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  1. [[chapter_pct]]
  2. ifdef::manvolnum[]
  3. pct(1)
  4. ======
  5. :pve-toplevel:
  6. NAME
  7. ----
  8. pct - Tool to manage Linux Containers (LXC) on Proxmox VE
  9. SYNOPSIS
  10. --------
  11. include::pct.1-synopsis.adoc[]
  12. DESCRIPTION
  13. -----------
  14. endif::manvolnum[]
  15. ifndef::manvolnum[]
  16. Proxmox Container Toolkit
  17. =========================
  18. :pve-toplevel:
  19. endif::manvolnum[]
  20. ifdef::wiki[]
  21. :title: Linux Container
  22. endif::wiki[]
  23. Containers are a lightweight alternative to fully virtualized machines (VMs).
  24. They use the kernel of the host system that they run on, instead of emulating a
  25. full operating system (OS). This means that containers can access resources on
  26. the host system directly.
  27. The runtime costs for containers is low, usually negligible. However, there are
  28. some drawbacks that need be considered:
  29. * Only Linux distributions can be run in containers. It is not possible to run
  30. other Operating Systems like, for example, FreeBSD or Microsoft Windows
  31. inside a container.
  32. * For security reasons, access to host resources needs to be restricted.
  33. Containers run in their own separate namespaces. Additionally some syscalls
  34. are not allowed within containers.
  35. {pve} uses https://linuxcontainers.org/[Linux Containers (LXC)] as underlying
  36. container technology. The ``Proxmox Container Toolkit'' (`pct`) simplifies the
  37. usage and management of LXC containers.
  38. Containers are tightly integrated with {pve}. This means that they are aware of
  39. the cluster setup, and they can use the same network and storage resources as
  40. virtual machines. You can also use the {pve} firewall, or manage containers
  41. using the HA framework.
  42. Our primary goal is to offer an environment as one would get from a VM, but
  43. without the additional overhead. We call this ``System Containers''.
  44. NOTE: If you want to run micro-containers, for example, 'Docker' or 'rkt', it
  45. is best to run them inside a VM.
  46. Technology Overview
  47. -------------------
  48. * LXC (https://linuxcontainers.org/)
  49. * Integrated into {pve} graphical web user interface (GUI)
  50. * Easy to use command line tool `pct`
  51. * Access via {pve} REST API
  52. * 'lxcfs' to provide containerized /proc file system
  53. * Control groups ('cgroups') for resource isolation and limitation
  54. * 'AppArmor' and 'seccomp' to improve security
  55. * Modern Linux kernels
  56. * Image based deployment (templates)
  57. * Uses {pve} xref:chapter_storage[storage library]
  58. * Container setup from host (network, DNS, storage, etc.)
  59. [[pct_container_images]]
  60. Container Images
  61. ----------------
  62. Container images, sometimes also referred to as ``templates'' or
  63. ``appliances'', are `tar` archives which contain everything to run a container.
  64. {pve} itself provides a variety of basic templates for the most common Linux
  65. distributions. They can be downloaded using the GUI or the `pveam` (short for
  66. {pve} Appliance Manager) command line utility.
  67. Additionally, https://www.turnkeylinux.org/[TurnKey Linux] container templates
  68. are also available to download.
