+[[chapter_pct]]
ifdef::manvolnum[]
-PVE({manvolnum})
-================
+pct(1)
+======
include::attributes.txt[]
+:pve-toplevel:
NAME
----
pct - Tool to manage Linux Containers (LXC) on Proxmox VE
-SYNOPSYS
+SYNOPSIS
--------
include::pct.1-synopsis.adoc[]
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
is best to run them inside a VM.
+Technology Overview
+-------------------
+
+* LXC (https://linuxcontainers.org/)
+
+* Integrated into {pve} graphical user interface (GUI)
+
+* Easy to use command line tool `pct`
+
+* Access via {pve} REST API
+
+* lxcfs to provide containerized /proc file system
+
+* AppArmor/Seccomp to improve security
+
+* CRIU: for live migration (planned)
+
+* Use latest available kernels (4.4.X)
+
+* Image based deployment (templates)
+
+* Use {pve} storage library
+
+* Container setup from host (network, DNS, storage, ...)
+
+
Security Considerations
-----------------------
AppArmor, CGroups and PID and user namespaces, which makes containers
usage quite secure. We distinguish two types of containers:
-Privileged containers
+
+Privileged Containers
~~~~~~~~~~~~~~~~~~~~~
Security is done by dropping capabilities, using mandatory access
trusted environment, or when no untrusted task is running as root in
the container.
-Unprivileged containers
+
+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
+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
unprivileged containers are safe by design.
-Configuration
--------------
-
-The '/etc/pve/lxc/<CTID>.conf' file stores container configuration,
-where '<CTID>' is the numeric ID of the given container. Like all
-other files stored inside '/etc/pve/', they get automatically
-replicated to all other cluster nodes.
-
-NOTE: CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
-unique cluster wide.
-
-.Example Container Configuration
-----
-ostype: debian
-arch: amd64
-hostname: www
-memory: 512
-swap: 512
-net0: bridge=vmbr0,hwaddr=66:64:66:64:64:36,ip=dhcp,name=eth0,type=veth
-rootfs: local:107/vm-107-disk-1.raw,size=7G
-----
-
-Those configuration files are simple text files, and you can edit them
-using a normal text editor ('vi', 'nano', ...). This is sometimes
-useful to do small corrections, but keep in mind that you need to
-restart the container to apply such changes.
-
-For that reason, it is usually better to use the 'pct' command to
-generate and modify those files, or do the whole thing using the GUI.
-Our toolkit is smart enough to instantaneously apply most changes to
-running containers. This feature is called "hot plug", and there is no
-need to restart the container in that case.
-
-File Format
-~~~~~~~~~~~
-
-Container configuration files use a simple colon separated key/value
-format. Each line has the following format:
-
- # this is a comment
- OPTION: value
-
-Blank lines in those files are ignored, and lines starting with a '#'
-character are treated as comments and are also ignored.
-
-It is possible to add low-level, LXC style configuration directly, for
-example:
-
- lxc.init_cmd: /sbin/my_own_init
-
-or
-
- lxc.init_cmd = /sbin/my_own_init
-
-Those settings are directly passed to the LXC low-level tools.
-
-Snapshots
-~~~~~~~~~
-
-When you create a snapshot, 'pct' stores the configuration at snapshot
-time into a separate snapshot section within the same configuration
-file. For example, after creating a snapshot called 'testsnapshot',
-your configuration file will look like this:
-
-.Container Configuration with Snapshot
-----
-memory: 512
-swap: 512
-parent: testsnaphot
-...
-
-[testsnaphot]
-memory: 512
-swap: 512
-snaptime: 1457170803
-...
-----
-
-There are a few snapshot related properties like 'parent' and
-'snaptime'. The 'parent' property is used to store the parent/child
-relationship between snapshots. 'snaptime' is the snapshot creation
-time stamp (unix epoch).
-
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
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'.
+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
Gentoo:: test /etc/gentoo-release
-NOTE: Container start fails if the configured 'ostype' differs from the auto
+NOTE: Container start fails if the configured `ostype` differs from the auto
detected type.
-Options
-~~~~~~~
-
-include::pct.conf.5-opts.adoc[]
-
+[[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
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.
Currently there are basically three types of mount points: storage backed
mount points, bind mounts and device mounts.
-.Typical Container `rootfs` configuration
+.Typical container `rootfs` configuration
----
rootfs: thin1:base-100-disk-1,size=8G
----
-Storage backed mount points
+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
+- Image based: these are raw images containing a single ext4 formatted file
system.
-- ZFS Subvolumes: These are technically bind mounts, but with managed storage,
+- 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.
