10 pct - Tool to manage Linux Containers (LXC) on Proxmox VE
16 include::pct.1-synopsis.adoc[]
23 Proxmox Container Toolkit
24 =========================
28 :title: Linux Container
31 Containers are a lightweight alternative to fully virtualized machines (VMs).
32 They use the kernel of the host system that they run on, instead of emulating a
33 full operating system (OS). This means that containers can access resources on
34 the host system directly.
36 The runtime costs for containers is low, usually negligible. However, there are
37 some drawbacks that need be considered:
39 * Only Linux distributions can be run in Proxmox Containers. It is not possible to run
40 other operating systems like, for example, FreeBSD or Microsoft Windows
43 * For security reasons, access to host resources needs to be restricted.
44 Therefore, containers run in their own separate namespaces. Additionally some
45 syscalls (user space requests to the Linux kernel) are not allowed within containers.
47 {pve} uses https://linuxcontainers.org/lxc/introduction/[Linux Containers (LXC)] as its underlying
48 container technology. The ``Proxmox Container Toolkit'' (`pct`) simplifies the
49 usage and management of LXC, by providing an interface that abstracts
52 Containers are tightly integrated with {pve}. This means that they are aware of
53 the cluster setup, and they can use the same network and storage resources as
54 virtual machines. You can also use the {pve} firewall, or manage containers
55 using the HA framework.
57 Our primary goal is to offer an environment that provides the benefits of using a
58 VM, but without the additional overhead. This means that Proxmox Containers can
59 be categorized as ``System Containers'', rather than ``Application Containers''.
61 NOTE: If you want to run application containers, for example, 'Docker' images, it
62 is recommended that you run them inside a Proxmox QEMU VM. This will give you
63 all the advantages of application containerization, while also providing the
64 benefits that VMs offer, such as strong isolation from the host and the ability
65 to live-migrate, which otherwise isn't possible with containers.
71 * LXC (https://linuxcontainers.org/)
73 * Integrated into {pve} graphical web user interface (GUI)
75 * Easy to use command-line tool `pct`
77 * Access via {pve} REST API
79 * 'lxcfs' to provide containerized /proc file system
81 * Control groups ('cgroups') for resource isolation and limitation
83 * 'AppArmor' and 'seccomp' to improve security
85 * Modern Linux kernels
87 * Image based deployment (xref:pct_supported_distributions[templates])
89 * Uses {pve} xref:chapter_storage[storage library]
91 * Container setup from host (network, DNS, storage, etc.)
94 [[pct_supported_distributions]]
95 Supported Distributions
96 -----------------------
98 List of officially supported distributions can be found below.
100 Templates for the following distributions are available through our
101 repositories. You can use xref:pct_container_images[pveam] tool or the
102 Graphical User Interface to download them.
107 [quote, 'https://alpinelinux.org']
109 Alpine Linux is a security-oriented, lightweight Linux distribution based on
110 musl libc and busybox.
113 For currently supported releases see:
115 https://alpinelinux.org/releases/
120 [quote, 'https://archlinux.org/']
122 Arch Linux, a lightweight and flexible Linux® distribution that tries to Keep It Simple.
125 Arch Linux is using a rolling-release model, see its wiki for more details:
127 https://wiki.archlinux.org/title/Arch_Linux
129 CentOS, Almalinux, Rocky Linux
130 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
132 CentOS / CentOS Stream
133 ^^^^^^^^^^^^^^^^^^^^^^
135 [quote, 'https://centos.org']
137 The CentOS Linux distribution is a stable, predictable, manageable and
138 reproducible platform derived from the sources of Red Hat Enterprise Linux
142 For currently supported releases see:
144 https://en.wikipedia.org/wiki/CentOS#End-of-support_schedule
149 [quote, 'https://almalinux.org']
151 An Open Source, community owned and governed, forever-free enterprise Linux
152 distribution, focused on long-term stability, providing a robust
153 production-grade platform. AlmaLinux OS is 1:1 binary compatible with RHEL® and
158 For currently supported releases see:
160 https://en.wikipedia.org/wiki/AlmaLinux#Releases
165 [quote, 'https://rockylinux.org']
167 Rocky Linux is a community enterprise operating system designed to be 100%
168 bug-for-bug compatible with America's top enterprise Linux distribution now
169 that its downstream partner has shifted direction.