  69. The list of available templates is updated daily through the 'pve-daily-update'
  70. timer. You can also trigger an update manually by executing:
  71. ----
  72. # pveam update
  73. ----
  74. To view the list of available images run:
  75. ----
  76. # pveam available
  77. ----
  78. You can restrict this large list by specifying the `section` you are
  79. interested in, for example basic `system` images:
  80. .List available system images
  81. ----
  82. # pveam available --section system
  83. system alpine-3.10-default_20190626_amd64.tar.xz
  84. system alpine-3.9-default_20190224_amd64.tar.xz
  85. system archlinux-base_20190924-1_amd64.tar.gz
  86. system centos-6-default_20191016_amd64.tar.xz
  87. system centos-7-default_20190926_amd64.tar.xz
  88. system centos-8-default_20191016_amd64.tar.xz
  89. system debian-10.0-standard_10.0-1_amd64.tar.gz
  90. system debian-8.0-standard_8.11-1_amd64.tar.gz
  91. system debian-9.0-standard_9.7-1_amd64.tar.gz
  92. system fedora-30-default_20190718_amd64.tar.xz
  93. system fedora-31-default_20191029_amd64.tar.xz
  94. system gentoo-current-default_20190718_amd64.tar.xz
  95. system opensuse-15.0-default_20180907_amd64.tar.xz
  96. system opensuse-15.1-default_20190719_amd64.tar.xz
  97. system ubuntu-16.04-standard_16.04.5-1_amd64.tar.gz
  98. system ubuntu-18.04-standard_18.04.1-1_amd64.tar.gz
  99. system ubuntu-19.04-standard_19.04-1_amd64.tar.gz
  100. system ubuntu-19.10-standard_19.10-1_amd64.tar.gz
  101. ----
  102. Before you can use such a template, you need to download them into one of your
  103. storages. If you're unsure to which one, you can simply use the `local` named
  104. storage for that purpose. For clustered installations, it is preferred to use a
  105. shared storage so that all nodes can access those images.
  106. ----
  107. # pveam download local debian-10.0-standard_10.0-1_amd64.tar.gz
  108. ----
  109. You are now ready to create containers using that image, and you can list all
  110. downloaded images on storage `local` with:
  111. ----
  112. # pveam list local
  113. local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz 219.95MB
  114. ----
  115. TIP: You can also use the {pve} web interface GUI to download, list and delete
  116. container templates.
  117. `pct` uses them to create a new container, for example:
  118. ----
  119. # pct create 999 local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz
  120. ----
  121. The above command shows you the full {pve} volume identifiers. They include the
  122. storage name, and most other {pve} commands can use them. For example you can
  123. delete that image later with:
  124. ----
  125. # pveam remove local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.gz
  126. ----
  127. [[pct_settings]]
  128. Container Settings
  129. ------------------
  130. [[pct_general]]
  131. General Settings
  132. ~~~~~~~~~~~~~~~~
  133. [thumbnail="screenshot/gui-create-ct-general.png"]
  134. General settings of a container include
  135. * the *Node* : the physical server on which the container will run
  136. * the *CT ID*: a unique number in this {pve} installation used to identify your
  137. container
  138. * *Hostname*: the hostname of the container
  139. * *Resource Pool*: a logical group of containers and VMs
  140. * *Password*: the root password of the container
  141. * *SSH Public Key*: a public key for connecting to the root account over SSH
  142. * *Unprivileged container*: this option allows to choose at creation time
  143. if you want to create a privileged or unprivileged container.
  144. Unprivileged Containers
  145. ^^^^^^^^^^^^^^^^^^^^^^^
  146. Unprivileged containers use a new kernel feature called user namespaces.
  147. The root UID 0 inside the container is mapped to an unprivileged user outside
  148. the container. This means that most security issues (container escape, resource
  149. abuse, etc.) in these containers will affect a random unprivileged user, and
  150. would be a generic kernel security bug rather than an LXC issue. The LXC team
  151. thinks unprivileged containers are safe by design.
  152. This is the default option when creating a new container.
  153. NOTE: If the container uses systemd as an init system, please be aware the
  154. systemd version running inside the container should be equal to or greater than
  155. 220.
  156. Privileged Containers
  157. ^^^^^^^^^^^^^^^^^^^^^
  158. Security in containers is achieved by using mandatory access control 'AppArmor'
  159. restrictions, 'seccomp' filters and Linux kernel namespaces. The LXC team
  160. considers this kind of container as unsafe, and they will not consider new
  161. container escape exploits to be security issues worthy of a CVE and quick fix.
  162. That's why privileged containers should only be used in trusted environments.
  163. [[pct_cpu]]
  164. CPU
  165. ~~~
  166. [thumbnail="screenshot/gui-create-ct-cpu.png"]
  167. You can restrict the number of visible CPUs inside the container using the
  168. `cores` option. This is implemented using the Linux 'cpuset' cgroup
  169. (**c**ontrol *group*).
