# lxc.container.conf

## NAME



           lxc.container.conf - LXC container configuration file
    


## DESCRIPTION



           LXC is the well-known and heavily tested low-level Linux container
           runtime. It is in active development since 2008 and has proven
           itself in critical production environments world-wide. Some of its
           core contributors are the same people that helped to implement
           various well-known containerization features inside the Linux
           kernel.
    
           LXC's main focus is system containers. That is, containers which
           offer an environment as close as possible as the one you'd get
           from a VM but without the overhead that comes with running a
           separate kernel and simulating all the hardware.
    
           This is achieved through a combination of kernel security features
           such as namespaces, mandatory access control and control groups.
    
           LXC has support for unprivileged containers. Unprivileged
           containers are containers that are run without any privilege. This
           requires support for user namespaces in the kernel that the
           container is run on. LXC was the first runtime to support
           unprivileged containers after user namespaces were merged into the
           mainline kernel.
    
           In essence, user namespaces isolate given sets of UIDs and GIDs.
           This is achieved by establishing a mapping between a range of UIDs
           and GIDs on the host to a different (unprivileged) range of UIDs
           and GIDs in the container. The kernel will translate this mapping
           in such a way that inside the container all UIDs and GIDs appear
           as you would expect from the host whereas on the host these UIDs
           and GIDs are in fact unprivileged. For example, a process running
           as UID and GID 0 inside the container might appear as UID and GID
           100000 on the host. The implementation and working details can be
           gathered from the corresponding user namespace man page.  UID and
           GID mappings can be defined with the **lxc.idmap** key.
    
           Linux containers are defined with a simple configuration file.
           Each option in the configuration file has the form **key = value**
           fitting in one line. The "#" character means the line is a
           comment. List options, like capabilities and cgroups options, can
           be used with no value to clear any previously defined values of
           that option.
    
           LXC namespaces configuration keys use single dots. This means
           complex configuration keys such as **lxc.net.0** expose various
           subkeys such as **lxc.net.0.type** , **lxc.net.0.link** ,
           **lxc.net.0.ipv6.address** , and others for even more fine-grained
           configuration.
    
       **CONFIGURATION**
           In order to ease administration of multiple related containers, it
           is possible to have a container configuration file cause another
           file to be loaded. For instance, network configuration can be
           defined in one common file which is included by multiple
           containers. Then, if the containers are moved to another host,
           only one file may need to be updated.
    
           **lxc.include**
                  Specify the file to be included. The included file must be
                  in the same valid lxc configuration file format.
    
       **ARCHITECTURE**
           Allows one to set the architecture for the container. For example,
           set a 32bits architecture for a container running 32bits binaries
           on a 64bits host. This fixes the container scripts which rely on
           the architecture to do some work like downloading the packages.
    
           **lxc.arch**
                  Specify the architecture for the container.
    
                  Some valid options are **x86** , **i686** , **x86_64** , **amd64**
    
       **HOSTNAME**
           The utsname section defines the hostname to be set for the
           container.  That means the container can set its own hostname
           without changing the one from the system. That makes the hostname
           private for the container.
    
           **lxc.uts.name**
                  specify the hostname for the container
    
       **HALT SIGNAL**
           Allows one to specify signal name or number sent to the
           container's init process to cleanly shutdown the container.
           Different init systems could use different signals to perform
           clean shutdown sequence. This option allows the signal to be
           specified in kill(1) fashion, e.g.  SIGPWR, SIGRTMIN+14,
           SIGRTMAX-10 or plain number. The default signal is SIGPWR.
    
           **lxc.signal.halt**
                  specify the signal used to halt the container
    
       **REBOOT SIGNAL**
           Allows one to specify signal name or number to reboot the
           container.  This option allows signal to be specified in kill(1)
           fashion, e.g.  SIGTERM, SIGRTMIN+14, SIGRTMAX-10 or plain number.
           The default signal is SIGINT.
    
           **lxc.signal.reboot**
                  specify the signal used to reboot the container
    
       **STOP SIGNAL**
           Allows one to specify signal name or number to forcibly shutdown
           the container. This option allows signal to be specified in
           kill(1) fashion, e.g. SIGKILL, SIGRTMIN+14, SIGRTMAX-10 or plain
           number. The default signal is SIGKILL.
    
           **lxc.signal.stop**
                  specify the signal used to stop the container
    
       **INIT COMMAND**
           Sets the command to use as the init system for the containers.
    
           **lxc.execute.cmd**
                  Absolute path from container rootfs to the binary to run by
                  default. This mostly makes sense for **lxc-execute**.
    
           **lxc.init.cmd**
                  Absolute path from container rootfs to the binary to use as
                  init. This mostly makes sense for **lxc-start**. Default is
                  **/sbin/init**.
    
       **INIT WORKING DIRECTORY**
           Sets the absolute path inside the container as the working
           directory for the containers.  LXC will switch to this directory
           before executing init.
    
           **lxc.init.cwd**
                  Absolute path inside the container to use as the working
                  directory.
    
       **INIT ID**
           Sets the UID/GID to use for the init system, and subsequent
           commands.  Note that using a non-root UID when booting a system
           container will likely not work due to missing privileges. Setting
           the UID/GID is mostly useful when running application containers.
           Defaults to: UID(0), GID(0)
    
           **lxc.init.uid**
                  UID to use for init.
    
           **lxc.init.gid**
                  GID to use for init.
    
       **CORE SCHEDULING**
           Core scheduling defines if the container payload is marked as
           being schedulable on the same core. Doing so will cause the kernel
           scheduler to ensure that tasks that are not in the same group
           never run simultaneously on a core. This can serve as an extra
           security measure to prevent the container payload from using cross
           hyper thread attacks.
    
           **lxc.sched.core**
                  The only allowed values are 0 and 1. Set this to 1 to
                  create a core scheduling domain for the container or 0 to
                  not create one.  If not set explicitly no core scheduling
                  domain will be created for the container.
    
       **PROC**
           Configure proc filesystem for the container.
    
           **lxc.proc.[proc file name]**
                  Specify the proc file name to be set. The file names
                  available are those listed under /proc/PID/.  Example:
    
                                lxc.proc.oom_score_adj = 10
    
       **EPHEMERAL**
           Allows one to specify whether a container will be destroyed on
           shutdown.
    
           **lxc.ephemeral**
                  The only allowed values are 0 and 1. Set this to 1 to
                  destroy a container on shutdown.
    
       **NETWORK**
           The network section defines how the network is virtualized in the
           container. The network virtualization acts at layer two. In order
           to use the network virtualization, parameters must be specified to
           define the network interfaces of the container. Several virtual
           interfaces can be assigned and used in a container even if the
           system has only one physical network interface.
    
           **lxc.net**
                  may be used without a value to clear all previous network
                  options.
    
           **lxc.net.[i].type**
                  specify what kind of network virtualization to be used for
                  the container.  Must be specified before any other
                  option(s) on the net device.  Multiple networks can be
                  specified by using an additional index **i** after all
                  **lxc.net.*** keys. For example, **lxc.net.0.type = veth** and
                  **lxc.net.1.type = veth** specify two different networks of the
                  same type. All keys sharing the same index **i** will be
                  treated as belonging to the same network. For example,
                  **lxc.net.0.link = br0** will belong to **lxc.net.0.type**.
                  Currently, the different virtualization types can be:
    
                  **empty:** will create only the loopback interface.
    
                  **veth:** a virtual ethernet pair device is created with one
                  side assigned to the container and the other side on the
                  host.  **lxc.net.[i].veth.mode** specifies the mode the veth
                  parent will use on the host.  The accepted modes are **bridge**
                  and **router**.  The mode defaults to bridge if not specified.
                  In **bridge** mode the host side is attached to a bridge
                  specified by the **lxc.net.[i].link** option.  If the bridge
                  link is not specified, then the veth pair device will be
                  created but not attached to any bridge.  Otherwise, the
                  bridge has to be created on the system before starting the
                  container.  **lxc** won't handle any configuration outside of
                  the container.  In **router** mode static routes are created on
                  the host for the container's IP addresses pointing to the
                  host side veth interface.  Additionally Proxy ARP and Proxy
                  NDP entries are added on the host side veth interface for
                  the gateway IPs defined in the container to allow the
                  container to reach the host.  By default, **lxc** chooses a
                  name for the network device belonging to the outside of the
                  container, but if you wish to handle this name yourselves,
                  you can tell **lxc** to set a specific name with the
                  **lxc.net.[i].veth.pair** option (except for unprivileged
                  containers where this option is ignored for security
                  reasons).  Static routes can be added on the host pointing
                  to the container using the **lxc.net.[i].veth.ipv4.route** and
                  **lxc.net.[i].veth.ipv6.route** options.  Several lines specify
                  several routes.  The route is in format x.y.z.t/m, eg.
                  192.168.1.0/24.  In **bridge** mode untagged VLAN membership
                  can be set with the **lxc.net.[i].veth.vlan.id** option. It
                  accepts a special value of 'none' indicating that the
                  container port should be removed from the bridge's default
                  untagged VLAN.  The **lxc.net.[i].veth.vlan.tagged.id** option
                  can be specified multiple times to set the container's
                  bridge port membership to one or more tagged VLANs.
    