172 For currently supported releases see:
174 https://en.wikipedia.org/wiki/Rocky_Linux#Releases
179 [quote, 'https://www.debian.org/intro/index#software']
181 Debian is a free operating system, developed and maintained by the Debian
182 project. A free Linux distribution with thousands of applications to meet our
186 For currently supported releases see:
188 https://www.debian.org/releases/stable/releasenotes
193 [quote, 'https://www.devuan.org']
195 Devuan GNU+Linux is a fork of Debian without systemd that allows users to
196 reclaim control over their system by avoiding unnecessary entanglements and
197 ensuring Init Freedom.
200 For currently supported releases see:
202 https://www.devuan.org/os/releases
207 [quote, 'https://getfedora.org']
209 Fedora creates an innovative, free, and open source platform for hardware,
210 clouds, and containers that enables software developers and community members
211 to build tailored solutions for their users.
214 For currently supported releases see:
216 https://fedoraproject.org/wiki/Releases
221 [quote, 'https://www.gentoo.org']
223 a highly flexible, source-based Linux distribution.
226 Gentoo is using a rolling-release model.
231 [quote, 'https://www.opensuse.org']
233 The makers' choice for sysadmins, developers and desktop users.
236 For currently supported releases see:
238 https://get.opensuse.org/leap/
243 [quote, 'https://ubuntu.com/']
245 Ubuntu is the modern, open source operating system on Linux for the enterprise
246 server, desktop, cloud, and IoT.
249 For currently supported releases see:
251 https://wiki.ubuntu.com/Releases
253 [[pct_container_images]]
257 Container images, sometimes also referred to as ``templates'' or
258 ``appliances'', are `tar` archives which contain everything to run a container.
260 {pve} itself provides a variety of basic templates for the
261 xref:pct_supported_distributions[most common Linux distributions]. They can be
262 downloaded using the GUI or the `pveam` (short for {pve} Appliance Manager)
263 command-line utility. Additionally, https://www.turnkeylinux.org/[TurnKey
264 Linux] container templates are also available to download.
266 The list of available templates is updated daily through the 'pve-daily-update'
267 timer. You can also trigger an update manually by executing:
273 To view the list of available images run:
279 You can restrict this large list by specifying the `section` you are
280 interested in, for example basic `system` images:
282 .List available system images
284 # pveam available --section system
285 system alpine-3.12-default_20200823_amd64.tar.xz
286 system alpine-3.13-default_20210419_amd64.tar.xz
287 system alpine-3.14-default_20210623_amd64.tar.xz
288 system archlinux-base_20210420-1_amd64.tar.gz
289 system centos-7-default_20190926_amd64.tar.xz
290 system centos-8-default_20201210_amd64.tar.xz
291 system debian-9.0-standard_9.7-1_amd64.tar.gz
292 system debian-10-standard_10.7-1_amd64.tar.gz
293 system devuan-3.0-standard_3.0_amd64.tar.gz
294 system fedora-33-default_20201115_amd64.tar.xz
295 system fedora-34-default_20210427_amd64.tar.xz
296 system gentoo-current-default_20200310_amd64.tar.xz
297 system opensuse-15.2-default_20200824_amd64.tar.xz
298 system ubuntu-16.04-standard_16.04.5-1_amd64.tar.gz
299 system ubuntu-18.04-standard_18.04.1-1_amd64.tar.gz
300 system ubuntu-20.04-standard_20.04-1_amd64.tar.gz
301 system ubuntu-20.10-standard_20.10-1_amd64.tar.gz
302 system ubuntu-21.04-standard_21.04-1_amd64.tar.gz
305 Before you can use such a template, you need to download them into one of your
306 storages. If you're unsure to which one, you can simply use the `local` named
307 storage for that purpose. For clustered installations, it is preferred to use a
308 shared storage so that all nodes can access those images.
311 # pveam download local debian-10.0-standard_10.0-1_amd64.tar.gz
314 You are now ready to create containers using that image, and you can list all
315 downloaded images on storage `local` with:
319 local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz 219.95MB
322 TIP: You can also use the {pve} web interface GUI to download, list and delete
325 `pct` uses them to create a new container, for example:
328 # pct create 999 local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz
331 The above command shows you the full {pve} volume identifiers. They include the
332 storage name, and most other {pve} commands can use them. For example you can
333 delete that image later with:
336 # pveam remove local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz
348 [thumbnail="screenshot/gui-create-ct-general.png"]
350 General settings of a container include
352 * the *Node* : the physical server on which the container will run
353 * the *CT ID*: a unique number in this {pve} installation used to identify your
355 * *Hostname*: the hostname of the container
356 * *Resource Pool*: a logical group of containers and VMs
357 * *Password*: the root password of the container
358 * *SSH Public Key*: a public key for connecting to the root account over SSH
359 * *Unprivileged container*: this option allows to choose at creation time
360 if you want to create a privileged or unprivileged container.