  170. A special task inside `pvestatd` tries to distribute running containers among
  171. available CPUs periodically.
  172. To view the assigned CPUs run the following command:
  173. ----
  174. # pct cpusets
  175. ---------------------
  176. 102: 6 7
  177. 105: 2 3 4 5
  178. 108: 0 1
  179. ---------------------
  180. ----
  181. Containers use the host kernel directly. All tasks inside a container are
  182. handled by the host CPU scheduler. {pve} uses the Linux 'CFS' (**C**ompletely
  183. **F**air **S**cheduler) scheduler by default, which has additional bandwidth
  184. control options.
  185. [horizontal]
  186. `cpulimit`: :: You can use this option to further limit assigned CPU time.
  187. Please note that this is a floating point number, so it is perfectly valid to
  188. assign two cores to a container, but restrict overall CPU consumption to half a
  189. core.
  190. +
  191. ----
  192. cores: 2
  193. cpulimit: 0.5
  194. ----
  195. `cpuunits`: :: This is a relative weight passed to the kernel scheduler. The
  196. larger the number is, the more CPU time this container gets. Number is relative
  197. to the weights of all the other running containers. The default is 1024. You
  198. can use this setting to prioritize some containers.
  199. [[pct_memory]]
  200. Memory
  201. ~~~~~~
  202. [thumbnail="screenshot/gui-create-ct-memory.png"]
  203. Container memory is controlled using the cgroup memory controller.
  204. [horizontal]
  205. `memory`: :: Limit overall memory usage. This corresponds to the
  206. `memory.limit_in_bytes` cgroup setting.
  207. `swap`: :: Allows the container to use additional swap memory from the host
  208. swap space. This corresponds to the `memory.memsw.limit_in_bytes` cgroup
  209. setting, which is set to the sum of both value (`memory + swap`).
  210. [[pct_mount_points]]
  211. Mount Points
  212. ~~~~~~~~~~~~
  213. [thumbnail="screenshot/gui-create-ct-root-disk.png"]
  214. The root mount point is configured with the `rootfs` property. You can
  215. configure up to 256 additional mount points. The corresponding options are
  216. called `mp0` to `mp255`. They can contain the following settings:
  217. include::pct-mountpoint-opts.adoc[]
  218. Currently there are three types of mount points: storage backed mount points,
  219. bind mounts, and device mounts.
  220. .Typical container `rootfs` configuration
  221. ----
  222. rootfs: thin1:base-100-disk-1,size=8G
  223. ----
  224. Storage Backed Mount Points
  225. ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  226. Storage backed mount points are managed by the {pve} storage subsystem and come
  227. in three different flavors:
  228. - Image based: these are raw images containing a single ext4 formatted file
  229. system.
  230. - ZFS subvolumes: these are technically bind mounts, but with managed storage,
  231. and thus allow resizing and snapshotting.
  232. - Directories: passing `size=0` triggers a special case where instead of a raw
  233. image a directory is created.
  234. NOTE: The special option syntax `STORAGE_ID:SIZE_IN_GB` for storage backed
  235. mount point volumes will automatically allocate a volume of the specified size
  236. on the specified storage. For example, calling
  237. ----
  238. pct set 100 -mp0 thin1:10,mp=/path/in/container
  239. ----
  240. will allocate a 10GB volume on the storage `thin1` and replace the volume ID
  241. place holder `10` with the allocated volume ID, and setup the moutpoint in the
  242. container at `/path/in/container`
  243. Bind Mount Points
  244. ^^^^^^^^^^^^^^^^^
  245. Bind mounts allow you to access arbitrary directories from your Proxmox VE host
  246. inside a container. Some potential use cases are:
  247. - Accessing your home directory in the guest
  248. - Accessing an USB device directory in the guest
  249. - Accessing an NFS mount from the host in the guest
  250. Bind mounts are considered to not be managed by the storage subsystem, so you
  251. cannot make snapshots or deal with quotas from inside the container. With
  252. unprivileged containers you might run into permission problems caused by the
  253. user mapping and cannot use ACLs.