                  **vlan:** a vlan interface is linked with the interface
                  specified by the **lxc.net.[i].link** and assigned to the
                  container. The vlan identifier is specified with the option
                  **lxc.net.[i].vlan.id**.
    
                  **macvlan:** a macvlan interface is linked with the interface
                  specified by the **lxc.net.[i].link** and assigned to the
                  container.  **lxc.net.[i].macvlan.mode** specifies the mode the
                  macvlan will use to communicate between different macvlan
                  on the same upper device. The accepted modes are **private** ,
                  **vepa** , **bridge** and **passthru**.  In **private** mode, the device
                  never communicates with any other device on the same
                  upper_dev (default).  In **vepa** mode, the new Virtual
                  Ethernet Port Aggregator (VEPA) mode, it assumes that the
                  adjacent bridge returns all frames where both source and
                  destination are local to the macvlan port, i.e. the bridge
                  is set up as a reflective relay. Broadcast frames coming in
                  from the upper_dev get flooded to all macvlan interfaces in
                  VEPA mode, local frames are not delivered locally. In
                  **bridge** mode, it provides the behavior of a simple bridge
                  between different macvlan interfaces on the same port.
                  Frames from one interface to another one get delivered
                  directly and are not sent out externally. Broadcast frames
                  get flooded to all other bridge ports and to the external
                  interface, but when they come back from a reflective relay,
                  we don't deliver them again. Since we know all the MAC
                  addresses, the macvlan bridge mode does not require
                  learning or STP like the bridge module does. In **passthru**
                  mode, all frames received by the physical interface are
                  forwarded to the macvlan interface. Only one macvlan
                  interface in **passthru** mode is possible for one physical
                  interface.
    
                  **ipvlan:** an ipvlan interface is linked with the interface
                  specified by the **lxc.net.[i].link** and assigned to the
                  container.  **lxc.net.[i].ipvlan.mode** specifies the mode the
                  ipvlan will use to communicate between different ipvlan on
                  the same upper device. The accepted modes are **l3** , **l3s** and
                  **l2**. It defaults to **l3** mode.  In **l3** mode TX processing up to
                  L3 happens on the stack instance attached to the dependent
                  device and packets are switched to the stack instance of
                  the parent device for the L2 processing and routing from
                  that instance will be used before packets are queued on the
                  outbound device. In this mode the dependent devices will
                  not receive nor can send multicast / broadcast traffic.  In
                  **l3s** mode TX processing is very similar to the L3 mode
                  except that iptables (conn-tracking) works in this mode and
                  hence it is L3-symmetric (L3s).  This will have slightly
                  less performance but that shouldn't matter since you are
                  choosing this mode over plain-L3 mode to make conn-tracking
                  work.  In **l2** mode TX processing happens on the stack
                  instance attached to the dependent device and packets are
                  switched and queued to the parent device to send devices
                  out. In this mode the dependent devices will RX/TX
                  multicast and broadcast (if applicable) as well.
                  **lxc.net.[i].ipvlan.isolation** specifies the isolation mode.
                  The accepted isolation values are **bridge** , **private** and **vepa**.
                  It defaults to **bridge**.  In **bridge** isolation mode dependent
                  devices can cross-talk among themselves apart from talking
                  through the parent device.  In **private** isolation mode the
                  port is set in private mode.  i.e. port won't allow cross
                  communication between dependent devices.  In **vepa** isolation
                  mode the port is set in VEPA mode.  i.e. port will offload
                  switching functionality to the external entity as described
                  in 802.1Qbg.
    
                  **phys:** an already existing interface specified by the
                  **lxc.net.[i].link** is assigned to the container.
    
           **lxc.net.[i].flags**
                  Specify an action to do for the network.
    
                  **up:** activates the interface.
    
           **lxc.net.[i].link**
                  Specify the interface to be used for real network traffic.
    
           **lxc.net.[i].l2proxy**
                  Controls whether layer 2 IP neighbour proxy entries will be
                  added to the lxc.net.[i].link interface for the IP
                  addresses of the container.  Can be set to 0 or 1. Defaults
                  to 0.  When used with IPv4 addresses, the following sysctl
                  values need to be set: net.ipv4.conf.[link].forwarding=1
                  When used with IPv6 addresses, the following sysctl values
                  need to be set: net.ipv6.conf.[link].proxy_ndp=1
                  net.ipv6.conf.[link].forwarding=1
    
           **lxc.net.[i].mtu**
                  Specify the maximum transfer unit for this interface.
    
           **lxc.net.[i].name**
                  The interface name is dynamically allocated, but if another
                  name is needed because the configuration files being used
                  by the container use a generic name, eg. eth0, this option
                  will rename the interface in the container.
    
           **lxc.net.[i].hwaddr**
                  The interface mac address is dynamically allocated by
                  default to the virtual interface, but in some cases, this
                  is needed to resolve a mac address conflict or to always
                  have the same link-local ipv6 address. Any "x" in address
                  will be replaced by random value, this allows setting
                  hwaddr templates.
    
           **lxc.net.[i].ipv4.address**
                  Specify the ipv4 address to assign to the virtualized
                  interface.  Several lines specify several ipv4 addresses.
                  The address is in format x.y.z.t/m, eg. 192.168.1.123/24.
                  You can optionally specify the broadcast address after the
                  IP address, e.g. 192.168.1.123/24 255.255.255.255.
                  Otherwise it is automatically calculated from the IP
                  address.
    
           **lxc.net.[i].ipv4.gateway**
                  Specify the ipv4 address to use as the gateway inside the
                  container. The address is in format x.y.z.t, eg.
                  192.168.1.123.  Can also have the special value **auto** , which
                  means to take the primary address from the bridge interface
                  (as specified by the **lxc.net.[i].link** option) and use that
                  as the gateway. **auto** is only available when using the **veth** ,
                  **macvlan** and **ipvlan** network types.  Can also have the
                  special value of **dev** , which means to set the default
                  gateway as a device route.  This is primarily for use with
                  layer 3 network modes, such as IPVLAN.
    
           **lxc.net.[i].ipv6.address**
                  Specify the ipv6 address to assign to the virtualized
                  interface. Several lines specify several ipv6 addresses.
                  The address is in format x::y/m, eg.
                  2003:db8:1:0:214:1234:fe0b:3596/64
    
           **lxc.net.[i].ipv6.gateway**
                  Specify the ipv6 address to use as the gateway inside the
                  container. The address is in format x::y, eg.
                  2003:db8:1:0::1 Can also have the special value **auto** , which
                  means to take the primary address from the bridge interface
                  (as specified by the **lxc.net.[i].link** option) and use that
                  as the gateway. **auto** is only available when using the **veth** ,
                  **macvlan** and **ipvlan** network types.  Can also have the
                  special value of **dev** , which means to set the default
                  gateway as a device route.  This is primarily for use with
                  layer 3 network modes, such as IPVLAN.
    
           **lxc.net.[i].script.up**
                  Add a configuration option to specify a script to be
                  executed after creating and configuring the network used
                  from the host side.
    
                  In addition to the information available to all hooks. The
                  following information is provided to the script:
    
                  • LXC_HOOK_TYPE: the hook type. This is either 'up' or
                    'down'.
    
                  • LXC_HOOK_SECTION: the section type 'net'.
    
                  • LXC_NET_TYPE: the network type. This is one of the valid
                    network types listed here (e.g. 'vlan', 'macvlan',
                    'ipvlan', 'veth').
    
                  • LXC_NET_PARENT: the parent device on the host. This is
                    only set for network types 'mavclan', 'veth', 'phys'.
    
                  • LXC_NET_PEER: the name of the peer device on the host.
                    This is only set for 'veth' network types. Note that this
                    information is only available when **lxc.hook.version** is
                    set to 1.
    
           Whether this information is provided in the form of environment
           variables or as arguments to the script depends on the value of
           **lxc.hook.version**. If set to 1 then information is provided in the
           form of environment variables. If set to 0 information is provided
           as arguments to the script.
    
           Standard output from the script is logged at debug level.
           Standard error is not logged, but can be captured by the hook
           redirecting its standard error to standard output.
    
           **lxc.net.[i].script.down**
                  Add a configuration option to specify a script to be
                  executed before destroying the network used from the host
                  side.
    
                  In addition to the information available to all hooks. The
                  following information is provided to the script:
    
                  • LXC_HOOK_TYPE: the hook type. This is either 'up' or
                    'down'.
    
                  • LXC_HOOK_SECTION: the section type 'net'.
    
                  • LXC_NET_TYPE: the network type. This is one of the valid
                    network types listed here (e.g. 'vlan', 'macvlan',
                    'ipvlan', 'veth').
    