362 Unprivileged Containers
363 ^^^^^^^^^^^^^^^^^^^^^^^
365 Unprivileged containers use a new kernel feature called user namespaces.
366 The root UID 0 inside the container is mapped to an unprivileged user outside
367 the container. This means that most security issues (container escape, resource
368 abuse, etc.) in these containers will affect a random unprivileged user, and
369 would be a generic kernel security bug rather than an LXC issue. The LXC team
370 thinks unprivileged containers are safe by design.
372 This is the default option when creating a new container.
374 NOTE: If the container uses systemd as an init system, please be aware the
375 systemd version running inside the container should be equal to or greater than
379 Privileged Containers
380 ^^^^^^^^^^^^^^^^^^^^^
382 Security in containers is achieved by using mandatory access control 'AppArmor'
383 restrictions, 'seccomp' filters and Linux kernel namespaces. The LXC team
384 considers this kind of container as unsafe, and they will not consider new
385 container escape exploits to be security issues worthy of a CVE and quick fix.
386 That's why privileged containers should only be used in trusted environments.
393 [thumbnail="screenshot/gui-create-ct-cpu.png"]
395 You can restrict the number of visible CPUs inside the container using the
396 `cores` option. This is implemented using the Linux 'cpuset' cgroup
397 (**c**ontrol *group*).
398 A special task inside `pvestatd` tries to distribute running containers among
399 available CPUs periodically.
400 To view the assigned CPUs run the following command:
404 ---------------------
408 ---------------------
411 Containers use the host kernel directly. All tasks inside a container are
412 handled by the host CPU scheduler. {pve} uses the Linux 'CFS' (**C**ompletely
413 **F**air **S**cheduler) scheduler by default, which has additional bandwidth
418 `cpulimit`: :: You can use this option to further limit assigned CPU time.
419 Please note that this is a floating point number, so it is perfectly valid to
420 assign two cores to a container, but restrict overall CPU consumption to half a
428 `cpuunits`: :: This is a relative weight passed to the kernel scheduler. The
429 larger the number is, the more CPU time this container gets. Number is relative
430 to the weights of all the other running containers. The default is `100` (or
431 `1024` if the host uses legacy cgroup v1). You can use this setting to
432 prioritize some containers.
439 [thumbnail="screenshot/gui-create-ct-memory.png"]
441 Container memory is controlled using the cgroup memory controller.
445 `memory`: :: Limit overall memory usage. This corresponds to the
446 `memory.limit_in_bytes` cgroup setting.
448 `swap`: :: Allows the container to use additional swap memory from the host
449 swap space. This corresponds to the `memory.memsw.limit_in_bytes` cgroup
450 setting, which is set to the sum of both value (`memory + swap`).
457 [thumbnail="screenshot/gui-create-ct-root-disk.png"]
459 The root mount point is configured with the `rootfs` property. You can
460 configure up to 256 additional mount points. The corresponding options are
461 called `mp0` to `mp255`. They can contain the following settings:
463 include::pct-mountpoint-opts.adoc[]
465 Currently there are three types of mount points: storage backed mount points,
466 bind mounts, and device mounts.
468 .Typical container `rootfs` configuration
470 rootfs: thin1:base-100-disk-1,size=8G
474 Storage Backed Mount Points
475 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
477 Storage backed mount points are managed by the {pve} storage subsystem and come
478 in three different flavors:
480 - Image based: these are raw images containing a single ext4 formatted file
482 - ZFS subvolumes: these are technically bind mounts, but with managed storage,
483 and thus allow resizing and snapshotting.
484 - Directories: passing `size=0` triggers a special case where instead of a raw
485 image a directory is created.