-Bind mount points
+Bind Mount Points
^^^^^^^^^^^^^^^^^
Bind mounts allow you to access arbitrary directories from your Proxmox VE host
- Accessing your home directory in the guest
- Accessing an USB device directory in the guest
-- Accessing an NFS mount from in the host 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'.
+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
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
+`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
^^^^^^^^^^^^^^^^^^^
Device mount points allow to mount block devices of the host directly into the
most cases a storage backed mount point offers the same performance and a lot
more features.
-NOTE: The contents of device mount points are not backed up when using 'vzdump'.
+NOTE: The contents of device mount points are not backed up when using `vzdump`.
-FUSE mounts
+FUSE Mounts
~~~~~~~~~~~
WARNING: Because of existing issues in the Linux kernel's freezer
and use a bind mount point to make it accessible inside the container.
-Using quotas inside containers
+Using Quotas Inside Containers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Quotas allow to set limits inside a container for the amount of disk
the mount point's path instead of just `/`.
-Using ACLs inside containers
+Using ACLs Inside Containers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The standard Posix Access Control Lists are also available 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.
+[[pct_container_network]]
Container Network
-----------------
You can configure up to 10 network interfaces for a single
-container. The corresponding options are called 'net0' to 'net9', and
+container. The corresponding options are called `net0` to `net9`, and
they can contain the following setting:
include::pct-network-opts.adoc[]
Backup and Restore
------------------
+
Container Backup
~~~~~~~~~~~~~~~~
-It is possible to use the 'vzdump' tool for container backup. Please
-refer to the 'vzdump' manual page for details.
+It is possible to use the `vzdump` tool for container backup. Please
+refer to the `vzdump` manual page for details.
+
Restoring Container Backups
~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Restoring container backups made with 'vzdump' is possible using the
-'pct restore' command. By default, 'pct restore' will attempt to restore as much
+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).
+line (see the `pct` manual page for details).
-NOTE: 'pvesm extractconfig' can be used to view the backed up configuration
+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
-^^^^^^^^^^^^^^^^^^^^^
+``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
interface.
-"Advanced" restore mode
-^^^^^^^^^^^^^^^^^^^^^^^
+``Advanced'' Restore Mode
+^^^^^^^^^^^^^^^^^^^^^^^^^
By setting the `rootfs` parameter (and optionally, any combination of `mpX`
-parameters), the 'pct restore' command is automatically switched into an
+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.
* Restore to device and/or bind mount points (limited to root user)
-Managing Containers with 'pct'
+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
pct set 100 -memory 512
-Files
-------
+Obtaining Debugging Logs
+~~~~~~~~~~~~~~~~~~~~~~~~
-'/etc/pve/lxc/<CTID>.conf'::
+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):
-Configuration file for the container '<CTID>'.
+ lxc-start -n ID -F -l DEBUG -o /tmp/lxc-ID.log
+This command will attempt to start the container in foreground mode, to stop the container run `pct shutdown ID` or `pct stop ID` in a second terminal.
-Container Advantages
---------------------
+The collected debug log is written to `/tmp/lxc-ID.log`.
-- Simple, and fully integrated into {pve}. Setup looks similar to a normal
- VM setup.
+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`.
- * Storage (ZFS, LVM, NFS, Ceph, ...)
- * Network
+[[pct_configuration]]
+Configuration
+-------------
- * Authentification
+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.
- * Cluster
+NOTE: CTIDs < 100 are reserved for internal purposes, and CTIDs need to be
+unique cluster wide.
-- Fast: minimal overhead, as fast as bare metal
+.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
+----
-- High density (perfect for idle workloads)
+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.
-- REST API
+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.
-- Direct hardware access
+File Format
+~~~~~~~~~~~
-Technology Overview
--------------------
+Container configuration files use a simple colon separated key/value
+format. Each line has the following format:
+
+-----
+# this is a comment
+OPTION: value
+-----
+
+Blank lines in those files are ignored, and lines starting with a `#`
+character are treated as comments and are also ignored.
-- Integrated into {pve} graphical user interface (GUI)
+It is possible to add low-level, LXC style configuration directly, for
+example:
-- LXC (https://linuxcontainers.org/)
+ lxc.init_cmd: /sbin/my_own_init
-- cgmanager for cgroup management
+or
-- lxcfs to provive containerized /proc file system
+ lxc.init_cmd = /sbin/my_own_init
-- apparmor
+Those settings are directly passed to the LXC low-level tools.
-- CRIU: for live migration (planned)
-- We use latest available kernels (4.4.X)
+[[pct_snapshots]]
+Snapshots
+~~~~~~~~~
-- Image based deployment (templates)
+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 setup from host (Network, DNS, Storage, ...)
+.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