                  • LXC_NET_PARENT: the parent device on the host. This is
                    only set for network types 'mavclan', 'veth', 'phys'.
    
                  • LXC_NET_PEER: the name of the peer device on the host.
                    This is only set for 'veth' network types. Note that this
                    information is only available when **lxc.hook.version** is
                    set to 1.
    
           Whether this information is provided in the form of environment
           variables or as arguments to the script depends on the value of
           **lxc.hook.version**. If set to 1 then information is provided in the
           form of environment variables. If set to 0 information is provided
           as arguments to the script.
    
           Standard output from the script is logged at debug level.
           Standard error is not logged, but can be captured by the hook
           redirecting its standard error to standard output.
    
       **NEW PSEUDO TTY INSTANCE (DEVPTS)**
           For stricter isolation the container can have its own private
           instance of the pseudo tty.
    
           **lxc.pty.max**
                  If set, the container will have a new pseudo tty instance,
                  making this private to it. The value specifies the maximum
                  number of pseudo ttys allowed for a pty instance (this
                  limitation is not implemented yet).
    
       **CONTAINER SYSTEM CONSOLE**
           If the container is configured with a root filesystem and the
           inittab file is setup to use the console, you may want to specify
           where the output of this console goes.
    
           **lxc.console.buffer.size**
                  Setting this option instructs liblxc to allocate an in-
                  memory ringbuffer. The container's console output will be
                  written to the ringbuffer. Note that ringbuffer must be at
                  least as big as a standard page size. When passed a value
                  smaller than a single page size liblxc will allocate a
                  ringbuffer of a single page size. A page size is usually
                  4KB.  The keyword 'auto' will cause liblxc to allocate a
                  ringbuffer of 128KB.  When manually specifying a size for
                  the ringbuffer the value should be a power of 2 when
                  converted to bytes. Valid size prefixes are 'KB', 'MB',
                  'GB'. (Note that all conversions are based on multiples of
                  1024. That means 'KB' == 'KiB', 'MB' == 'MiB', 'GB' ==
                  'GiB'.  Additionally, the case of the suffix is ignored,
                  i.e. 'kB', 'KB' and 'Kb' are treated equally.)
    
           **lxc.console.size**
                  Setting this option instructs liblxc to place a limit on
                  the size of the console log file specified in
                  **lxc.console.logfile**. Note that size of the log file must be
                  at least as big as a standard page size. When passed a
                  value smaller than a single page size liblxc will set the
                  size of log file to a single page size. A page size is
                  usually 4KB.  The keyword 'auto' will cause liblxc to place
                  a limit of 128KB on the log file.  When manually specifying
                  a size for the log file the value should be a power of 2
                  when converted to bytes. Valid size prefixes are 'KB',
                  'MB', 'GB'. (Note that all conversions are based on
                  multiples of 1024. That means 'KB' == 'KiB', 'MB' == 'MiB',
                  'GB' == 'GiB'.  Additionally, the case of the suffix is
                  ignored, i.e. 'kB', 'KB' and 'Kb' are treated equally.)  If
                  users want to mirror the console ringbuffer on disk they
                  should set **lxc.console.size** equal to
                  **lxc.console.buffer.size**.
    
           **lxc.console.logfile**
                  Specify a path to a file where the console output will be
                  written.  Note that in contrast to the on-disk ringbuffer
                  logfile this file will keep growing potentially filling up
                  the users disks if not rotated and deleted. This problem
                  can also be avoided by using the in-memory ringbuffer
                  options **lxc.console.buffer.size** and
                  **lxc.console.buffer.logfile**.
    
           **lxc.console.rotate**
                  Whether to rotate the console logfile specified in
                  **lxc.console.logfile**. Users can send an API request to
                  rotate the logfile. Note that the old logfile will have the
                  same name as the original with the suffix ".1" appended.
                  Users wishing to prevent the console log file from filling
                  the disk should rotate the logfile and delete it if
                  unneeded. This problem can also be avoided by using the in-
                  memory ringbuffer options **lxc.console.buffer.size** and
                  **lxc.console.buffer.logfile**.
    
           **lxc.console.path**
                  Specify a path to a device to which the console will be
                  attached. The keyword 'none' will simply disable the
                  console. Note, when specifying 'none' and creating a device
                  node for the console in the container at /dev/console or
                  bind-mounting the hosts's /dev/console into the container
                  at /dev/console the container will have direct access to
                  the hosts's /dev/console.  This is dangerous when the
                  container has write access to the device and should thus be
                  used with caution.
    
       **CONSOLE THROUGH THE TTYS**
           This option is useful if the container is configured with a root
           filesystem and the inittab file is setup to launch a getty on the
           ttys. The option specifies the number of ttys to be available for
           the container. The number of gettys in the inittab file of the
           container should not be greater than the number of ttys specified
           in this option, otherwise the excess getty sessions will die and
           respawn indefinitely giving annoying messages on the console or in
           _/var/log/messages_.
    
           **lxc.tty.max**
                  Specify the number of tty to make available to the
                  container.
    
       **CONSOLE DEVICES LOCATION**
           LXC consoles are provided through Unix98 PTYs created on the host
           and bind-mounted over the expected devices in the container.  By
           default, they are bind-mounted over _/dev/console_ and _/dev/ttyN_.
           This can prevent package upgrades in the guest. Therefore you can
           specify a directory location (under _/dev_ under which LXC will
           create the files and bind-mount over them. These will then be
           symbolically linked to _/dev/console_ and _/dev/ttyN_.  A package
           upgrade can then succeed as it is able to remove and replace the
           symbolic links.
    
           **lxc.tty.dir**
                  Specify a directory under _/dev_ under which to create the
                  container console devices. Note that LXC will move any
                  bind-mounts or device nodes for /dev/console into this
                  directory.
    
       **/DEV DIRECTORY**
           By default, lxc creates a few symbolic links
           (fd,stdin,stdout,stderr) in the container's _/dev_ directory but
           does not automatically create device node entries. This allows the
           container's _/dev_ to be set up as needed in the container rootfs.
           If lxc.autodev is set to 1, then after mounting the container's
           rootfs LXC will mount a fresh tmpfs under _/dev_ (limited to 500K by
           default, unless defined in lxc.autodev.tmpfs.size) and fill in a
           minimal set of initial devices.  This is generally required when
           starting a container containing a "systemd" based "init" but may
           be optional at other times. Additional devices in the containers
           /dev directory may be created through the use of the
           **lxc.hook.autodev** hook.
    
           **lxc.autodev**
                  Set this to 0 to stop LXC from mounting and populating a
                  minimal _/dev_ when starting the container.
    
           **lxc.autodev.tmpfs.size**
                  Set this to define the size of the /dev tmpfs.  The default
                  value is 500000 (500K). If the parameter is used but
                  without value, the default value is used.
    
       **MOUNT POINTS**
           The mount points section specifies the different places to be
           mounted. These mount points will be private to the container and
           won't be visible by the processes running outside of the
           container. This is useful to mount /etc, /var or /home for
           examples.
    
           NOTE - LXC will generally ensure that mount targets and relative
           bind-mount sources are properly confined under the container root,
           to avoid attacks involving over-mounting host directories and
           files. (Symbolic links in absolute mount sources are ignored)
           However, if the container configuration first mounts a directory
           which is under the control of the container user, such as
           /home/joe, into the container at some _path_ , and then mounts under
           _path_ , then a TOCTTOU attack would be possible where the container
           user modifies a symbolic link under their home directory at just
           the right time.
    
           **lxc.mount.fstab**
                  specify a file location in the _fstab_ format, containing the
                  mount information. The mount target location can and in
                  most cases should be a relative path, which will become
                  relative to the mounted container root. For instance,
    
                               proc proc proc nodev,noexec,nosuid 0 0
    
                  Will mount a proc filesystem under the container's /proc,
                  regardless of where the root filesystem comes from. This is
                  resilient to block device backed filesystems as well as
                  container cloning.
    
                  Note that when mounting a filesystem from an image file or
                  block device the third field (fs_vfstype) cannot be auto as
                  with mount(8) but must be explicitly specified.
    
           **lxc.mount.entry**
                  Specify a mount point corresponding to a line in the fstab
                  format.  Moreover lxc supports mount propagation, such as
                  rshared or rprivate, and adds three additional mount
                  options.  **optional** don't fail if mount does not work.
                  **create=dir** or **create=file** to create dir (or file) when the
                  point will be mounted.  **relative** source path is taken to be
                  relative to the mounted container root. For instance,
    
                               dev/null proc/kcore none bind,relative 0 0
    
                  Will expand dev/null to ${**LXC_ROOTFS_MOUNT**}/dev/null, and
                  mount it to proc/kcore inside the container.
    
           **lxc.mount.auto**
                  specify which standard kernel file systems should be
                  automatically mounted. This may dramatically simplify the
                  configuration. The file systems are:
    
                  • **proc:mixed**(or **proc**): mount _/proc_ as read-write, but
                    remount _/proc/sys_ and _/proc/sysrq-trigger_ read-only for
                    security / container isolation purposes.
    