487 NOTE: The special option syntax `STORAGE_ID:SIZE_IN_GB` for storage backed
488 mount point volumes will automatically allocate a volume of the specified size
489 on the specified storage. For example, calling
492 pct set 100 -mp0 thin1:10,mp=/path/in/container
495 will allocate a 10GB volume on the storage `thin1` and replace the volume ID
496 place holder `10` with the allocated volume ID, and setup the moutpoint in the
497 container at `/path/in/container`
503 Bind mounts allow you to access arbitrary directories from your Proxmox VE host
504 inside a container. Some potential use cases are:
506 - Accessing your home directory in the guest
507 - Accessing an USB device directory in the guest
508 - Accessing an NFS mount from the host in the guest
510 Bind mounts are considered to not be managed by the storage subsystem, so you
511 cannot make snapshots or deal with quotas from inside the container. With
512 unprivileged containers you might run into permission problems caused by the
513 user mapping and cannot use ACLs.
515 NOTE: The contents of bind mount points are not backed up when using `vzdump`.
517 WARNING: For security reasons, bind mounts should only be established using
518 source directories especially reserved for this purpose, e.g., a directory
519 hierarchy under `/mnt/bindmounts`. Never bind mount system directories like
520 `/`, `/var` or `/etc` into a container - this poses a great security risk.
522 NOTE: The bind mount source path must not contain any symlinks.
524 For example, to make the directory `/mnt/bindmounts/shared` accessible in the
525 container with ID `100` under the path `/shared`, add a configuration line such as:
528 mp0: /mnt/bindmounts/shared,mp=/shared
531 into `/etc/pve/lxc/100.conf`.
533 Or alternatively use the `pct` tool:
536 pct set 100 -mp0 /mnt/bindmounts/shared,mp=/shared
539 to achieve the same result.
545 Device mount points allow to mount block devices of the host directly into the
546 container. Similar to bind mounts, device mounts are not managed by {PVE}'s
547 storage subsystem, but the `quota` and `acl` options will be honored.
549 NOTE: Device mount points should only be used under special circumstances. In
550 most cases a storage backed mount point offers the same performance and a lot
553 NOTE: The contents of device mount points are not backed up when using
557 [[pct_container_network]]
561 [thumbnail="screenshot/gui-create-ct-network.png"]
563 You can configure up to 10 network interfaces for a single container.
564 The corresponding options are called `net0` to `net9`, and they can contain the
567 include::pct-network-opts.adoc[]
570 [[pct_startup_and_shutdown]]
571 Automatic Start and Shutdown of Containers
572 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
574 To automatically start a container when the host system boots, select the
575 option 'Start at boot' in the 'Options' panel of the container in the web
576 interface or run the following command:
579 # pct set CTID -onboot 1
582 .Start and Shutdown Order
583 // use the screenshot from qemu - its the same
584 [thumbnail="screenshot/gui-qemu-edit-start-order.png"]
586 If you want to fine tune the boot order of your containers, you can use the
587 following parameters:
589 * *Start/Shutdown order*: Defines the start order priority. For example, set it
590 to 1 if you want the CT to be the first to be started. (We use the reverse
591 startup order for shutdown, so a container with a start order of 1 would be
592 the last to be shut down)
593 * *Startup delay*: Defines the interval between this container start and
594 subsequent containers starts. For example, set it to 240 if you want to wait
595 240 seconds before starting other containers.
596 * *Shutdown timeout*: Defines the duration in seconds {pve} should wait
597 for the container to be offline after issuing a shutdown command.
598 By default this value is set to 60, which means that {pve} will issue a
599 shutdown request, wait 60s for the machine to be offline, and if after 60s
600 the machine is still online will notify that the shutdown action failed.
602 Please note that containers without a Start/Shutdown order parameter will
603 always start after those where the parameter is set, and this parameter only
604 makes sense between the machines running locally on a host, and not
607 If you require a delay between the host boot and the booting of the first
608 container, see the section on
609 xref:first_guest_boot_delay[Proxmox VE Node Management].
615 You can add a hook script to CTs with the config property `hookscript`.
618 # pct set 100 -hookscript local:snippets/hookscript.pl
621 It will be called during various phases of the guests lifetime. For an example
622 and documentation see the example script under
623 `/usr/share/pve-docs/examples/guest-example-hookscript.pl`.
