+[[chapter_pct]]
ifdef::manvolnum[]
-PVE({manvolnum})
-================
-include::attributes.txt[]
+pct(1)
+======
+:pve-toplevel:
NAME
----
pct - Tool to manage Linux Containers (LXC) on Proxmox VE
-SYNOPSYS
+SYNOPSIS
--------
include::pct.1-synopsis.adoc[]
ifndef::manvolnum[]
Proxmox Container Toolkit
=========================
-include::attributes.txt[]
+:pve-toplevel:
endif::manvolnum[]
-
+ifdef::wiki[]
+:title: Linux Container
+endif::wiki[]
Containers are a lightweight alternative to fully virtualized
VMs. Instead of emulating a complete Operating System (OS), containers
VM, but without the additional overhead. We call this "System
Containers".
-NOTE: If you want to run micro-containers (with docker, rct, ...), it
+NOTE: If you want to run micro-containers (with docker, rkt, ...), it
is best to run them inside a VM.
-Security Considerations
------------------------
-
-Containers use the same kernel as the host, so there is a big attack
-surface for malicious users. You should consider this fact if you
-provide containers to totally untrusted people. In general, fully
-virtualized VMs provide better isolation.
-
-The good news is that LXC uses many kernel security features like
-AppArmor, CGroups and PID and user namespaces, which makes containers
-usage quite secure. We distinguish two types of containers:
-
-Privileged containers
-~~~~~~~~~~~~~~~~~~~~~
-
-Security is done by dropping capabilities, using mandatory access
-control (AppArmor), SecComp filters and namespaces. The LXC team
-considers this kind of container as unsafe, and they will not consider
-new container escape exploits to be security issues worthy of a CVE
-and quick fix. So you should use this kind of containers only inside a
-trusted environment, or when no untrusted task is running as root in
-the container.
-
-Unprivileged containers
-~~~~~~~~~~~~~~~~~~~~~~~
-
-This kind of containers use a new kernel feature called user
-namespaces. The root uid 0 inside the container is mapped to an
-unprivileged user outside the container. This means that most security
-issues (container escape, resource abuse, ...) in those containers
-will affect a random unprivileged user, and so would be a generic
-kernel security bug rather than an LXC issue. The LXC team thinks
-unprivileged containers are safe by design.
-
-
-Configuration
--------------
-
-The '/etc/pve/lxc/<CTID>.conf' files stores container configuration,
-where '<CTID>' is the numeric ID of the given container. Note that
-CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
-unique cluster wide. Files are stored inside '/etc/pve/', so they get
-automatically replicated to all other cluster nodes.
-
-.Example Container Configuration
-----
-ostype: debian
-arch: amd64
-hostname: www
-memory: 512
-swap: 512
-net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
-rootfs: local:107/vm-107-disk-1.raw,size=7G
-----
-
-Those configuration files are simple text files, and you can edit them
-using a normal text editor ('vi', 'nano', ...). This is sometimes
-useful to do small corrections, but keep in mind that you need to
-restart the container to apply such changes.
+Technology Overview
+-------------------
-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.
+* LXC (https://linuxcontainers.org/)
-File Format
-~~~~~~~~~~~
+* Integrated into {pve} graphical user interface (GUI)
-Container configuration files use a simple colon separated key/value
-format. Each line has the following format:
+* Easy to use command line tool `pct`
- # this is a comment
- OPTION: value
+* Access via {pve} REST API
-Blank lines in those files are ignored, and lines starting with a '#'
-character are treated as comments and are also ignored.
+* lxcfs to provide containerized /proc file system
-It is possible to add low-level, LXC style configuration directly, for
-example:
+* AppArmor/Seccomp to improve security
- lxc.init_cmd: /sbin/my_own_init
+* CRIU: for live migration (planned)
-or
+* Runs on modern Linux kernels
- lxc.init_cmd = /sbin/my_own_init
+* Image based deployment (templates)
-Those settings are directly passed to the LXC low-level tools.
+* Use {pve} storage library
-Snapshots
-~~~~~~~~~
+* Container setup from host (network, DNS, storage, ...)
-When you create a snapshot, 'pct' stores the configuration at snapshot
-time into a separate snapshot section within the same configuration
-file. For example, after creating a snapshot called 'testsnapshot',
-your configuration file will look like this:
-.Container Configuration with Snapshot
-----
-memory: 512
-swap: 512
-parent: testsnaphot
-...