                  • **proc:rw** : mount _/proc_ as read-write
    
                  • **sys:mixed**(or **sys**): mount _/sys_ as read-only but with
                    /sys/devices/virtual/net writable.
    
                  • **sys:ro** : mount _/sys_ as read-only for security / container
                    isolation purposes.
    
                  • **sys:rw** : mount _/sys_ as read-write
    
                  • **cgroup:mixed** : Mount a tmpfs to _/sys/fs/cgroup_ , create
                    directories for all hierarchies to which the container is
                    added, create subdirectories in those hierarchies with
                    the name of the cgroup, and bind-mount the container's
                    own cgroup into that directory. The container will be
                    able to write to its own cgroup directory, but not the
                    parents, since they will be remounted read-only.
    
                  • **cgroup:mixed:force** : The **force** option will cause LXC to
                    perform the cgroup mounts for the container under all
                    circumstances.  Otherwise it is similar to **cgroup:mixed**.
                    This is mainly useful when the cgroup namespaces are
                    enabled where LXC will normally leave mounting cgroups to
                    the init binary of the container since it is perfectly
                    safe to do so.
    
                  • **cgroup:ro** : similar to **cgroup:mixed** , but everything will
                    be mounted read-only.
    
                  • **cgroup:ro:force** : The **force** option will cause LXC to
                    perform the cgroup mounts for the container under all
                    circumstances.  Otherwise it is similar to **cgroup:ro**.
                    This is mainly useful when the cgroup namespaces are
                    enabled where LXC will normally leave mounting cgroups to
                    the init binary of the container since it is perfectly
                    safe to do so.
    
                  • **cgroup:rw** : similar to **cgroup:mixed** , but everything will
                    be mounted read-write. Note that the paths leading up to
                    the container's own cgroup will be writable, but will not
                    be a cgroup filesystem but just part of the tmpfs of
                    _/sys/fs/cgroup_
    
                  • **cgroup:rw:force** : The **force** option will cause LXC to
                    perform the cgroup mounts for the container under all
                    circumstances.  Otherwise it is similar to **cgroup:rw**.
                    This is mainly useful when the cgroup namespaces are
                    enabled where LXC will normally leave mounting cgroups to
                    the init binary of the container since it is perfectly
                    safe to do so.
    
                  • **cgroup**(without specifier): defaults to **cgroup:rw** if the
                    container retains the CAP_SYS_ADMIN capability,
                    **cgroup:mixed** otherwise.
    
                  • **cgroup-full:mixed** : mount a tmpfs to _/sys/fs/cgroup_ ,
                    create directories for all hierarchies to which the
                    container is added, bind-mount the hierarchies from the
                    host to the container and make everything read-only
                    except the container's own cgroup. Note that compared to
                    **cgroup** , where all paths leading up to the container's own
                    cgroup are just simple directories in the underlying
                    tmpfs, here _/sys/fs/cgroup/$hierarchy_ will contain the
                    host's full cgroup hierarchy, albeit read-only outside
                    the container's own cgroup.  This may leak quite a bit of
                    information into the container.
    
                  • **cgroup-full:mixed:force** : The **force** option will cause LXC
                    to perform the cgroup mounts for the container under all
                    circumstances.  Otherwise it is similar to
                    **cgroup-full:mixed**.  This is mainly useful when the cgroup
                    namespaces are enabled where LXC will normally leave
                    mounting cgroups to the init binary of the container
                    since it is perfectly safe to do so.
    
                  • **cgroup-full:ro** : similar to **cgroup-full:mixed** , but
                    everything will be mounted read-only.
    
                  • **cgroup-full:ro:force** : The **force** option will cause LXC to
                    perform the cgroup mounts for the container under all
                    circumstances.  Otherwise it is similar to
                    **cgroup-full:ro**.  This is mainly useful when the cgroup
                    namespaces are enabled where LXC will normally leave
                    mounting cgroups to the init binary of the container
                    since it is perfectly safe to do so.
    
                  • **cgroup-full:rw** : similar to **cgroup-full:mixed** , but
                    everything will be mounted read-write. Note that in this
                    case, the container may escape its own cgroup. (Note also
                    that if the container has CAP_SYS_ADMIN support and can
                    mount the cgroup filesystem itself, it may do so anyway.)
    
                  • **cgroup-full:rw:force** : The **force** option will cause LXC to
                    perform the cgroup mounts for the container under all
                    circumstances.  Otherwise it is similar to
                    **cgroup-full:rw**.  This is mainly useful when the cgroup
                    namespaces are enabled where LXC will normally leave
                    mounting cgroups to the init binary of the container
                    since it is perfectly safe to do so.
    
                  • **cgroup-full**(without specifier): defaults to
                    **cgroup-full:rw** if the container retains the CAP_SYS_ADMIN
                    capability, **cgroup-full:mixed** otherwise.
    
           If cgroup namespaces are enabled, then any **cgroup** auto-mounting
           request will be ignored, since the container can mount the
           filesystems itself, and automounting can confuse the container
           init.
    
           Note that if automatic mounting of the cgroup filesystem is
           enabled, the tmpfs under _/sys/fs/cgroup_ will always be mounted
           read-write (but for the **:mixed** and **:ro** cases, the individual
           hierarchies, _/sys/fs/cgroup/$hierarchy_ , will be read-only). This
           is in order to work around a quirk in Ubuntu's **mountall**(8) command
           that will cause containers to wait for user input at boot if
           _/sys/fs/cgroup_ is mounted read-only and the container can't
           remount it read-write due to a lack of CAP_SYS_ADMIN.
    
           Examples:
    
                         lxc.mount.auto = proc sys cgroup
                         lxc.mount.auto = proc:rw sys:rw cgroup-full:rw
    
       **ROOT FILE SYSTEM**
           The root file system of the container can be different than that
           of the host system.
    
           **lxc.rootfs.path**
                  specify the root file system for the container. It can be
                  an image file, a directory or a block device. If not
                  specified, the container shares its root file system with
                  the host.
    
                  For directory or simple block-device backed containers, a
                  pathname can be used. If the rootfs is backed by a nbd
                  device, then _nbd:file:1_ specifies that _file_ should be
                  attached to a nbd device, and partition 1 should be mounted
                  as the rootfs.  _nbd:file_ specifies that the nbd device
                  itself should be mounted. _overlayfs:/lower:/upper_ specifies
                  that the rootfs should be an overlay with _/upper_ being
                  mounted read-write over a read-only mount of _/lower_.  For
                  _overlay_ multiple _/lower_ directories can be specified.
                  _loop:/file_ tells lxc to attach _/file_ to a loop device and
                  mount the loop device.
    
           **lxc.rootfs.mount**
                  where to recursively bind **lxc.rootfs.path** before pivoting.
                  This is to ensure success of the pivot_root(8) syscall. Any
                  directory suffices, the default should generally work.
    
           **lxc.rootfs.options**
                  Specify extra mount options to use when mounting the
                  rootfs.  The format of the mount options corresponds to the
                  format used in fstab. In addition, LXC supports the custom
                  **idmap=** mount option. This option can be used to tell LXC to
                  create an idmapped mount for the container's rootfs. This
                  is useful when the user doesn't want to recursively chown
                  the rootfs of the container to match the idmapping of the
                  user namespace the container is going to use. Instead an
                  idmapped mount can be used to handle this.  The argument
                  for **idmap=** can either be a path pointing to a user
                  namespace file that LXC will open and use to idmap the
                  rootfs or the special value "container" which will instruct
                  LXC to use the container's user namespace to idmap the
                  rootfs.
    
           **lxc.rootfs.managed**
                  Set this to 0 to indicate that LXC is not managing the
                  container storage, then LXC will not modify the container
                  storage. The default is 1.
    
       **CONTROL GROUPS ("CGROUPS")**
           The control group section contains the configuration for the
           different subsystem. **lxc** does not check the correctness of the
           subsystem name. This has the disadvantage of not detecting
           configuration errors until the container is started, but has the
           advantage of permitting any future subsystem.
    
           The kernel implementation of cgroups has changed significantly
           over the years. With Linux 4.5 support for a new cgroup filesystem
           was added usually referred to as "cgroup2" or "unified hierarchy".
           Since then the old cgroup filesystem is usually referred to as
           "cgroup1" or the "legacy hierarchies". Please see the cgroups
           manual page for a detailed explanation of the differences between
           the two versions.
    
           LXC distinguishes settings for the legacy and the unified
           hierarchy by using different configuration key prefixes. To alter
           settings for controllers in a legacy hierarchy the key prefix
           **lxc.cgroup.** must be used and in order to alter the settings for a
           controller in the unified hierarchy the **lxc.cgroup2.** key must be
           used. Note that LXC will ignore **lxc.cgroup.** settings on systems
           that only use the unified hierarchy. Conversely, it will ignore
           **lxc.cgroup2.** options on systems that only use legacy hierarchies.
    