625 Security Considerations
626 -----------------------
628 Containers use the kernel of the host system. This exposes an attack surface
629 for malicious users. In general, full virtual machines provide better
630 isolation. This should be considered if containers are provided to unknown or
633 To reduce the attack surface, LXC uses many security features like AppArmor,
634 CGroups and kernel namespaces.
639 AppArmor profiles are used to restrict access to possibly dangerous actions.
640 Some system calls, i.e. `mount`, are prohibited from execution.
642 To trace AppArmor activity, use:
645 # dmesg | grep apparmor
648 Although it is not recommended, AppArmor can be disabled for a container. This
649 brings security risks with it. Some syscalls can lead to privilege escalation
650 when executed within a container if the system is misconfigured or if a LXC or
651 Linux Kernel vulnerability exists.
653 To disable AppArmor for a container, add the following line to the container
654 configuration file located at `/etc/pve/lxc/CTID.conf`:
657 lxc.apparmor.profile = unconfined
660 WARNING: Please note that this is not recommended for production use.
664 Control Groups ('cgroup')
665 ~~~~~~~~~~~~~~~~~~~~~~~~~
668 mechanism used to hierarchically organize processes and distribute system
671 The main resources controlled via 'cgroups' are CPU time, memory and swap
672 limits, and access to device nodes. 'cgroups' are also used to "freeze" a
673 container before taking snapshots.
675 There are 2 versions of 'cgroups' currently available,
676 https://www.kernel.org/doc/html/v5.11/admin-guide/cgroup-v1/index.html[legacy]
678 https://www.kernel.org/doc/html/v5.11/admin-guide/cgroup-v2.html['cgroupv2'].
680 Since {pve} 7.0, the default is a pure 'cgroupv2' environment. Previously a
681 "hybrid" setup was used, where resource control was mainly done in 'cgroupv1'
682 with an additional 'cgroupv2' controller which could take over some subsystems
683 via the 'cgroup_no_v1' kernel command-line parameter. (See the
684 https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html[kernel
685 parameter documentation] for details.)
687 [[pct_cgroup_compat]]
688 CGroup Version Compatibility
689 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
690 The main difference between pure 'cgroupv2' and the old hybrid environments
691 regarding {pve} is that with 'cgroupv2' memory and swap are now controlled
692 independently. The memory and swap settings for containers can map directly to
693 these values, whereas previously only the memory limit and the limit of the
694 *sum* of memory and swap could be limited.
696 Another important difference is that the 'devices' controller is configured in a
697 completely different way. Because of this, file system quotas are currently not
698 supported in a pure 'cgroupv2' environment.
700 'cgroupv2' support by the container's OS is needed to run in a pure 'cgroupv2'
701 environment. Containers running 'systemd' version 231 or newer support
702 'cgroupv2' footnote:[this includes all newest major versions of container
703 templates shipped by {pve}], as do containers not using 'systemd' as init
704 system footnote:[for example Alpine Linux].
708 CentOS 7 and Ubuntu 16.10 are two prominent Linux distributions releases,
709 which have a 'systemd' version that is too old to run in a 'cgroupv2'
710 environment, you can either
712 * Upgrade the whole distribution to a newer release. For the examples above, that
713 could be Ubuntu 18.04 or 20.04, and CentOS 8 (or RHEL/CentOS derivatives like
714 AlmaLinux or Rocky Linux). This has the benefit to get the newest bug and
715 security fixes, often also new features, and moving the EOL date in the future.
717 * Upgrade the Containers systemd version. If the distribution provides a
718 backports repository this can be an easy and quick stop-gap measurement.
720 * Move the container, or its services, to a Virtual Machine. Virtual Machines
721 have a much less interaction with the host, that's why one can install
722 decades old OS versions just fine there.
724 * Switch back to the legacy 'cgroup' controller. Note that while it can be a
725 valid solution, it's not a permanent one. Starting from {pve} 9.0, the legacy
726 controller will not be supported anymore.
729 [[pct_cgroup_change_version]]
730 Changing CGroup Version
731 ^^^^^^^^^^^^^^^^^^^^^^^
733 TIP: If file system quotas are not required and all containers support 'cgroupv2',
734 it is recommended to stick to the new default.
736 To switch back to the previous version the following kernel command-line
737 parameter can be used:
740 systemd.unified_cgroup_hierarchy=0
743 See xref:sysboot_edit_kernel_cmdline[this section] on editing the kernel boot
744 command line on where to add the parameter.
746 // TODO: seccomp a bit more.