+Security Considerations
+-----------------------
-[testsnaphot]
-memory: 512
-swap: 512
-snaptime: 1457170803
-...
-----
+Containers use the same kernel as the host, so there is a big attack
+surface for malicious users. You should consider this fact if you
+provide containers to totally untrusted people. In general, fully
+virtualized VMs provide better isolation.
-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).
+The good news is that LXC uses many kernel security features like
+AppArmor, CGroups and PID and user namespaces, which makes containers
+usage quite secure.
Guest Operating System Configuration
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+------------------------------------
We normally try to detect the operating system type inside the
container, and then modify some files inside the container to make
randomize crontab:: so that cron does not start at the same time on all containers
-The above task depends on the OS type, so the implementation is different
-for each OS type. You can also disable any modifications by manually
-setting the 'ostype' to 'unmanaged'.
+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:
-Ubuntu:: inspect /etc/lsb-release ('DISTRIB_ID=Ubuntu')
+Ubuntu:: inspect /etc/lsb-release (`DISTRIB_ID=Ubuntu`)
Debian:: test /etc/debian_version
Alpine:: test /etc/alpine-release
-NOTE: Container start fails if the configured 'ostype' differs from the auto
+Gentoo:: test /etc/gentoo-release
+
+NOTE: Container start fails if the configured `ostype` differs from the auto
detected type.
+[[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 images, sometimes also referred to as ``templates'' or
+``appliances'', are `tar` archives which contain everything to run a
container. You can think of it as a tidy container backup. Like most
-modern container toolkits, 'pct' uses those images when you create a
+modern container toolkits, `pct` uses those images when you create a
new container, for example:
pct create 999 local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz
-Proxmox itself ships a set of basic templates for most common
-operating systems, and you can download them using the 'pveam' (short
+{pve} itself ships a set of basic templates for most common
+operating systems, and you can download them using the `pveam` (short
for {pve} Appliance Manager) command line utility. You can also
download https://www.turnkeylinux.org/[TurnKey Linux] containers using
that tool (or the graphical user interface).
pveam available
-You can restrict this large list by specifying the 'section' you are
-interested in, for example basic 'system' images:
+You can restrict this large list by specifying the `section` you are
+interested in, for example basic `system` images:
.List available system images
----
----
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
+of your storages. You can simply use storage `local` for that
purpose. For clustered installations, it is preferred to use a shared
storage so that all nodes can access those images.
pveam download local debian-8.0-standard_8.0-1_amd64.tar.gz
You are now ready to create containers using that image, and you can
-list all downloaded images on storage 'local' with:
+list all downloaded images on storage `local` with:
----
# pveam list local
The above command shows you the full {pve} volume identifiers. They include
the storage name, and most other {pve} commands can use them. For
-examply you can delete that image later with:
+example you can delete that image later with:
pveam remove local:vztmpl/debian-8.0-standard_8.0-1_amd64.tar.gz
+[[pct_container_storage]]
Container Storage
-----------------
Traditional containers use a very simple storage model, only allowing
a single mount point, the root file system. This was further
-restricted to specific file system types like 'ext4' and 'nfs'.
-Additional mounts are often done by user provided scripts. This turend
+restricted to specific file system types like `ext4` and `nfs`.
+Additional mounts are often done by user provided scripts. This turned
out to be complex and error prone, so we try to avoid that now.
Our new LXC based container model is more flexible regarding
example, you can use a relatively slow (and thus cheap) storage for
the container root file system. Then you can use a second mount point
to mount a very fast, distributed storage for your database
-application.
+application. See section <<pct_mount_points,Mount Points>> for further
+details.
The second big improvement is that you can use any storage type
supported by the {pve} storage library. That means that you can store
-your containers on local 'lvmthin' or 'zfs', shared 'iSCSI' storage,
-or even on distributed storage systems like 'ceph'. It also enables us
-to use advanced storage features like snapshots and clones. 'vzdump'
+your containers on local `lvmthin` or `zfs`, shared `iSCSI` storage,
+or even on distributed storage systems like `ceph`. It also enables us
+to use advanced storage features like snapshots and clones. `vzdump`
can also use the snapshot feature to provide consistent container
backups.
also provide an easy way to share data between different containers.