           At its core a cgroup hierarchy is a way to hierarchically organize
           processes. Usually a cgroup hierarchy will have one or more
           "controllers" enabled. A "controller" in a cgroup hierarchy is
           usually responsible for distributing a specific type of system
           resource along the hierarchy. Controllers include the "pids"
           controller, the "cpu" controller, the "memory" controller and
           others. Some controllers however do not fall into the category of
           distributing a system resource, instead they are often referred to
           as "utility" controllers.  One utility controller is the device
           controller. Instead of distributing a system resource it allows
           one to manage device access.
    
           In the legacy hierarchy the device controller was implemented like
           most other controllers as a set of files that could be written to.
           These files where named "devices.allow" and "devices.deny". The
           legacy device controller allowed the implementation of both
           "allowlists" and "denylists".
    
           An allowlist is a device program that by default blocks access to
           all devices. In order to access specific devices "allow rules" for
           particular devices or device classes must be specified. In
           contrast, a denylist is a device program that by default allows
           access to all devices. In order to restrict access to specific
           devices "deny rules" for particular devices or device classes must
           be specified.
    
           In the unified cgroup hierarchy the implementation of the device
           controller has completely changed. Instead of files to read from
           and write to a eBPF program of **BPF_PROG_TYPE_CGROUP_DEVICE** can be
           attached to a cgroup. Even though the kernel implementation has
           changed completely LXC tries to allow for the same semantics to be
           followed in the legacy device cgroup and the unified eBPF-based
           device controller. The following paragraphs explain the semantics
           for the unified eBPF-based device controller.
    
           As mentioned the format for specifying device rules for the
           unified eBPF-based device controller is the same as for the legacy
           cgroup device controller; only the configuration key prefix has
           changed.  Specifically, device rules for the legacy cgroup device
           controller are specified via **lxc.cgroup.devices.allow** and
           **lxc.cgroup.devices.deny** whereas for the cgroup2 eBPF-based device
           controller **lxc.cgroup2.devices.allow** and **lxc.cgroup2.devices.deny**
           must be used.
    
           • A denylist device rule
    
                          lxc.cgroup2.devices.deny = a
    
             will cause LXC to instruct the kernel to block access to all
             devices by default. To grant access to devices allow device
             rules must be added via the **lxc.cgroup2.devices.allow** key. This
             is referred to as a "allowlist" device program.
    
           • An allowlist device rule
    
                          lxc.cgroup2.devices.allow = a
    
             will cause LXC to instruct the kernel to allow access to all
             devices by default. To deny access to devices deny device rules
             must be added via **lxc.cgroup2.devices.deny** key.  This is
             referred to as a "denylist" device program.
    
           • Specifying any of the aforementioned two rules will cause all
             previous rules to be cleared, i.e. the device list will be
             reset.
    
           • When an allowlist program is requested, i.e. access to all
             devices is blocked by default, specific deny rules for
             individual devices or device classes are ignored.
    
           • When a denylist program is requested, i.e. access to all devices
             is allowed by default, specific allow rules for individual
             devices or device classes are ignored.
    
           For example the set of rules:
    
                     lxc.cgroup2.devices.deny = a
                     lxc.cgroup2.devices.allow = c *:* m
                     lxc.cgroup2.devices.allow = b *:* m
                     lxc.cgroup2.devices.allow = c 1:3 rwm
    
           implements an allowlist device program, i.e. the kernel will block
           access to all devices not specifically allowed in this list. This
           particular program states that all character and block devices may
           be created but only /dev/null might be read or written.
    
           If we instead switch to the following set of rules:
    
                     lxc.cgroup2.devices.allow = a
                     lxc.cgroup2.devices.deny = c *:* m
                     lxc.cgroup2.devices.deny = b *:* m
                     lxc.cgroup2.devices.deny = c 1:3 rwm
    
           then LXC would instruct the kernel to implement a denylist, i.e.
           the kernel will allow access to all devices not specifically
           denied in this list. This particular program states that no
           character devices or block devices might be created and that
           /dev/null is not allow allowed to be read, written, or created.
    
           Now consider the same program but followed by a "global rule"
           which determines the type of device program (allowlist or
           denylist) as explained above:
    
                     lxc.cgroup2.devices.allow = a
                     lxc.cgroup2.devices.deny = c *:* m
                     lxc.cgroup2.devices.deny = b *:* m
                     lxc.cgroup2.devices.deny = c 1:3 rwm
                     lxc.cgroup2.devices.allow = a
    
           The last line will cause LXC to reset the device list without
           changing the type of device program.
    
           If we specify:
    
                     lxc.cgroup2.devices.allow = a
                     lxc.cgroup2.devices.deny = c *:* m
                     lxc.cgroup2.devices.deny = b *:* m
                     lxc.cgroup2.devices.deny = c 1:3 rwm
                     lxc.cgroup2.devices.deny = a
    
           instead then the last line will cause LXC to reset the device list
           and switch from an allowlist program to a denylist program.
    
           **lxc.cgroup.[controller name].[controller file]**
                  Specify the control group value to be set on a legacy
                  cgroup hierarchy. The controller name is the literal name
                  of the control group. The permitted names and the syntax of
                  their values is not dictated by LXC, instead it depends on
                  the features of the Linux kernel running at the time the
                  container is started, eg.  **lxc.cgroup.cpuset.cpus**
    
           **lxc.cgroup2.[controller name].[controller file]**
                  Specify the control group value to be set on the unified
                  cgroup hierarchy. The controller name is the literal name
                  of the control group. The permitted names and the syntax of
                  their values is not dictated by LXC, instead it depends on
                  the features of the Linux kernel running at the time the
                  container is started, eg.  **lxc.cgroup2.memory.high**
    
           **lxc.cgroup.dir**
                  specify a directory or path in which the container's cgroup
                  will be created. For example, setting **lxc.cgroup.dir =**
                  **my-cgroup/first** for a container named "c1" will create the
                  container's cgroup as a sub-cgroup of "my-cgroup". For
                  example, if the user's current cgroup "my-user" is located
                  in the root cgroup of the cpuset controller in a cgroup v1
                  hierarchy this would create the cgroup
                  "/sys/fs/cgroup/cpuset/my-user/my-cgroup/first/c1" for the
                  container. Any missing cgroups will be created by LXC. This
                  presupposes that the user has write access to its current
                  cgroup.
    
           **lxc.cgroup.dir.container**
                  This is similar to **lxc.cgroup.dir** , but must be used
                  together with **lxc.cgroup.dir.monitor** and affects only the
                  container's cgroup path. This option is mutually exclusive
                  with **lxc.cgroup.dir**.  Note that the final path the
                  container attaches to may be extended further by the
                  **lxc.cgroup.dir.container.inner** option.
    
           **lxc.cgroup.dir.monitor**
                  This is the monitor process counterpart to
                  **lxc.cgroup.dir.container**.
    
           **lxc.cgroup.dir.monitor.pivot**
                  On container termination the PID of the monitor process is
                  attached to this cgroup.  This path should not be a subpath
                  of any other configured cgroup dir to ensure proper removal
                  of other cgroup paths on container termination.
    
           **lxc.cgroup.dir.container.inner**
                  Specify an additional subdirectory where the cgroup
                  namespace will be created. With this option, the cgroup
                  limits will be applied to the outer path specified in
                  **lxc.cgroup.dir.container** , which is not accessible from
                  within the container, making it possible to better enforce
                  limits for privileged containers in a way they cannot
                  override them.  This only works in conjunction with the
                  **lxc.cgroup.dir.container** and **lxc.cgroup.dir.monitor** options
                  and has otherwise no effect.
    
           **lxc.cgroup.relative**
                  Set this to 1 to instruct LXC to never escape to the root
                  cgroup. This makes it easy for users to adhere to
                  restrictions enforced by cgroup2 and systemd. Specifically,
                  this makes it possible to run LXC containers as systemd
                  services.
    
       **CAPABILITIES**
           The capabilities can be dropped in the container if this one is
           run as root.
    
           **lxc.cap.drop**
                  Specify the capability to be dropped in the container. A
                  single line defining several capabilities with a space
                  separation is allowed. The format is the lower case of the
                  capability definition without the "CAP_" prefix, eg.
                  CAP_SYS_MODULE should be specified as sys_module. See
                  capabilities(7).  If used with no value, lxc will clear any
                  drop capabilities specified up to this point.
    
           **lxc.cap.keep**
                  Specify the capability to be kept in the container. All
                  other capabilities will be dropped. When a special value of
                  "none" is encountered, lxc will clear any keep capabilities
                  specified up to this point. A value of "none" alone can be
                  used to drop all capabilities.
    
       **NAMESPACES**
           A namespace can be cloned (**lxc.namespace.clone**), kept
           (**lxc.namespace.keep**) or shared (**lxc.namespace.share.[namespace**
           **identifier]**).
    
