
+* Easy to use command-line tool `pct`
* Access via {pve} REST API
* Modern Linux kernels
-* Image based deployment (templates)
+* Image based deployment (xref:pct_supported_distributions[templates])
* Uses {pve} xref:chapter_storage[storage library]
* Container setup from host (network, DNS, storage, etc.)
-Security Considerations
+
+[[pct_supported_distributions]]
+Supported Distributions
-----------------------
-Containers use the kernel of the host system. This creates a big attack
-surface for malicious users. This should be considered if containers
-are provided to untrustworthy people. In general, full
-virtual machines provide better isolation.
+List of officially supported distributions can be found below.
-However, LXC uses many security features like AppArmor, CGroups and kernel
-namespaces to reduce the attack surface.
+Templates for the following distributions are available through our
+repositories. You can use xref:pct_container_images[pveam] tool or the
+Graphical User Interface to download them.
-AppArmor profiles are used to restrict access to possibly dangerous actions.
-Some system calls, i.e. `mount`, are prohibited from execution.
+Alpine Linux
+~~~~~~~~~~~~
-To trace AppArmor activity, use:
+[quote, 'https://alpinelinux.org']
+____
+Alpine Linux is a security-oriented, lightweight Linux distribution based on
+musl libc and busybox.
+____
-----
-# dmesg | grep apparmor
-----
+For currently supported releases see:
-Guest Operating System Configuration
-------------------------------------
+https://alpinelinux.org/releases/
-{pve} tries to detect the Linux distribution in the container, and modifies some
-files. Here is a short list of things done at container startup:
+Arch Linux
+~~~~~~~~~~
-set /etc/hostname:: to set the container name
+[quote, 'https://archlinux.org/']
+____
+Arch Linux, a lightweight and flexible Linux® distribution that tries to Keep It Simple.
+____
-modify /etc/hosts:: to allow lookup of the local hostname
+Arch Linux is using a rolling-release model, see its wiki for more details:
-network setup:: pass the complete network setup to the container
+https://wiki.archlinux.org/title/Arch_Linux
-configure DNS:: pass information about DNS servers
+CentOS, Almalinux, Rocky Linux
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-adapt the init system:: for example, fix the number of spawned getty processes
+CentOS / CentOS Stream
+^^^^^^^^^^^^^^^^^^^^^^
-set the root password:: when creating a new container
+[quote, 'https://centos.org']
+____
+The CentOS Linux distribution is a stable, predictable, manageable and
+reproducible platform derived from the sources of Red Hat Enterprise Linux
+(RHEL)
+____
-rewrite ssh_host_keys:: so that each container has unique keys
+For currently supported releases see:
-randomize crontab:: so that cron does not start at the same time on all containers
+https://en.wikipedia.org/wiki/CentOS#End-of-support_schedule
-Changes made by {PVE} are enclosed by comment markers:
+Almalinux
+^^^^^^^^^
-----
-# --- BEGIN PVE ---
-<data>
-# --- END PVE ---
-----
+[quote, 'https://almalinux.org']
+____
+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.
+____
-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:
+For currently supported releases see:
-----
-# touch /etc/.pve-ignore.hosts
-----
+https://en.wikipedia.org/wiki/AlmaLinux#Releases
-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`.
+Rocky Linux
+^^^^^^^^^^^
-OS type detection is done by testing for certain files inside the
-container:
+[quote, 'https://rockylinux.org']
+____
+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.
+____
-Ubuntu:: inspect /etc/lsb-release (`DISTRIB_ID=Ubuntu`)
+For currently supported releases see:
-Debian:: test /etc/debian_version
+https://en.wikipedia.org/wiki/Rocky_Linux#Releases
-Fedora:: test /etc/fedora-release
+Debian
+~~~~~~
-RedHat or CentOS:: test /etc/redhat-release
+[quote, 'https://www.debian.org/intro/index#software']
+____
+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.
+____
-ArchLinux:: test /etc/arch-release
+For currently supported releases see:
-Alpine:: test /etc/alpine-release
+https://www.debian.org/releases/stable/releasenotes
-Gentoo:: test /etc/gentoo-release
+Devuan
+~~~~~~
-NOTE: Container start fails if the configured `ostype` differs from the auto
-detected type.
+[quote, 'https://www.devuan.org']
+____
+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.
+____
+
+For currently supported releases see:
+
+https://www.devuan.org/os/releases
+
+Fedora
+~~~~~~
+
+[quote, 'https://getfedora.org']
+____
+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.
+____
+
+For currently supported releases see:
+https://fedoraproject.org/wiki/Releases
+
+Gentoo
+~~~~~~
+
+[quote, 'https://www.gentoo.org']
+____
+a highly flexible, source-based Linux distribution.