747 // TODO: pve-lxc-syscalld
750 Guest Operating System Configuration
751 ------------------------------------
753 {pve} tries to detect the Linux distribution in the container, and modifies
754 some files. Here is a short list of things done at container startup:
756 set /etc/hostname:: to set the container name
758 modify /etc/hosts:: to allow lookup of the local hostname
760 network setup:: pass the complete network setup to the container
762 configure DNS:: pass information about DNS servers
764 adapt the init system:: for example, fix the number of spawned getty processes
766 set the root password:: when creating a new container
768 rewrite ssh_host_keys:: so that each container has unique keys
770 randomize crontab:: so that cron does not start at the same time on all containers
772 Changes made by {PVE} are enclosed by comment markers:
780 Those markers will be inserted at a reasonable location in the file. If such a
781 section already exists, it will be updated in place and will not be moved.
783 Modification of a file can be prevented by adding a `.pve-ignore.` file for it.
784 For instance, if the file `/etc/.pve-ignore.hosts` exists then the `/etc/hosts`
785 file will not be touched. This can be a simple empty file created via:
788 # touch /etc/.pve-ignore.hosts
791 Most modifications are OS dependent, so they differ between different
792 distributions and versions. You can completely disable modifications by
793 manually setting the `ostype` to `unmanaged`.
795 OS type detection is done by testing for certain files inside the
796 container. {pve} first checks the `/etc/os-release` file
797 footnote:[/etc/os-release replaces the multitude of per-distribution
798 release files https://manpages.debian.org/stable/systemd/os-release.5.en.html].
799 If that file is not present, or it does not contain a clearly recognizable
800 distribution identifier the following distribution specific release files are
803 Ubuntu:: inspect /etc/lsb-release (`DISTRIB_ID=Ubuntu`)
805 Debian:: test /etc/debian_version
807 Fedora:: test /etc/fedora-release
809 RedHat or CentOS:: test /etc/redhat-release
811 ArchLinux:: test /etc/arch-release
813 Alpine:: test /etc/alpine-release
815 Gentoo:: test /etc/gentoo-release
817 NOTE: Container start fails if the configured `ostype` differs from the auto
821 [[pct_container_storage]]
825 The {pve} LXC container storage model is more flexible than traditional
826 container storage models. A container can have multiple mount points. This
827 makes it possible to use the best suited storage for each application.
829 For example the root file system of the container can be on slow and cheap
830 storage while the database can be on fast and distributed storage via a second
831 mount point. See section <<pct_mount_points, Mount Points>> for further
834 Any storage type supported by the {pve} storage library can be used. This means
835 that containers can be stored on local (for example `lvm`, `zfs` or directory),
836 shared external (like `iSCSI`, `NFS`) or even distributed storage systems like
837 Ceph. Advanced storage features like snapshots or clones can be used if the
838 underlying storage supports them. The `vzdump` backup tool can use snapshots to
839 provide consistent container backups.
841 Furthermore, local devices or local directories can be mounted directly using
842 'bind mounts'. This gives access to local resources inside a container with
843 practically zero overhead. Bind mounts can be used as an easy way to share data
850 WARNING: Because of existing issues in the Linux kernel's freezer subsystem the
851 usage of FUSE mounts inside a container is strongly advised against, as
852 containers need to be frozen for suspend or snapshot mode backups.
854 If FUSE mounts cannot be replaced by other mounting mechanisms or storage
855 technologies, it is possible to establish the FUSE mount on the Proxmox host
856 and use a bind mount point to make it accessible inside the container.
859 Using Quotas Inside Containers
860 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
862 Quotas allow to set limits inside a container for the amount of disk space that
865 NOTE: This currently requires the use of legacy 'cgroups'.
867 NOTE: This only works on ext4 image based storage types and currently only
868 works with privileged containers.
870 Activating the `quota` option causes the following mount options to be used for
872 `usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0`
874 This allows quotas to be used like on any other system. You can initialize the
875 `/aquota.user` and `/aquota.group` files by running:
882 Then edit the quotas using the `edquota` command. Refer to the documentation of
883 the distribution running inside the container for details.
885 NOTE: You need to run the above commands for every mount point by passing the
886 mount point's path instead of just `/`.
889 Using ACLs Inside Containers
890 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
892 The standard Posix **A**ccess **C**ontrol **L**ists are also available inside
893 containers. ACLs allow you to set more detailed file ownership than the
894 traditional user/group/others model.
897 Backup of Container mount points
898 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
900 To include a mount point in backups, enable the `backup` option for it in the
901 container configuration. For an existing mount point `mp0`
904 mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G
907 add `backup=1` to enable it.