           **lxc.namespace.clone**
                  Specify namespaces which the container is supposed to be
                  created with. The namespaces to create are specified as a
                  space separated list. Each namespace must correspond to one
                  of the standard namespace identifiers as seen in the
                  _/proc/PID/ns_ directory.  When **lxc.namespace.clone** is not
                  explicitly set all namespaces supported by the kernel and
                  the current configuration will be used.
    
                  To create a new mount, net and ipc namespace set
                  **lxc.namespace.clone=mount net ipc**.
    
           **lxc.namespace.keep**
                  Specify namespaces which the container is supposed to
                  inherit from the process that created it. The namespaces to
                  keep are specified as a space separated list. Each
                  namespace must correspond to one of the standard namespace
                  identifiers as seen in the _/proc/PID/ns_ directory.  The
                  **lxc.namespace.keep** is a denylist option, i.e. it is useful
                  when enforcing that containers must keep a specific set of
                  namespaces.
    
                  To keep the network, user and ipc namespace set
                  **lxc.namespace.keep=user net ipc**.
    
                  Note that sharing pid namespaces will likely not work with
                  most init systems.
    
                  Note that if the container requests a new user namespace
                  and the container wants to inherit the network namespace it
                  needs to inherit the user namespace as well.
    
           **lxc.namespace.share.[namespace identifier]**
                  Specify a namespace to inherit from another container or
                  process.  The **[namespace identifier]** suffix needs to be
                  replaced with one of the namespaces that appear in the
                  _/proc/PID/ns_ directory.
    
                  To inherit the namespace from another process set the
                  **lxc.namespace.share.[namespace identifier]** to the PID of
                  the process, e.g. **lxc.namespace.share.net=42**.
    
                  To inherit the namespace from another container set the
                  **lxc.namespace.share.[namespace identifier]** to the name of
                  the container, e.g. **lxc.namespace.share.pid=c3**.
    
                  To inherit the namespace from another container located in
                  a different path than the standard liblxc path set the
                  **lxc.namespace.share.[namespace identifier]** to the full path
                  to the container, e.g.  **lxc.namespace.share.user=/opt/c3**.
    
                  In order to inherit namespaces the caller needs to have
                  sufficient privilege over the process or container.
    
                  Note that sharing pid namespaces between system containers
                  will likely not work with most init systems.
    
                  Note that if two processes are in different user namespaces
                  and one process wants to inherit the other's network
                  namespace it usually needs to inherit the user namespace as
                  well.
    
                  Note that without careful additional configuration of an
                  LSM, sharing user+pid namespaces with a task may allow that
                  task to escalate privileges to that of the task calling
                  liblxc.
    
           **lxc.time.offset.boot**
                  Specify a positive or negative offset for the boottime
                  clock. The format accepts hours (h), minutes (m), seconds
                  (s), milliseconds (ms), microseconds (us), and nanoseconds
                  (ns).
    
           **lxc.time.offset.monotonic**
                  Specify a positive or negative offset for the monotonic
                  clock. The format accepts hours (h), minutes (m), seconds
                  (s), milliseconds (ms), microseconds (us), and nanoseconds
                  (ns).
    
       **RESOURCE LIMITS**
           The soft and hard resource limits for the container can be
           changed.  Unprivileged containers can only lower them. Resources
           which are not explicitly specified will be inherited.
    
           **lxc.prlimit.[limit name]**
                  Specify the resource limit to be set. A limit is specified
                  as two colon separated values which are either numeric or
                  the word 'unlimited'. A single value can be used as a
                  shortcut to set both soft and hard limit to the same value.
                  The permitted names the "RLIMIT_" resource names in
                  lowercase without the "RLIMIT_" prefix, eg. RLIMIT_NOFILE
                  should be specified as "nofile". See setrlimit(2).  If used
                  with no value, lxc will clear the resource limit specified
                  up to this point. A resource with no explicitly configured
                  limitation will be inherited from the process starting up
                  the container.
    
       **SYSCTL**
           Configure kernel parameters for the container.
    
           **lxc.sysctl.[kernel parameters name]**
                  Specify the kernel parameters to be set. The parameters
                  available are those listed under /proc/sys/.  Note that not
                  all sysctls are namespaced. Changing Non-namespaced sysctls
                  will cause the system-wide setting to be modified.
                  sysctl(8).  If used with no value, lxc will clear the
                  parameters specified up to this point.
    
       **APPARMOR PROFILE**
           If lxc was compiled and installed with apparmor support, and the
           host system has apparmor enabled, then the apparmor profile under
           which the container should be run can be specified in the
           container configuration. The default is **lxc-container-default-cgns**
           if the host kernel is cgroup namespace aware, or **lxc-container-**
           **default** otherwise.
    
           **lxc.apparmor.profile**
                  Specify the apparmor profile under which the container
                  should be run. To specify that the container should be
                  unconfined, use
    
                  lxc.apparmor.profile = unconfined
    
                  If the apparmor profile should remain unchanged (i.e. if
                  you are nesting containers and are already confined), then
                  use
    
                  lxc.apparmor.profile = unchanged
    
                  If you instruct LXC to generate the apparmor profile, then
                  use
    
                  lxc.apparmor.profile = generated
    
           **lxc.apparmor.allow_incomplete**
                  Apparmor profiles are pathname based. Therefore many file
                  restrictions require mount restrictions to be effective
                  against a determined attacker. However, these mount
                  restrictions are not yet implemented in the upstream
                  kernel. Without the mount restrictions, the apparmor
                  profiles still protect against accidental damager.
    
                  If this flag is 0 (default), then the container will not be
                  started if the kernel lacks the apparmor mount features, so
                  that a regression after a kernel upgrade will be detected.
                  To start the container under partial apparmor protection,
                  set this flag to 1.
    
           **lxc.apparmor.allow_nesting**
                  If set this to 1, causes the following changes. When
                  generated apparmor profiles are used, they will contain the
                  necessary changes to allow creating a nested container. In
                  addition to the usual mount points, _/dev/.lxc/proc_ and
                  _/dev/.lxc/sys_ will contain procfs and sysfs mount points
                  without the lxcfs overlays, which, if generated apparmor
                  profiles are being used, will not be read/writable
                  directly.
    
           **lxc.apparmor.raw**
                  A list of raw AppArmor profile lines to append to the
                  profile. Only valid when using generated profiles.
    
       **SELINUX CONTEXT**
           If lxc was compiled and installed with SELinux support, and the
           host system has SELinux enabled, then the SELinux context under
           which the container should be run can be specified in the
           container configuration. The default is **unconfined_t** , which means
           that lxc will not attempt to change contexts.  See
           /usr/share/lxc/selinux/lxc.te for an example policy and more
           information.
    
           **lxc.selinux.context**
                  Specify the SELinux context under which the container
                  should be run or **unconfined_t**. For example
    
                  lxc.selinux.context = system_u:system_r:lxc_t:s0:c22
    
           **lxc.selinux.context.keyring**
                  Specify the SELinux context under which the container's
                  keyring should be created. By default this the same as
                  lxc.selinux.context, or the context lxc is executed under
                  if lxc.selinux.context has not been set.
    
                  lxc.selinux.context.keyring = system_u:system_r:lxc_t:s0:c22
    
       **KERNEL KEYRING**
           The Linux Keyring facility is primarily a way for various kernel
           components to retain or cache security data, authentication keys,
           encryption keys, and other data in the kernel. By default lxc will
           create a new session keyring for the started application.
    
           **lxc.keyring.session**
                  Disable the creation of new session keyring by lxc. The
                  started application will then inherit the current session
                  keyring.  By default, or when passing the value 1, a new
                  keyring will be created.
    
                  lxc.keyring.session = 0
    
       **SECCOMP CONFIGURATION**
           A container can be started with a reduced set of available system
           calls by loading a seccomp profile at startup. The seccomp
           configuration file must begin with a version number on the first
           line, a policy type on the second line, followed by the
           configuration.
    
           Versions 1 and 2 are currently supported. In version 1, the policy
           is a simple allowlist. The second line therefore must read
           "allowlist", with the rest of the file containing one (numeric)
           syscall number per line. Each syscall number is allowlisted, while
           every unlisted number is denylisted for use in the container
    
           In version 2, the policy may be denylist or allowlist, supports
           per-rule and per-policy default actions, and supports per-
           architecture system call resolution from textual names.
    
           An example denylist policy, in which all system calls are allowed
           except for mknod, which will simply do nothing and return 0
           (success), looks like:
    
                 2
                 denylist
                 mknod errno 0
                 ioctl notify
    
           Specifying "errno" as action will cause LXC to register a seccomp
           filter that will cause a specific errno to be returned to the
           caller. The errno value can be specified after the "errno" action
           word.
    
           Specifying "notify" as action will cause LXC to register a seccomp
           listener and retrieve a listener file descriptor from the kernel.
           When a syscall is made that is registered as "notify" the kernel
           will generate a poll event and send a message over the file
           descriptor. The caller can read this message, inspect the syscalls
           including its arguments. Based on this information the caller is
           expected to send back a message informing the kernel which action
           to take. Until that message is sent the kernel will block the
           calling process. The format of the messages to read and sent is
           documented in seccomp itself.
    