-Managing Containers with 'pct'
+FUSE Mounts
+~~~~~~~~~~~
+
+WARNING: Because of existing issues in the Linux kernel's freezer
+subsystem the usage of FUSE mounts inside a container is strongly
+advised against, as containers need to be frozen for suspend or
+snapshot mode backups.
+
+If FUSE mounts cannot be replaced by other mounting mechanisms or storage
+technologies, it is possible to establish the FUSE mount on the Proxmox host
+and use a bind mount point to make it accessible inside the container.
+
+
+Using Quotas Inside Containers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Quotas allow to set limits inside a container for the amount of disk
+space that each user can use. This only works on ext4 image based
+storage types and currently does not work with unprivileged
+containers.
+
+Activating the `quota` option causes the following mount options to be
+used for a mount point:
+`usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0`
+
+This allows quotas to be used like you would on any other system. You
+can initialize the `/aquota.user` and `/aquota.group` files by running
+
+----
+quotacheck -cmug /
+quotaon /
+----
+
+and edit the quotas via the `edquota` command. Refer to the documentation
+of the distribution running inside the container for details.
+
+NOTE: You need to run the above commands for every mount point by passing
+the mount point's path instead of just `/`.
+
+
+Using ACLs Inside Containers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The standard Posix **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 Containers mount points
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+By default additional mount points besides the Root Disk mount point are not
+included in backups. You can reverse this default behavior by setting the
+*Backup* option on a mount point.
+// see PVE::VZDump::LXC::prepare()
+
+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 when starting a replication job, you can set the
+*Skip replication* option on that mount point. +
+As of {pve} 5.0, replication requires a storage of type `zfspool`, so adding a
+ mount point to a different type of storage when the container has replication
+ configured requires to *Skip replication* for that mount point.
+
+
+[[pct_settings]]
+Container Settings
+------------------
+
+[[pct_general]]
+General Settings
+~~~~~~~~~~~~~~~~
+
+[thumbnail="screenshot/gui-create-ct-general.png"]
+
+General settings of a container include
+
+* the *Node* : the physical server on which the container will run
+* the *CT ID*: a unique number in this {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.
+
+
+Privileged Containers
+^^^^^^^^^^^^^^^^^^^^^
+
+Security is done by dropping capabilities, using mandatory access
+control (AppArmor), SecComp filters and namespaces. The LXC team
+considers this kind of container as unsafe, and they will not consider
+new container escape exploits to be security issues worthy of a CVE
+and quick fix. So you should use this kind of containers only inside a
+trusted environment, or when no untrusted task is running as root in
+the container.
+
+
+Unprivileged Containers
+^^^^^^^^^^^^^^^^^^^^^^^
+
+This kind of containers use a new kernel feature called user
+namespaces. The root UID 0 inside the container is mapped to an
+unprivileged user outside the container. This means that most security
+issues (container escape, resource abuse, ...) in those containers
+will affect a random unprivileged user, and so would be a generic
+kernel security bug rather than an LXC issue. The LXC team thinks
+unprivileged containers are safe by design.
+
+NOTE: If the container uses systemd as an init system, please be
+aware the systemd version running inside the container should be equal
+or greater than 220.
+
+[[pct_cpu]]
+CPU
+~~~
+
+[thumbnail="screenshot/gui-create-ct-cpu.png"]
+
+You can restrict the number of visible CPUs inside the container using
+the `cores` option. This is implemented using the Linux 'cpuset'
+cgroup (**c**ontrol *group*). A special task inside `pvestatd` tries
+to distribute running containers among available CPUs. You can view
+the assigned CPUs using the following command:
+
+----
+# pct cpusets
+ ---------------------
+ 102: 6 7
+ 105: 2 3 4 5
+ 108: 0 1
+ ---------------------
+----
+
+Containers use the host kernel directly, so all task inside a
+container are handled by the host CPU scheduler. {pve} uses the Linux
+'CFS' (**C**ompletely **F**air **S**cheduler) scheduler by default,
+which has additional bandwidth control options.
+
+[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.
++
+----
+cores: 2
+cpulimit: 0.5
+----
+
+`cpuunits`: :: This is a relative weight passed to the kernel
+scheduler. The larger the number is, the more CPU time this container
+gets. Number is relative to the weights of all the other running
+containers. The default is 1024. You can use this setting to
+prioritize some containers.