  254. NOTE: The contents of bind mount points are not backed up when using `vzdump`.
  255. WARNING: For security reasons, bind mounts should only be established using
  256. source directories especially reserved for this purpose, e.g., a directory
  257. hierarchy under `/mnt/bindmounts`. Never bind mount system directories like
  258. `/`, `/var` or `/etc` into a container - this poses a great security risk.
  259. NOTE: The bind mount source path must not contain any symlinks.
  260. For example, to make the directory `/mnt/bindmounts/shared` accessible in the
  261. container with ID `100` under the path `/shared`, use a configuration line like
  262. `mp0: /mnt/bindmounts/shared,mp=/shared` in `/etc/pve/lxc/100.conf`.
  263. Alternatively, use `pct set 100 -mp0 /mnt/bindmounts/shared,mp=/shared` to
  264. achieve the same result.
  265. Device Mount Points
  266. ^^^^^^^^^^^^^^^^^^^
  267. Device mount points allow to mount block devices of the host directly into the
  268. container. Similar to bind mounts, device mounts are not managed by {PVE}'s
  269. storage subsystem, but the `quota` and `acl` options will be honored.
  270. NOTE: Device mount points should only be used under special circumstances. In
  271. most cases a storage backed mount point offers the same performance and a lot
  272. more features.
  273. NOTE: The contents of device mount points are not backed up when using
  274. `vzdump`.
  275. [[pct_container_network]]
  276. Network
  277. ~~~~~~~
  278. [thumbnail="screenshot/gui-create-ct-network.png"]
  279. You can configure up to 10 network interfaces for a single container.
  280. The corresponding options are called `net0` to `net9`, and they can contain the
  281. following setting:
  282. include::pct-network-opts.adoc[]
  283. [[pct_startup_and_shutdown]]
  284. Automatic Start and Shutdown of Containers
  285. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  286. To automatically start a container when the host system boots, select the
  287. option 'Start at boot' in the 'Options' panel of the container in the web
  288. interface or run the following command:
  289. ----
  290. # pct set CTID -onboot 1
  291. ----
  292. .Start and Shutdown Order
  293. // use the screenshot from qemu - its the same
  294. [thumbnail="screenshot/gui-qemu-edit-start-order.png"]
  295. If you want to fine tune the boot order of your containers, you can use the
  296. following parameters:
  297. * *Start/Shutdown order*: Defines the start order priority. For example, set it
  298. to 1 if you want the CT to be the first to be started. (We use the reverse
  299. startup order for shutdown, so a container with a start order of 1 would be
  300. the last to be shut down)
  301. * *Startup delay*: Defines the interval between this container start and
  302. subsequent containers starts. For example, set it to 240 if you want to wait
  303. 240 seconds before starting other containers.
  304. * *Shutdown timeout*: Defines the duration in seconds {pve} should wait
  305. for the container to be offline after issuing a shutdown command.
  306. By default this value is set to 60, which means that {pve} will issue a
  307. shutdown request, wait 60s for the machine to be offline, and if after 60s
  308. the machine is still online will notify that the shutdown action failed.
  309. Please note that containers without a Start/Shutdown order parameter will
  310. always start after those where the parameter is set, and this parameter only
  311. makes sense between the machines running locally on a host, and not
  312. cluster-wide.
  313. Hookscripts
  314. ~~~~~~~~~~~
  315. You can add a hook script to CTs with the config property `hookscript`.
  316. ----
  317. # pct set 100 -hookscript local:snippets/hookscript.pl
  318. ----
  319. It will be called during various phases of the guests lifetime. For an example
  320. and documentation see the example script under
  321. `/usr/share/pve-docs/examples/guest-example-hookscript.pl`.
  322. Security Considerations
  323. -----------------------
  324. Containers use the kernel of the host system. This exposes an attack surface
  325. for malicious users. In general, full virtual machines provide better
  326. isolation. This should be considered if containers are provided to unknown or
  327. untrusted people.