+____
+
+Gentoo is using a rolling-release model.
+
+OpenSUSE
+~~~~~~~~
+
+[quote, 'https://www.opensuse.org']
+____
+The makers' choice for sysadmins, developers and desktop users.
+____
+
+For currently supported releases see:
+
+https://get.opensuse.org/leap/
+
+Ubuntu
+~~~~~~
+
+[quote, 'https://ubuntu.com/']
+____
+Ubuntu is the modern, open source operating system on Linux for the enterprise
+server, desktop, cloud, and IoT.
+____
+
+For currently supported releases see:
+
+https://wiki.ubuntu.com/Releases
[[pct_container_images]]
Container Images
----------------
Container images, sometimes also referred to as ``templates'' or
-``appliances'', are `tar` archives which contain everything to run a
-container. `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
-----
+``appliances'', are `tar` archives which contain everything to run a container.
-{pve} 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 {pve} Appliance Manager) command line utility.
-Additionally, https://www.turnkeylinux.org/[TurnKey Linux]
-container templates are also available to download.
+{pve} itself provides a variety of basic templates for the
+xref:pct_supported_distributions[most common Linux distributions]. They can be
+downloaded using the GUI or the `pveam` (short for {pve} Appliance Manager)
+command-line utility. Additionally, https://www.turnkeylinux.org/[TurnKey
+Linux] container templates are also available to download.
-The list of available templates is updated daily via cron. To trigger it manually:
+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
.List available system images
----
# pveam available --section system
-system alpine-3.10-default_20190626_amd64.tar.xz
-system alpine-3.9-default_20190224_amd64.tar.xz
-system archlinux-base_20190924-1_amd64.tar.gz
-system centos-6-default_20191016_amd64.tar.xz
+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_20191016_amd64.tar.xz
-system debian-10.0-standard_10.0-1_amd64.tar.gz
-system debian-8.0-standard_8.11-1_amd64.tar.gz
+system centos-8-default_20201210_amd64.tar.xz
system debian-9.0-standard_9.7-1_amd64.tar.gz
-system fedora-30-default_20190718_amd64.tar.xz
-system fedora-31-default_20191029_amd64.tar.xz
-system gentoo-current-default_20190718_amd64.tar.xz
-system opensuse-15.0-default_20180907_amd64.tar.xz
-system opensuse-15.1-default_20190719_amd64.tar.xz
+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-19.04-standard_19.04-1_amd64.tar.gz
-system ubuntu-19.10-standard_19.10-1_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. 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.
+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:
+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
----
-The above command shows you the full {pve} volume identifiers. They include
-the storage name, and most other {pve} 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
-----
-
-[[pct_container_storage]]
-Container Storage
------------------
-
-The {pve} 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 <<pct_mount_points, Mount Points>> for further details.
-
-Any storage type supported by the {pve} 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 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 /
-----
-
-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 **A**ccess **C**ontrol **L**ists 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
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+TIP: You can also use the {pve} web interface GUI to download, list and delete
+container templates.
-To include a mount point in backups, enable the `backup` option for it in the
-container configuration. For an existing mount point `mp0`
+`pct` uses them to create a new container, for example:
----
-mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G
+# pct create 999 local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz
----
-add `backup=1` to enable it.
+The above command shows you the full {pve} volume identifiers. They include the
+storage name, and most other {pve} commands can use them. For example you can
+delete that image later with:
----
-mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G,backup=1
+# pveam remove local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz
----
-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 {pve} storage replication mechanism to skip a mount
-point, you can set the *Skip replication* option for that mount point. +
-As of {pve} 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.
[[pct_settings]]
Container 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 {pve} installation used to identify your container
+* the *CT ID*: a unique number in this {pve} 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.
+ 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
+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.
+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), 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. That's why privileged
-containers should only be used in trusted environments.
-
-WARNING: 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
-----
-
-Please note that this is not recommended for production use.
-
+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.
[[pct_cpu]]
You can restrict the number of visible CPUs inside the container using the
`cores` option. This is implemented using the Linux 'cpuset' cgroup
-(**c**ontrol *group*). A special task inside `pvestatd` tries to distribute
-running containers among available CPUs. To view the assigned CPUs run
-the following command:
+(**c**ontrol *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
[horizontal]
-`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.
+`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
+`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.
[horizontal]
-`memory`: :: Limit overall memory usage. This corresponds
-to the `memory.limit_in_bytes` cgroup setting.
+`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`).
+`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`).