+
+
+[[pct_memory]]
+Memory
+~~~~~~
+
+[thumbnail="screenshot/gui-create-ct-memory.png"]
+
+Container memory is controlled using the cgroup memory controller.
+
+[horizontal]
+
+`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`).
+
+
+[[pct_mount_points]]
+Mount Points
+~~~~~~~~~~~~
+
+[thumbnail="screenshot/gui-create-ct-root-disk.png"]
+
+The root mount point is configured with the `rootfs` property, and you can
+configure up to 10 additional mount points. The corresponding options
+are called `mp0` to `mp9`, and they can contain the following setting:
+
+include::pct-mountpoint-opts.adoc[]
+
+Currently there are basically three types of mount points: storage backed
+mount points, bind mounts and device mounts.
+
+.Typical container `rootfs` configuration
+----
+rootfs: thin1:base-100-disk-1,size=8G
+----
+
+
+Storage Backed Mount Points
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Storage backed mount points are managed by the {pve} storage subsystem and come
+in three different flavors:
+
+- Image based: these are raw images containing a single ext4 formatted file
+ system.
+- ZFS subvolumes: these are technically bind mounts, but with managed storage,
+ and thus allow resizing and snapshotting.
+- Directories: passing `size=0` triggers a special case where instead of a raw
+ image a directory is created.
+
+NOTE: The special option syntax `STORAGE_ID:SIZE_IN_GB` for storage backed
+mount point volumes will automatically allocate a volume of the specified size
+on the specified storage. E.g., calling
+`pct set 100 -mp0 thin1:10,mp=/path/in/container` will allocate a 10GB volume
+on the storage `thin1` and replace the volume ID place holder `10` with the
+allocated volume ID.
+
+
+Bind Mount Points
+^^^^^^^^^^^^^^^^^
+
+Bind mounts allow you to access arbitrary directories from your Proxmox VE host
+inside a container. Some potential use cases are:
+
+- Accessing your home directory in the guest
+- Accessing an USB device directory in the guest
+- Accessing an NFS mount from the host in the guest
+
+Bind mounts are considered to not be managed by the storage subsystem, so you
+cannot make snapshots or deal with quotas from inside the container. With
+unprivileged containers you might run into permission problems caused by the
+user mapping and cannot use ACLs.
+
+NOTE: The contents of bind mount points are not backed up when using `vzdump`.
+
+WARNING: For security reasons, bind mounts should only be established
+using source directories especially reserved for this purpose, e.g., a
+directory hierarchy under `/mnt/bindmounts`. Never bind mount system
+directories like `/`, `/var` or `/etc` into a container - this poses a
+great security risk.
+
+NOTE: The bind mount source path must not contain any symlinks.
+
+For example, to make the directory `/mnt/bindmounts/shared` accessible in the
+container with ID `100` under the path `/shared`, use a configuration line like
+`mp0: /mnt/bindmounts/shared,mp=/shared` in `/etc/pve/lxc/100.conf`.
+Alternatively, use `pct set 100 -mp0 /mnt/bindmounts/shared,mp=/shared` to
+achieve the same result.
+
+
+Device Mount Points
+^^^^^^^^^^^^^^^^^^^
+
+Device mount points allow to mount block devices of the host directly into the
+container. Similar to bind mounts, device mounts are not managed by {PVE}'s
+storage subsystem, but the `quota` and `acl` options will be honored.
+
+NOTE: Device mount points should only be used under special circumstances. In
+most cases a storage backed mount point offers the same performance and a lot
+more features.
+
+NOTE: The contents of device mount points are not backed up when using `vzdump`.
+
+
+[[pct_container_network]]
+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:
+
+include::pct-network-opts.adoc[]
+
+
+[[pct_startup_and_shutdown]]
+Automatic Start and Shutdown of Containers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+After creating your containers, you probably want them to start automatically
+when the host system boots. For this you need to select the option 'Start at
+boot' from the 'Options' Tab of your container in the web interface, or set it with
+the following command:
+
+ pct set <ctid> -onboot 1
+
+.Start and Shutdown Order
+// 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 :
+
+* *Start/Shutdown order*: Defines the start order priority. E.g. set it to 1 if
+you want the CT to be the first to be started. (We use the reverse startup
+order for shutdown, so a container with a start order of 1 would be the last to
+be shut down)
+* *Startup delay*: Defines the interval between this container start and subsequent
+containers starts . E.g. set it to 240 if you want to wait 240 seconds before starting
+other containers.