  328. To reduce the attack surface, LXC uses many security features like AppArmor,
  329. CGroups and kernel namespaces.
  330. AppArmor
  331. ~~~~~~~~
  332. AppArmor profiles are used to restrict access to possibly dangerous actions.
  333. Some system calls, i.e. `mount`, are prohibited from execution.
  334. To trace AppArmor activity, use:
  335. ----
  336. # dmesg | grep apparmor
  337. ----
  338. Although it is not recommended, AppArmor can be disabled for a container. This
  339. brings security risks with it. Some syscalls can lead to privilege escalation
  340. when executed within a container if the system is misconfigured or if a LXC or
  341. Linux Kernel vulnerability exists.
  342. To disable AppArmor for a container, add the following line to the container
  343. configuration file located at `/etc/pve/lxc/CTID.conf`:
  344. ----
  345. lxc.apparmor_profile = unconfined
  346. ----
  347. WARNING: Please note that this is not recommended for production use.
  348. // TODO: describe cgroups + seccomp a bit more.
  349. // TODO: pve-lxc-syscalld
  350. Guest Operating System Configuration
  351. ------------------------------------
  352. {pve} tries to detect the Linux distribution in the container, and modifies
  353. some files. Here is a short list of things done at container startup:
  354. set /etc/hostname:: to set the container name
  355. modify /etc/hosts:: to allow lookup of the local hostname
  356. network setup:: pass the complete network setup to the container
  357. configure DNS:: pass information about DNS servers
  358. adapt the init system:: for example, fix the number of spawned getty processes
  359. set the root password:: when creating a new container
  360. rewrite ssh_host_keys:: so that each container has unique keys
  361. randomize crontab:: so that cron does not start at the same time on all containers
  362. Changes made by {PVE} are enclosed by comment markers:
  363. ----
  364. # --- BEGIN PVE ---
  365. <data>
  366. # --- END PVE ---
  367. ----
  368. Those markers will be inserted at a reasonable location in the file. If such a
  369. section already exists, it will be updated in place and will not be moved.
  370. Modification of a file can be prevented by adding a `.pve-ignore.` file for it.
  371. For instance, if the file `/etc/.pve-ignore.hosts` exists then the `/etc/hosts`
  372. file will not be touched. This can be a simple empty file created via:
  373. ----
  374. # touch /etc/.pve-ignore.hosts
  375. ----
  376. Most modifications are OS dependent, so they differ between different
  377. distributions and versions. You can completely disable modifications by
  378. manually setting the `ostype` to `unmanaged`.
  379. OS type detection is done by testing for certain files inside the
  380. container. {pve} first checks the `/etc/os-release` file
  381. footnote:[/etc/os-release replaces the multitude of per-distribution
  382. release files https://manpages.debian.org/stable/systemd/os-release.5.en.html].
  383. If that file is not present, or it does not contain a clearly recognizable
  384. distribution identifier the following distribution specific release files are
  385. checked.
  386. Ubuntu:: inspect /etc/lsb-release (`DISTRIB_ID=Ubuntu`)
  387. Debian:: test /etc/debian_version
  388. Fedora:: test /etc/fedora-release
  389. RedHat or CentOS:: test /etc/redhat-release
  390. ArchLinux:: test /etc/arch-release
  391. Alpine:: test /etc/alpine-release
  392. Gentoo:: test /etc/gentoo-release
  393. NOTE: Container start fails if the configured `ostype` differs from the auto
  394. detected type.
  395. [[pct_container_storage]]
  396. Container Storage
  397. -----------------
  398. The {pve} LXC container storage model is more flexible than traditional
  399. container storage models. A container can have multiple mount points. This
  400. makes it possible to use the best suited storage for each application.
  401. For example the root file system of the container can be on slow and cheap
  402. storage while the database can be on fast and distributed storage via a second
  403. mount point. See section <<pct_mount_points, Mount Points>> for further
  404. details.
  405. Any storage type supported by the {pve} storage library can be used. This means
  406. that containers can be stored on local (for example `lvm`, `zfs` or directory),
  407. shared external (like `iSCSI`, `NFS`) or even distributed storage systems like
  408. Ceph. Advanced storage features like snapshots or clones can be used if the
  409. underlying storage supports them. The `vzdump` backup tool can use snapshots to
  410. provide consistent container backups.