[[pct_mount_points]]
[thumbnail="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:
+configure up to 256 additional mount points. The corresponding options are
+called `mp0` to `mp255`. They can contain the following settings:
include::pct-mountpoint-opts.adoc[]
-Currently there are three types of mount points: storage backed
-mount points, bind mounts, and device mounts.
+Currently there are three types of mount points: storage backed mount points,
+bind mounts, and device mounts.
.Typical container `rootfs` configuration
----
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.
+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
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.
+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.
+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
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`.
+NOTE: The contents of device mount points are not backed up when using
+`vzdump`.
[[pct_container_network]]
[thumbnail="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:
+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:
include::pct-network-opts.adoc[]
// use the screenshot from qemu - its the same
[thumbnail="screenshot/gui-qemu-edit-start-order.png"]
-If you want to fine tune the boot order of your containers, you can use the following
-parameters:
+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.
+* *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 {pve} should wait
-for the container to be offline after issuing a shutdown command.
-By default this value is set to 60, which means that {pve} 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.
+ for the container to be offline after issuing a shutdown command.
+ By default this value is set to 60, which means that {pve} 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
+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
+xref:first_guest_boot_delay[Proxmox VE Node Management].
+
+
Hookscripts
~~~~~~~~~~~
# 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
+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.
+
+
+[[pct_cgroup]]
+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,
+https://www.kernel.org/doc/html/v5.11/admin-guide/cgroup-v1/index.html[legacy]
+and
+https://www.kernel.org/doc/html/v5.11/admin-guide/cgroup-v2.html['cgroupv2'].
+
+Since {pve} 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
+https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html[kernel
+parameter documentation] for details.)
+
+[[pct_cgroup_compat]]
+CGroup Version Compatibility
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The main difference between pure 'cgroupv2' and the old hybrid environments
+regarding {pve} 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' footnote:[this includes all newest major versions of container
+templates shipped by {pve}], as do containers not using 'systemd' as init
+system footnote:[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 {pve} 9.0, the legacy
+ controller will not be supported anymore.
+====
+
+[[pct_cgroup_change_version]]
+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 xref:sysboot_edit_kernel_cmdline[this section] on editing the kernel boot
+command line on where to add the parameter.
+
+// TODO: seccomp a bit more.
+// TODO: pve-lxc-syscalld
+
+
+Guest Operating System Configuration
+------------------------------------
+
+{pve} 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 {PVE} 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. {pve} first checks the `/etc/os-release` file
+footnote:[/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.
+
+
+[[pct_container_storage]]
+Container Storage
+-----------------
+
+The {pve} 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 <<pct_mount_points, Mount Points>> for further
+details.
+
+Any storage type supported by the {pve} 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 **A**ccess **C**ontrol **L**ists 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 {pve} storage replication mechanism to skip a mount
+point, you can set the *Skip replication* option for that mount point.
+As of {pve} 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.
+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).
+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.
``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:
+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)
+. 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)
+. 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
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.
+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:
+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
+ 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
+The ``Proxmox Container Toolkit'' (`pct`) is the command-line tool to manage
{pve} 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
CLI Usage Examples
~~~~~~~~~~~~~~~~~~
-Create a container based on a Debian template (provided you have
-already downloaded the template via the web interface)
+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
# pct config 100
----
-Add a network interface called `eth0`, bridged to the host bridge `vmbr0`,
-set the address and gateway, while it's running
+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
# 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 running `lxc-start` (replace `ID` with
-the container's ID):
+helpful to collect debugging output by passing the `--debug` flag (replace `CTID` with
+the container's CTID):
----
-# lxc-start -n ID -F -l DEBUG -o /tmp/lxc-ID.log
+# pct start CTID --debug
----
-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.
+Alternatively, you can use the following `lxc-start` command, which will save
+the debug log to the file specified by the `-o` output option:
-The collected debug log is written to `/tmp/lxc-ID.log`.
+----
+# 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
mount points defined, the migration will copy the content over the network to
the target host if the same storage is defined there.
-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.
+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 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.
+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.
[[pct_configuration]]
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.
+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.
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 (`vi`, `nano`, etc). This is sometimes
-useful to do small corrections, but keep in mind that you need to
-restart the container to apply such changes.
+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.
+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.
+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:
+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.
+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:
+It is possible to add low-level, LXC style configuration directly, for example:
----
lxc.init_cmd: /sbin/my_own_init
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:
+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
----
...
----
-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).
+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).
[[pct_options]]
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).
+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.
+CAUTION: Only do this if you are sure the action which set the lock is no
+longer running.
ifdef::manvolnum[]
include::pve-copyright.adoc[]
endif::manvolnum[]
-
-
-
-
-
-
-
projects / pve-docs.git / blobdiff