+* *Shutdown timeout*: Defines the duration in seconds {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.
+
+Please note that containers without a Start/Shutdown order parameter will always
+start after those where the parameter is set, and this parameter only
+makes sense between the machines running locally on a host, and not
+cluster-wide.
+
+Hookscripts
+~~~~~~~~~~~
+
+You can add a hook script to CTs with the config property `hookscript`.
+
+ pct set 100 -hookscript local:snippets/hookscript.pl
+
+It will be called during various phases of the guests lifetime.
+For an example and documentation see the example script under
+`/usr/share/pve-docs/examples/guest-example-hookscript.pl`.
+
+Backup and Restore
+------------------
+
+
+Container Backup
+~~~~~~~~~~~~~~~~
+
+It is possible to use the `vzdump` tool for container backup. Please
+refer to the `vzdump` manual page for details.
+
+
+Restoring Container Backups
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Restoring container backups made with `vzdump` is possible using the
+`pct restore` command. By default, `pct restore` will attempt to restore as much
+of the backed up container configuration as possible. It is possible to override
+the backed up configuration by manually setting container options on the command
+line (see the `pct` manual page for details).
+
+NOTE: `pvesm extractconfig` can be used to view the backed up configuration
+contained in a vzdump archive.
+
+There are two basic restore modes, only differing by their handling of mount
+points:
+
+
+``Simple'' Restore Mode
+^^^^^^^^^^^^^^^^^^^^^^^
+
+If neither the `rootfs` parameter nor any of the optional `mpX` parameters
+are explicitly set, the mount point configuration from the backed up
+configuration file is restored using the following steps:
+
+. Extract mount points and their options from backup
+. Create volumes for storage backed mount points (on storage provided with the
+`storage` parameter, or default local storage if unset)
+. Extract files from backup archive
+. Add bind and device mount points to restored configuration (limited to root user)
+
+NOTE: Since bind and device mount points are never backed up, no files are
+restored in the last step, but only the configuration options. The assumption
+is that such mount points are either backed up with another mechanism (e.g.,
+NFS space that is bind mounted into many containers), or not intended to be
+backed up at all.
+
+This simple mode is also used by the container restore operations in the web
+interface.
+
+
+``Advanced'' Restore Mode
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+By setting the `rootfs` parameter (and optionally, any combination of `mpX`
+parameters), the `pct restore` command is automatically switched into an
+advanced mode. This advanced mode completely ignores the `rootfs` and `mpX`
+configuration options contained in the backup archive, and instead only
+uses the options explicitly provided as parameters.
+
+This mode allows flexible configuration of mount point settings at restore time,
+for example:
+
+* Set target storages, volume sizes and other options for each mount point
+individually
+* Redistribute backed up files according to new mount point scheme
+* Restore to device and/or bind mount points (limited to root user)
+
+
+Managing Containers with `pct`
------------------------------
-'pct' is the tool to manage Linux Containers on {pve}. You can create
+`pct` is the tool to manage Linux Containers on {pve}. You can create
and destroy containers, and control execution (start, stop, migrate,
...). You can use pct to set parameters in the associated config file,
like network configuration or memory limits.
+
CLI Usage Examples
-------------------
+~~~~~~~~~~~~~~~~~~
Create a container based on a Debian template (provided you have
-already downloaded the template via the webgui)
+already downloaded the template via the web interface)
pct create 100 /var/lib/vz/template/cache/debian-8.0-standard_8.0-1_amd64.tar.gz
pct config 100
-Add a network interface called eth0, bridged to the host bridge vmbr0,
+Add a network interface called `eth0`, bridged to the host bridge `vmbr0`,
set the address and gateway, while it's running
pct set 100 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.147/24,gw=192.168.15.1
Reduce the memory of the container to 512MB
- pct set -memory 512 100
+ pct set 100 -memory 512
-Files
-------
-'/etc/pve/lxc/<CTID>.conf'::
+Obtaining Debugging Logs
+~~~~~~~~~~~~~~~~~~~~~~~~
-Configuration file for the container '<CTID>'.