910 mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G,backup=1
913 NOTE: When creating a new mount point in the GUI, this option is enabled by
916 To disable backups for a mount point, add `backup=0` in the way described
917 above, or uncheck the *Backup* checkbox on the GUI.
919 Replication of Containers mount points
920 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
922 By default, additional mount points are replicated when the Root Disk is
923 replicated. If you want the {pve} storage replication mechanism to skip a mount
924 point, you can set the *Skip replication* option for that mount point.
925 As of {pve} 5.0, replication requires a storage of type `zfspool`. Adding a
926 mount point to a different type of storage when the container has replication
927 configured requires to have *Skip replication* enabled for that mount point.
937 It is possible to use the `vzdump` tool for container backup. Please refer to
938 the `vzdump` manual page for details.
941 Restoring Container Backups
942 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
944 Restoring container backups made with `vzdump` is possible using the `pct
945 restore` command. By default, `pct restore` will attempt to restore as much of
946 the backed up container configuration as possible. It is possible to override
947 the backed up configuration by manually setting container options on the
948 command line (see the `pct` manual page for details).
950 NOTE: `pvesm extractconfig` can be used to view the backed up configuration
951 contained in a vzdump archive.
953 There are two basic restore modes, only differing by their handling of mount
957 ``Simple'' Restore Mode
958 ^^^^^^^^^^^^^^^^^^^^^^^
960 If neither the `rootfs` parameter nor any of the optional `mpX` parameters are
961 explicitly set, the mount point configuration from the backed up configuration
962 file is restored using the following steps:
964 . Extract mount points and their options from backup
965 . Create volumes for storage backed mount points on the storage provided with
966 the `storage` parameter (default: `local`).
967 . Extract files from backup archive
968 . Add bind and device mount points to restored configuration (limited to root
971 NOTE: Since bind and device mount points are never backed up, no files are
972 restored in the last step, but only the configuration options. The assumption
973 is that such mount points are either backed up with another mechanism (e.g.,
974 NFS space that is bind mounted into many containers), or not intended to be
977 This simple mode is also used by the container restore operations in the web
981 ``Advanced'' Restore Mode
982 ^^^^^^^^^^^^^^^^^^^^^^^^^
984 By setting the `rootfs` parameter (and optionally, any combination of `mpX`
985 parameters), the `pct restore` command is automatically switched into an
986 advanced mode. This advanced mode completely ignores the `rootfs` and `mpX`
987 configuration options contained in the backup archive, and instead only uses
988 the options explicitly provided as parameters.
990 This mode allows flexible configuration of mount point settings at restore
993 * Set target storages, volume sizes and other options for each mount point
995 * Redistribute backed up files according to new mount point scheme
996 * Restore to device and/or bind mount points (limited to root user)
999 Managing Containers with `pct`
1000 ------------------------------
1002 The ``Proxmox Container Toolkit'' (`pct`) is the command-line tool to manage
1003 {pve} containers. It enables you to create or destroy containers, as well as
1004 control the container execution (start, stop, reboot, migrate, etc.). It can be
1005 used to set parameters in the config file of a container, for example the
1006 network configuration or memory limits.
1011 Create a container based on a Debian template (provided you have already
1012 downloaded the template via the web interface)
1015 # pct create 100 /var/lib/vz/template/cache/debian-10.0-standard_10.0-1_amd64.tar.gz
1024 Start a login session via getty
1030 Enter the LXC namespace and run a shell as root user
1036 Display the configuration
1042 Add a network interface called `eth0`, bridged to the host bridge `vmbr0`, set
1043 the address and gateway, while it's running
1046 # pct set 100 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.147/24,gw=192.168.15.1
1049 Reduce the memory of the container to 512MB
1052 # pct set 100 -memory 512
1055 Destroying a container always removes it from Access Control Lists and it always
1056 removes the firewall configuration of the container. You have to activate
1057 '--purge', if you want to additionally remove the container from replication jobs,
1058 backup jobs and HA resource configurations.
1061 # pct destroy 100 --purge
1064 Move a mount point volume to a different storage.
1067 # pct move-volume 100 mp0 other-storage
1070 Reassign a volume to a different CT. This will remove the volume `mp0` from
1071 the source CT and attaches it as `mp1` to the target CT. In the background
1072 the volume is being renamed so that the name matches the new owner.