  411. Furthermore, local devices or local directories can be mounted directly using
  412. 'bind mounts'. This gives access to local resources inside a container with
  413. practically zero overhead. Bind mounts can be used as an easy way to share data
  414. between containers.
  415. FUSE Mounts
  416. ~~~~~~~~~~~
  417. WARNING: Because of existing issues in the Linux kernel's freezer subsystem the
  418. usage of FUSE mounts inside a container is strongly advised against, as
  419. containers need to be frozen for suspend or snapshot mode backups.
  420. If FUSE mounts cannot be replaced by other mounting mechanisms or storage
  421. technologies, it is possible to establish the FUSE mount on the Proxmox host
  422. and use a bind mount point to make it accessible inside the container.
  423. Using Quotas Inside Containers
  424. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  425. Quotas allow to set limits inside a container for the amount of disk space that
  426. each user can use.
  427. NOTE: This only works on ext4 image based storage types and currently only
  428. works with privileged containers.
  429. Activating the `quota` option causes the following mount options to be used for
  430. a mount point:
  431. `usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0`
  432. This allows quotas to be used like on any other system. You can initialize the
  433. `/aquota.user` and `/aquota.group` files by running:
  434. ----
  435. # quotacheck -cmug /
  436. # quotaon /
  437. ----
  438. Then edit the quotas using the `edquota` command. Refer to the documentation of
  439. the distribution running inside the container for details.
  440. NOTE: You need to run the above commands for every mount point by passing the
  441. mount point's path instead of just `/`.
  442. Using ACLs Inside Containers
  443. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  444. The standard Posix **A**ccess **C**ontrol **L**ists are also available inside
  445. containers. ACLs allow you to set more detailed file ownership than the
  446. traditional user/group/others model.
  447. Backup of Container mount points
  448. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  449. To include a mount point in backups, enable the `backup` option for it in the
  450. container configuration. For an existing mount point `mp0`
  451. ----
  452. mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G
  453. ----
  454. add `backup=1` to enable it.
  455. ----
  456. mp0: guests:subvol-100-disk-1,mp=/root/files,size=8G,backup=1
  457. ----
  458. NOTE: When creating a new mount point in the GUI, this option is enabled by
  459. default.
  460. To disable backups for a mount point, add `backup=0` in the way described
  461. above, or uncheck the *Backup* checkbox on the GUI.
  462. Replication of Containers mount points
  463. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  464. By default, additional mount points are replicated when the Root Disk is
  465. replicated. If you want the {pve} storage replication mechanism to skip a mount
  466. point, you can set the *Skip replication* option for that mount point.
  467. As of {pve} 5.0, replication requires a storage of type `zfspool`. Adding a
  468. mount point to a different type of storage when the container has replication
  469. configured requires to have *Skip replication* enabled for that mount point.
  470. Backup and Restore
  471. ------------------
  472. Container Backup
  473. ~~~~~~~~~~~~~~~~
  474. It is possible to use the `vzdump` tool for container backup. Please refer to
  475. the `vzdump` manual page for details.
  476. Restoring Container Backups
  477. ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  478. Restoring container backups made with `vzdump` is possible using the `pct
  479. restore` command. By default, `pct restore` will attempt to restore as much of
  480. the backed up container configuration as possible. It is possible to override
  481. the backed up configuration by manually setting container options on the
  482. command line (see the `pct` manual page for details).
  483. NOTE: `pvesm extractconfig` can be used to view the backed up configuration
  484. contained in a vzdump archive.