           **lxc.seccomp.profile**
                  Specify a file containing the seccomp configuration to load
                  before the container starts.
    
           **lxc.seccomp.allow_nesting**
                  If this flag is set to 1, then seccomp filters will be
                  stacked regardless of whether a seccomp profile is already
                  loaded.  This allows nested containers to load their own
                  seccomp profile.  The default setting is 0.
    
           **lxc.seccomp.notify.proxy**
                  Specify a unix socket to which LXC will connect and forward
                  seccomp events to. The path must be in the form
                  unix:/path/to/socket or unix:@socket. The former specifies
                  a path-bound unix domain socket while the latter specifies
                  an abstract unix domain socket.
    
           **lxc.seccomp.notify.cookie**
                  An additional string sent along with proxied seccomp
                  notification requests.
    
       **PR_SET_NO_NEW_PRIVS**
           With PR_SET_NO_NEW_PRIVS active execve() promises not to grant
           privileges to do anything that could not have been done without
           the execve() call (for example, rendering the set-user-ID and set-
           group-ID mode bits, and file capabilities non-functional).  Once
           set, this bit cannot be unset. The setting of this bit is
           inherited by children created by fork() and clone(), and preserved
           across execve().  Note that PR_SET_NO_NEW_PRIVS is applied after
           the container has changed into its intended AppArmor profile or
           SElinux context.
    
           **lxc.no_new_privs**
                  Specify whether the PR_SET_NO_NEW_PRIVS flag should be set
                  for the container. Set to 1 to activate.
    
       **UID MAPPINGS**
           A container can be started in a private user namespace with user
           and group id mappings. For instance, you can map userid 0 in the
           container to userid 200000 on the host. The root user in the
           container will be privileged in the container, but unprivileged on
           the host. Normally a system container will want a range of ids, so
           you would map, for instance, user and group ids 0 through 20,000
           in the container to the ids 200,000 through 220,000.
    
           **lxc.idmap**
                  Four values must be provided. First a character, either
                  'u', or 'g', to specify whether user or group ids are being
                  mapped. Next is the first userid as seen in the user
                  namespace of the container. Next is the userid as seen on
                  the host. Finally, a range indicating the number of
                  consecutive ids to map.
    
       **CONTAINER HOOKS**
           Container hooks are programs or scripts which can be executed at
           various times in a container's lifetime.
    
           When a container hook is executed, additional information is
           passed along. The **lxc.hook.version** argument can be used to
           determine if the following arguments are passed as command line
           arguments or through environment variables. The arguments are:
    
           • Container name.
    
           • Section (always 'lxc').
    
           • The hook type (i.e. 'clone' or 'pre-mount').
    
           • Additional arguments. In the case of the clone hook, any extra
             arguments passed will appear as further arguments to the hook.
             In the case of the stop hook, paths to filedescriptors for each
             of the container's namespaces along with their types are passed.
    
           The following environment variables are set:
    
           • LXC_CGNS_AWARE: indicator whether the container is cgroup
             namespace aware.
    
           • LXC_CONFIG_FILE: the path to the container configuration file.
    
           • LXC_HOOK_TYPE: the hook type (e.g. 'clone', 'mount', 'pre-
             mount'). Note that the existence of this environment variable is
             conditional on the value of **lxc.hook.version**. If it is set to 1
             then LXC_HOOK_TYPE will be set.
    
           • LXC_HOOK_SECTION: the section type (e.g. 'lxc', 'net'). Note
             that the existence of this environment variable is conditional
             on the value of **lxc.hook.version**. If it is set to 1 then
             LXC_HOOK_SECTION will be set.
    
           • LXC_HOOK_VERSION: the version of the hooks. This value is
             identical to the value of the container's **lxc.hook.version**
             config item. If it is set to 0 then old-style hooks are used. If
             it is set to 1 then new-style hooks are used.
    
           • LXC_LOG_LEVEL: the container's log level.
    
           • LXC_NAME: is the container's name.
    
           • LXC_[NAMESPACE IDENTIFIER]_NS: path under /proc/PID/fd/ to a
             file descriptor referring to the container's namespace. For each
             preserved namespace type there will be a separate environment
             variable. These environment variables will only be set if
             **lxc.hook.version** is set to 1.
    
           • LXC_ROOTFS_MOUNT: the path to the mounted root filesystem.
    
           • LXC_ROOTFS_PATH: this is the lxc.rootfs.path entry for the
             container. Note this is likely not where the mounted rootfs is
             to be found, use LXC_ROOTFS_MOUNT for that.
    
           • LXC_SRC_NAME: in the case of the clone hook, this is the
             original container's name.
    
           Standard output from the hooks is logged at debug level.  Standard
           error is not logged, but can be captured by the hook redirecting
           its standard error to standard output.
    
           **lxc.hook.version**
                  To pass the arguments in new style via environment
                  variables set to 1 otherwise set to 0 to pass them as
                  arguments.  This setting affects all hooks arguments that
                  were traditionally passed as arguments to the script.
                  Specifically, it affects the container name, section (e.g.
                  'lxc', 'net') and hook type (e.g.  'clone', 'mount', 'pre-
                  mount') arguments. If new-style hooks are used then the
                  arguments will be available as environment variables.  The
                  container name will be set in LXC_NAME. (This is set
                  independently of the value used for this config item.) The
                  section will be set in LXC_HOOK_SECTION and the hook type
                  will be set in LXC_HOOK_TYPE.  It also affects how the
                  paths to file descriptors referring to the container's
                  namespaces are passed. If set to 1 then for each namespace
                  a separate environment variable LXC_[NAMESPACE
                  IDENTIFIER]_NS will be set. If set to 0 then the paths will
                  be passed as arguments to the stop hook.
    
           **lxc.hook.pre-start**
                  A hook to be run in the host's namespace before the
                  container ttys, consoles, or mounts are up.
    
           **lxc.hook.pre-mount**
                  A hook to be run in the container's fs namespace but before
                  the rootfs has been set up. This allows for manipulation of
                  the rootfs, i.e. to mount an encrypted filesystem. Mounts
                  done in this hook will not be reflected on the host (apart
                  from mounts propagation), so they will be automatically
                  cleaned up when the container shuts down.
    
           **lxc.hook.mount**
                  A hook to be run in the container's namespace after
                  mounting has been done, but before the pivot_root.
    
           **lxc.hook.autodev**
                  A hook to be run in the container's namespace after
                  mounting has been done and after any mount hooks have run,
                  but before the pivot_root, if **lxc.autodev** == 1.  The
                  purpose of this hook is to assist in populating the /dev
                  directory of the container when using the autodev option
                  for systemd based containers. The container's /dev
                  directory is relative to the ${**LXC_ROOTFS_MOUNT**}
                  environment variable available when the hook is run.
    
           **lxc.hook.start-host**
                  A hook to be run in the host's namespace after the
                  container has been setup, and immediately before starting
                  the container init.
    
           **lxc.hook.start**
                  A hook to be run in the container's namespace immediately
                  before executing the container's init. This requires the
                  program to be available in the container.
    
           **lxc.hook.stop**
                  A hook to be run in the host's namespace with references to
                  the container's namespaces after the container has been
                  shut down. For each namespace an extra argument is passed
                  to the hook containing the namespace's type and a filename
                  that can be used to obtain a file descriptor to the
                  corresponding namespace, separated by a colon. The type is
                  the name as it would appear in the _/proc/PID/ns_ directory.
                  For instance for the mount namespace the argument usually
                  looks like _mnt:/proc/PID/fd/12_.
    
           **lxc.hook.post-stop**
                  A hook to be run in the host's namespace after the
                  container has been shut down.
    
           **lxc.hook.clone**
                  A hook to be run when the container is cloned to a new one.
                  See **lxc-clone**(1) for more information.
    
           **lxc.hook.destroy**
                  A hook to be run when the container is destroyed.
    
       **CONTAINER HOOKS ENVIRONMENT VARIABLES**
           A number of environment variables are made available to the
           startup hooks to provide configuration information and assist in
           the functioning of the hooks. Not all variables are valid in all
           contexts. In particular, all paths are relative to the host system
           and, as such, not valid during the **lxc.hook.start** hook.
    