+In case `pct start` is unable to start a specific container, it might be
+helpful to collect debugging output by running `lxc-start` (replace `ID` with
+the container's ID):
+ lxc-start -n ID -F -l DEBUG -o /tmp/lxc-ID.log
-Container Advantages
---------------------
+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.
-- Simple, and fully integrated into {pve}. Setup looks similar to a normal
- VM setup.
+The collected debug log is written to `/tmp/lxc-ID.log`.
- * Storage (ZFS, LVM, NFS, Ceph, ...)
+NOTE: If you have changed the container's configuration since the last start
+attempt with `pct start`, you need to run `pct start` at least once to also
+update the configuration used by `lxc-start`.
- * Network
+[[pct_migration]]
+Migration
+---------
- * Authentification
+If you have a cluster, you can migrate your Containers with
- * Cluster
+ pct migrate <vmid> <target>
-- Fast: minimal overhead, as fast as bare metal
+This works as long as your Container is offline. If it has local volumes or
+mountpoints defined, the migration will copy the content over the network to
+the target host if there is the same storage defined.
-- High density (perfect for idle workloads)
+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.
-- REST API
+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.
-- Direct hardware access
+[[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.
-Technology Overview
--------------------
+NOTE: CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
+unique cluster wide.
-- Integrated into {pve} graphical user interface (GUI)
+.Example Container Configuration
+----
+ostype: debian
+arch: amd64
+hostname: www
+memory: 512
+swap: 512
+net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
+rootfs: local:107/vm-107-disk-1.raw,size=7G
+----
-- LXC (https://linuxcontainers.org/)
+Those configuration files are simple text files, and you can edit them
+using a normal text editor (`vi`, `nano`, ...). This is sometimes
+useful to do small corrections, but keep in mind that you need to
+restart the container to apply such changes.
-- cgmanager for cgroup management
+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.
-- lxcfs to provive containerized /proc file system
-- apparmor
+File Format
+~~~~~~~~~~~
-- CRIU: for live migration (planned)
+Container configuration files use a simple colon separated key/value
+format. Each line has the following format:
-- We use latest available kernels (4.2.X)
+-----
+# this is a comment
+OPTION: value
+-----
-- Image based deployment (templates)
+Blank lines in those files are ignored, and lines starting with a `#`
+character are treated as comments and are also ignored.
-- Container setup from host (Network, DNS, Storage, ...)
+It is possible to add low-level, LXC style configuration directly, for
+example:
+
+ lxc.init_cmd: /sbin/my_own_init
+
+or
+
+ lxc.init_cmd = /sbin/my_own_init
+
+Those settings are directly passed to the LXC low-level tools.
+
+
+[[pct_snapshots]]
+Snapshots
+~~~~~~~~~
+
+When you create a snapshot, `pct` stores the configuration at snapshot
+time into a separate snapshot section within the same configuration
+file. For example, after creating a snapshot called ``testsnapshot'',
+your configuration file will look like this:
+
+.Container configuration with snapshot
+----
+memory: 512
+swap: 512
+parent: testsnaphot
+...
+
+[testsnaphot]
+memory: 512
+swap: 512
+snaptime: 1457170803
+...
+----
+
+There are a few snapshot related properties like `parent` and
+`snaptime`. The `parent` property is used to store the parent/child
+relationship between snapshots. `snaptime` is the snapshot creation
+time stamp (Unix epoch).
+
+
+[[pct_options]]
+Options
+~~~~~~~
+
+include::pct.conf.5-opts.adoc[]
+
+
+Locks
+-----
+
+Container migrations, snapshots and backups (`vzdump`) set a lock to
+prevent incompatible concurrent actions on the affected container. Sometimes
+you need to remove such a lock manually (e.g., after a power failure).
+
+ pct unlock <CTID>
+
+CAUTION: Only do that if you are sure the action which set the lock is
+no longer running.
ifdef::manvolnum[]
+
+Files
+------
+
+`/etc/pve/lxc/<CTID>.conf`::
+
+Configuration file for the container '<CTID>'.
+
+
include::pve-copyright.adoc[]
endif::manvolnum[]
projects / pve-docs.git / blobdiff