  485. There are two basic restore modes, only differing by their handling of mount
  486. points:
  487. ``Simple'' Restore Mode
  488. ^^^^^^^^^^^^^^^^^^^^^^^
  489. If neither the `rootfs` parameter nor any of the optional `mpX` parameters are
  490. explicitly set, the mount point configuration from the backed up configuration
  491. file is restored using the following steps:
  492. . Extract mount points and their options from backup
  493. . Create volumes for storage backed mount points (on storage provided with the
  494. `storage` parameter, or default local storage if unset)
  495. . Extract files from backup archive
  496. . Add bind and device mount points to restored configuration (limited to root
  497. user)
  498. NOTE: Since bind and device mount points are never backed up, no files are
  499. restored in the last step, but only the configuration options. The assumption
  500. is that such mount points are either backed up with another mechanism (e.g.,
  501. NFS space that is bind mounted into many containers), or not intended to be
  502. backed up at all.
  503. This simple mode is also used by the container restore operations in the web
  504. interface.
  505. ``Advanced'' Restore Mode
  506. ^^^^^^^^^^^^^^^^^^^^^^^^^
  507. By setting the `rootfs` parameter (and optionally, any combination of `mpX`
  508. parameters), the `pct restore` command is automatically switched into an
  509. advanced mode. This advanced mode completely ignores the `rootfs` and `mpX`
  510. configuration options contained in the backup archive, and instead only uses
  511. the options explicitly provided as parameters.
  512. This mode allows flexible configuration of mount point settings at restore
  513. time, for example:
  514. * Set target storages, volume sizes and other options for each mount point
  515. individually
  516. * Redistribute backed up files according to new mount point scheme
  517. * Restore to device and/or bind mount points (limited to root user)
  518. Managing Containers with `pct`
  519. ------------------------------
  520. The ``Proxmox Container Toolkit'' (`pct`) is the command line tool to manage
  521. {pve} containers. It enables you to create or destroy containers, as well as
  522. control the container execution (start, stop, reboot, migrate, etc.). It can be
  523. used to set parameters in the config file of a container, for example the
  524. network configuration or memory limits.
  525. CLI Usage Examples
  526. ~~~~~~~~~~~~~~~~~~
  527. Create a container based on a Debian template (provided you have already
  528. downloaded the template via the web interface)
  529. ----
  530. # pct create 100 /var/lib/vz/template/cache/debian-10.0-standard_10.0-1_amd64.tar.gz
  531. ----
  532. Start container 100
  533. ----
  534. # pct start 100
  535. ----
  536. Start a login session via getty
  537. ----
  538. # pct console 100
  539. ----
  540. Enter the LXC namespace and run a shell as root user
  541. ----
  542. # pct enter 100
  543. ----
  544. Display the configuration
  545. ----
  546. # pct config 100
  547. ----
  548. Add a network interface called `eth0`, bridged to the host bridge `vmbr0`, set
  549. the address and gateway, while it's running
  550. ----
  551. # pct set 100 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.147/24,gw=192.168.15.1
  552. ----
  553. Reduce the memory of the container to 512MB
  554. ----
  555. # pct set 100 -memory 512
  556. ----
  557. Obtaining Debugging Logs
  558. ~~~~~~~~~~~~~~~~~~~~~~~~
  559. In case `pct start` is unable to start a specific container, it might be
  560. helpful to collect debugging output by running `lxc-start` (replace `ID` with
  561. the container's ID):
  562. ----
  563. # lxc-start -n ID -F -l DEBUG -o /tmp/lxc-ID.log
  564. ----
  565. This command will attempt to start the container in foreground mode, to stop
  566. the container run `pct shutdown ID` or `pct stop ID` in a second terminal.
  567. The collected debug log is written to `/tmp/lxc-ID.log`.
  568. NOTE: If you have changed the container's configuration since the last start
  569. attempt with `pct start`, you need to run `pct start` at least once to also
  570. update the configuration used by `lxc-start`.
  571. [[pct_migration]]
  572. Migration
  573. ---------
  574. If you have a cluster, you can migrate your Containers with
  575. ----
  576. # pct migrate <ctid> <target>
  577. ----
  578. This works as long as your Container is offline. If it has local volumes or
  579. mount points defined, the migration will copy the content over the network to
  580. the target host if the same storage is defined there.
  581. Running containers cannot live-migrated due to technical limitations. You can
  582. do a restart migration, which shuts down, moves and then starts a container
  583. again on the target node. As containers are very lightweight, this results
  584. normally only in a downtime of some hundreds of milliseconds.