           **LXC_NAME**
                  The LXC name of the container. Useful for logging messages
                  in common log environments. [**-n**]
    
           **LXC_CONFIG_FILE**
                  Host relative path to the container configuration file.
                  This gives the container to reference the original, top
                  level, configuration file for the container in order to
                  locate any additional configuration information not
                  otherwise made available. [**-f**]
    
           **LXC_CONSOLE**
                  The path to the console output of the container if not
                  NULL.  [**-c**] [**lxc.console.path**]
    
           **LXC_CONSOLE_LOGPATH**
                  The path to the console log output of the container if not
                  NULL.  [**-L**]
    
           **LXC_ROOTFS_MOUNT**
                  The mount location to which the container is initially
                  bound.  This will be the host relative path to the
                  container rootfs for the container instance being started
                  and is where changes should be made for that instance.
                  [**lxc.rootfs.mount**]
    
           **LXC_ROOTFS_PATH**
                  The host relative path to the container root which has been
                  mounted to the rootfs.mount location.  [**lxc.rootfs.path**]
    
           **LXC_SRC_NAME**
                  Only for the clone hook. Is set to the original container
                  name.
    
           **LXC_TARGET**
                  Only for the stop hook. Is set to "stop" for a container
                  shutdown or "reboot" for a container reboot.
    
           **LXC_CGNS_AWARE**
                  If unset, then this version of lxc is not aware of cgroup
                  namespaces. If set, it will be set to 1, and lxc is aware
                  of cgroup namespaces. Note this does not guarantee that
                  cgroup namespaces are enabled in the kernel. This is used
                  by the lxcfs mount hook.
    
       **LOGGING**
           Logging can be configured on a per-container basis. By default,
           depending upon how the lxc package was compiled, container startup
           is logged only at the ERROR level, and logged to a file named
           after the container (with '.log' appended) either under the
           container path, or under /var/log/lxc.
    
           Both the default log level and the log file can be specified in
           the container configuration file, overriding the default behavior.
           Note that the configuration file entries can in turn be overridden
           by the command line options to **lxc-start**.
    
           **lxc.log.level**
                  The level at which to log. The log level is an integer in
                  the range of 0..8 inclusive, where a lower number means
                  more verbose debugging. In particular 0 = trace, 1 = debug,
                  2 = info, 3 = notice, 4 = warn, 5 = error, 6 = critical, 7
                  = alert, and 8 = fatal. If unspecified, the level defaults
                  to 5 (error), so that only errors and above are logged.
    
                  Note that when a script (such as either a hook script or a
                  network interface up or down script) is called, the
                  script's standard output is logged at level 1, debug.
    
           **lxc.log.file**
                  The file to which logging info should be written.
    
           **lxc.log.syslog**
                  Send logging info to syslog. It respects the log level
                  defined in **lxc.log.level**. The argument should be the syslog
                  facility to use, valid ones are: daemon, local0, local1,
                  local2, local3, local4, local5, local5, local6, local7.
    
       **AUTOSTART**
           The autostart options support marking which containers should be
           auto-started and in what order. These options may be used by LXC
           tools directly or by external tooling provided by the
           distributions.
    
           **lxc.start.auto**
                  Whether the container should be auto-started.  Valid values
                  are 0 (off) and 1 (on).
    
           **lxc.start.delay**
                  How long to wait (in seconds) after the container is
                  started before starting the next one.
    
           **lxc.start.order**
                  An integer used to sort the containers when auto-starting a
                  series of containers at once. A lower value means an
                  earlier start.
    
           **lxc.monitor.unshare**
                  If not zero the mount namespace will be unshared from the
                  host before initializing the container (before running any
                  pre-start hooks). This requires the CAP_SYS_ADMIN
                  capability at startup.  Default is 0.
    
           **lxc.monitor.signal.pdeath**
                  Set the signal to be sent to the container's init when the
                  lxc monitor exits. By default it is set to SIGKILL which
                  will cause all container processes to be killed when the
                  lxc monitor process dies.  To ensure that containers stay
                  alive even if lxc monitor dies set this to 0.
    
           **lxc.group**
                  A multi-value key (can be used multiple times) to put the
                  container in a container group. Those groups can then be
                  used (amongst other things) to start a series of related
                  containers.
    
       **AUTOSTART AND SYSTEM BOOT**
           Each container can be part of any number of groups or no group at
           all.  Two groups are special. One is the NULL group, i.e. the
           container does not belong to any group. The other group is the
           "onboot" group.
    
           When the system boots with the LXC service enabled, it will first
           attempt to boot any containers with lxc.start.auto == 1 that is a
           member of the "onboot" group. The startup will be in order of
           lxc.start.order.  If an lxc.start.delay has been specified, that
           delay will be honored before attempting to start the next
           container to give the current container time to begin
           initialization and reduce overloading the host system. After
           starting the members of the "onboot" group, the LXC system will
           proceed to boot containers with lxc.start.auto == 1 which are not
           members of any group (the NULL group) and proceed as with the
           onboot group.
    
       **CONTAINER ENVIRONMENT**
           If you want to pass environment variables into the container (that
           is, environment variables which will be available to init and all
           of its descendents), you can use **lxc.environment** parameters to do
           so. Be careful that you do not pass in anything sensitive; any
           process in the container which doesn't have its environment
           scrubbed will have these variables available to it, and
           environment variables are always available via **/proc/PID/environ**.
    
           This configuration parameter can be specified multiple times; once
           for each environment variable you wish to configure.
    
           **lxc.environment**
                  Specify an environment variable to pass into the container.
                  Example:
    
                                lxc.environment = APP_ENV=production
                                lxc.environment = SYSLOG_SERVER=192.0.2.42
    
                  It is possible to inherit host environment variables by
                  setting the name of the variable without a "=" sign. For
                  example:
    
                                lxc.environment = PATH
    


## EXAMPLES



           In addition to the few examples given below, you will find some
           other examples of configuration file in
           /usr/share/doc/lxc/examples
    
       **NETWORK**
           This configuration sets up a container to use a veth pair device
           with one side plugged to a bridge br0 (which has been configured
           before on the system by the administrator). The virtual network
           device visible in the container is renamed to eth0.
    
                   lxc.uts.name = myhostname
                   lxc.net.0.type = veth
                   lxc.net.0.flags = up
                   lxc.net.0.link = br0
                   lxc.net.0.name = eth0
                   lxc.net.0.hwaddr = 4a:49:43:49:79:bf
                   lxc.net.0.ipv4.address = 10.2.3.5/24 10.2.3.255
                   lxc.net.0.ipv6.address = 2003:db8:1:0:214:1234:fe0b:3597
    
       **UID/GID MAPPING**
           This configuration will map both user and group ids in the range
           0-9999 in the container to the ids 100000-109999 on the host.
    
                   lxc.idmap = u 0 100000 10000
                   lxc.idmap = g 0 100000 10000
    
       **CONTROL GROUP**
           This configuration will setup several control groups for the
           application, cpuset.cpus restricts usage of the defined cpu,
           cpus.share prioritize the control group, devices.allow makes
           usable the specified devices.
    
                   lxc.cgroup.cpuset.cpus = 0,1
                   lxc.cgroup.cpu.shares = 1234
                   lxc.cgroup.devices.deny = a
                   lxc.cgroup.devices.allow = c 1:3 rw
                   lxc.cgroup.devices.allow = b 8:0 rw
    
       **COMPLEX CONFIGURATION**
           This example show a complex configuration making a complex network
           stack, using the control groups, setting a new hostname, mounting
           some locations and a changing root file system.
    
                   lxc.uts.name = complex
                   lxc.net.0.type = veth
                   lxc.net.0.flags = up
                   lxc.net.0.link = br0
                   lxc.net.0.hwaddr = 4a:49:43:49:79:bf
                   lxc.net.0.ipv4.address = 10.2.3.5/24 10.2.3.255
                   lxc.net.0.ipv6.address = 2003:db8:1:0:214:1234:fe0b:3597
                   lxc.net.0.ipv6.address = 2003:db8:1:0:214:5432:feab:3588
                   lxc.net.1.type = macvlan
                   lxc.net.1.flags = up
                   lxc.net.1.link = eth0
                   lxc.net.1.hwaddr = 4a:49:43:49:79:bd
                   lxc.net.1.ipv4.address = 10.2.3.4/24
                   lxc.net.1.ipv4.address = 192.168.10.125/24
                   lxc.net.1.ipv6.address = 2003:db8:1:0:214:1234:fe0b:3596
                   lxc.net.2.type = phys
                   lxc.net.2.flags = up
                   lxc.net.2.link = random0
                   lxc.net.2.hwaddr = 4a:49:43:49:79:ff
                   lxc.net.2.ipv4.address = 10.2.3.6/24
                   lxc.net.2.ipv6.address = 2003:db8:1:0:214:1234:fe0b:3297
                   lxc.cgroup.cpuset.cpus = 0,1
                   lxc.cgroup.cpu.shares = 1234
                   lxc.cgroup.devices.deny = a
                   lxc.cgroup.devices.allow = c 1:3 rw
                   lxc.cgroup.devices.allow = b 8:0 rw
                   lxc.mount.fstab = /etc/fstab.complex
                   lxc.mount.entry = /lib /root/myrootfs/lib none ro,bind 0 0
                   lxc.rootfs.path = dir:/mnt/rootfs.complex
                   lxc.rootfs.options = idmap=container
                   lxc.cap.drop = sys_module mknod setuid net_raw
                   lxc.cap.drop = mac_override
    


* * *