1075 # pct move-volume 100 mp0 --target-vmid 200 --target-volume mp1
1079 Obtaining Debugging Logs
1080 ~~~~~~~~~~~~~~~~~~~~~~~~
1082 In case `pct start` is unable to start a specific container, it might be
1083 helpful to collect debugging output by passing the `--debug` flag (replace `CTID` with
1084 the container's CTID):
1087 # pct start CTID --debug
1090 Alternatively, you can use the following `lxc-start` command, which will save
1091 the debug log to the file specified by the `-o` output option:
1094 # lxc-start -n CTID -F -l DEBUG -o /tmp/lxc-CTID.log
1097 This command will attempt to start the container in foreground mode, to stop
1098 the container run `pct shutdown CTID` or `pct stop CTID` in a second terminal.
1100 The collected debug log is written to `/tmp/lxc-CTID.log`.
1102 NOTE: If you have changed the container's configuration since the last start
1103 attempt with `pct start`, you need to run `pct start` at least once to also
1104 update the configuration used by `lxc-start`.
1110 If you have a cluster, you can migrate your Containers with
1113 # pct migrate <ctid> <target>
1116 This works as long as your Container is offline. If it has local volumes or
1117 mount points defined, the migration will copy the content over the network to
1118 the target host if the same storage is defined there.
1120 Running containers cannot live-migrated due to technical limitations. You can
1121 do a restart migration, which shuts down, moves and then starts a container
1122 again on the target node. As containers are very lightweight, this results
1123 normally only in a downtime of some hundreds of milliseconds.
1125 A restart migration can be done through the web interface or by using the
1126 `--restart` flag with the `pct migrate` command.
1128 A restart migration will shut down the Container and kill it after the
1129 specified timeout (the default is 180 seconds). Then it will migrate the
1130 Container like an offline migration and when finished, it starts the Container
1133 [[pct_configuration]]
1137 The `/etc/pve/lxc/<CTID>.conf` file stores container configuration, where
1138 `<CTID>` is the numeric ID of the given container. Like all other files stored
1139 inside `/etc/pve/`, they get automatically replicated to all other cluster
1142 NOTE: CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
1143 unique cluster wide.
1145 .Example Container Configuration
1152 net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
1153 rootfs: local:107/vm-107-disk-1.raw,size=7G
1156 The configuration files are simple text files. You can edit them using a normal
1157 text editor, for example, `vi` or `nano`.
1158 This is sometimes useful to do small corrections, but keep in mind that you
1159 need to restart the container to apply such changes.
1161 For that reason, it is usually better to use the `pct` command to generate and
1162 modify those files, or do the whole thing using the GUI.
1163 Our toolkit is smart enough to instantaneously apply most changes to running
1164 containers. This feature is called ``hot plug'', and there is no need to restart
1165 the container in that case.
1167 In cases where a change cannot be hot-plugged, it will be registered as a
1168 pending change (shown in red color in the GUI).
1169 They will only be applied after rebooting the container.
1175 The container configuration file uses a simple colon separated key/value
1176 format. Each line has the following format:
1183 Blank lines in those files are ignored, and lines starting with a `#` character
1184 are treated as comments and are also ignored.
1186 It is possible to add low-level, LXC style configuration directly, for example:
1189 lxc.init_cmd: /sbin/my_own_init
1195 lxc.init_cmd = /sbin/my_own_init
1198 The settings are passed directly to the LXC low-level tools.
1205 When you create a snapshot, `pct` stores the configuration at snapshot time
1206 into a separate snapshot section within the same configuration file. For
1207 example, after creating a snapshot called ``testsnapshot'', your configuration
1208 file will look like this:
1210 .Container configuration with snapshot
1220 snaptime: 1457170803
1224 There are a few snapshot related properties like `parent` and `snaptime`. The
1225 `parent` property is used to store the parent/child relationship between
1226 snapshots. `snaptime` is the snapshot creation time stamp (Unix epoch).
1233 include::pct.conf.5-opts.adoc[]
1239 Container migrations, snapshots and backups (`vzdump`) set a lock to prevent
1240 incompatible concurrent actions on the affected container. Sometimes you need
1241 to remove such a lock manually (e.g., after a power failure).
1247 CAUTION: Only do this if you are sure the action which set the lock is no
1256 `/etc/pve/lxc/<CTID>.conf`::
1258 Configuration file for the container '<CTID>'.
1261 include::pve-copyright.adoc[]