  585. A restart migration can be done through the web interface or by using the
  586. `--restart` flag with the `pct migrate` command.
  587. A restart migration will shut down the Container and kill it after the
  588. specified timeout (the default is 180 seconds). Then it will migrate the
  589. Container like an offline migration and when finished, it starts the Container
  590. on the target node.
  591. [[pct_configuration]]
  592. Configuration
  593. -------------
  594. The `/etc/pve/lxc/<CTID>.conf` file stores container configuration, where
  595. `<CTID>` is the numeric ID of the given container. Like all other files stored
  596. inside `/etc/pve/`, they get automatically replicated to all other cluster
  597. nodes.
  598. NOTE: CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
  599. unique cluster wide.
  600. .Example Container Configuration
  601. ----
  602. ostype: debian
  603. arch: amd64
  604. hostname: www
  605. memory: 512
  606. swap: 512
  607. net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
  608. rootfs: local:107/vm-107-disk-1.raw,size=7G
  609. ----
  610. The configuration files are simple text files. You can edit them using a normal
  611. text editor, for example, `vi` or `nano`.
  612. This is sometimes useful to do small corrections, but keep in mind that you
  613. need to restart the container to apply such changes.
  614. For that reason, it is usually better to use the `pct` command to generate and
  615. modify those files, or do the whole thing using the GUI.
  616. Our toolkit is smart enough to instantaneously apply most changes to running
  617. containers. This feature is called ``hot plug'', and there is no need to restart
  618. the container in that case.
  619. In cases where a change cannot be hot-plugged, it will be registered as a
  620. pending change (shown in red color in the GUI).
  621. They will only be applied after rebooting the container.
  622. File Format
  623. ~~~~~~~~~~~
  624. The container configuration file uses a simple colon separated key/value
  625. format. Each line has the following format:
  626. -----
  627. # this is a comment
  628. OPTION: value
  629. -----
  630. Blank lines in those files are ignored, and lines starting with a `#` character
  631. are treated as comments and are also ignored.
  632. It is possible to add low-level, LXC style configuration directly, for example:
  633. ----
  634. lxc.init_cmd: /sbin/my_own_init
  635. ----
  636. or
  637. ----
  638. lxc.init_cmd = /sbin/my_own_init
  639. ----
  640. The settings are passed directly to the LXC low-level tools.
  641. [[pct_snapshots]]
  642. Snapshots
  643. ~~~~~~~~~
  644. When you create a snapshot, `pct` stores the configuration at snapshot time
  645. into a separate snapshot section within the same configuration file. For
  646. example, after creating a snapshot called ``testsnapshot'', your configuration
  647. file will look like this:
  648. .Container configuration with snapshot
  649. ----
  650. memory: 512
  651. swap: 512
  652. parent: testsnaphot
  653. ...
  654. [testsnaphot]
  655. memory: 512
  656. swap: 512
  657. snaptime: 1457170803
  658. ...
  659. ----
  660. There are a few snapshot related properties like `parent` and `snaptime`. The
  661. `parent` property is used to store the parent/child relationship between
  662. snapshots. `snaptime` is the snapshot creation time stamp (Unix epoch).
  663. [[pct_options]]
  664. Options
  665. ~~~~~~~
  666. include::pct.conf.5-opts.adoc[]
  667. Locks
  668. -----
  669. Container migrations, snapshots and backups (`vzdump`) set a lock to prevent
  670. incompatible concurrent actions on the affected container. Sometimes you need
  671. to remove such a lock manually (e.g., after a power failure).
  672. ----
  673. # pct unlock <CTID>
  674. ----
  675. CAUTION: Only do this if you are sure the action which set the lock is no
  676. longer running.
  677. ifdef::manvolnum[]
  678. Files
  679. ------
  680. `/etc/pve/lxc/<CTID>.conf`::
  681. Configuration file for the container '<CTID>'.
  682. include::pve-copyright.adoc[]
  683. endif::manvolnum[]