systemd.nspawn

SYSTEMD.NSPAWN(5)                systemd.nspawn                SYSTEMD.NSPAWN(5)



NAME
       systemd.nspawn - Container settings

SYNOPSIS
       /etc/systemd/nspawn/machine.nspawn

       /run/systemd/nspawn/machine.nspawn

       /var/lib/machines/machine.nspawn

DESCRIPTION
       An nspawn container settings file (suffix .nspawn) contains runtime
       configuration for a local container, and is used used by systemd-
       nspawn(1). Files of this type are named after the containers they define
       settings for. They are optional, and only required for containers whose
       execution environment shall differ from the defaults. Files of this type
       mostly contain settings that may also be set on the systemd-nspawn
       command line, and make it easier to persistently attach specific settings
       to specific containers. The syntax of these files is inspired by .desktop
       files, similarly to other configuration files supported by the systemd
       project. See systemd.syntax(7) for an overview.

.NSPAWN FILE DISCOVERY
       Files are searched for by appending the .nspawn suffix to the machine
       name of the container, as specified with the --machine= switch of
       systemd-nspawn, or derived from the directory or image file name. This
       file is first searched for in /etc/systemd/nspawn/ and
       /run/systemd/nspawn/. If found there, the settings are read and all of
       them take full effect (but may still be overridden by corresponding
       command line arguments). Otherwise, the file will then be searched for
       next to the image file or in the immediate parent of the root directory
       of the container. If the file is found there, only a subset of the
       settings will take effect however. All settings that possibly elevate
       privileges or grant additional access to resources of the host (such as
       files or directories) are ignored. To which options this applies is
       documented below.

       Persistent settings files created and maintained by the administrator
       (and thus trusted) should be placed in /etc/systemd/nspawn/, while
       automatically downloaded (and thus potentially untrusted) settings files
       are placed in /var/lib/machines/ instead (next to the container images),
       where their security impact is limited. In order to add privileged
       settings to .nspawn files acquired from the image vendor, it is
       recommended to copy the settings files into /etc/systemd/nspawn/ and edit
       them there, so that the privileged options become available. The precise
       algorithm for how the files are searched and interpreted may be
       configured with systemd-nspawn's --settings= switch, see systemd-
       nspawn(1) for details.

[EXEC] SECTION OPTIONS
       Settings files may include an [Exec] section, which carries various
       execution parameters:

       Boot=
           Takes a boolean argument, which defaults to off. If enabled,
           systemd-nspawn will automatically search for an init executable and
           invoke it. In this case, the specified parameters using Parameters=
           are passed as additional arguments to the init process. This setting
           corresponds to the --boot switch on the systemd-nspawn command line.
           This option may not be combined with ProcessTwo=yes. This option is
           specified by default in the systemd-nspawn@.service template unit.

       Ephemeral=
           Takes a boolean argument, which defaults to off, If enabled, the
           container is run with a temporary snapshot of its file system that is
           removed immediately when the container terminates. This is equivalent
           to the --ephemeral command line switch. See systemd-nspawn(1) for
           details about the specific options supported.

       ProcessTwo=
           Takes a boolean argument, which defaults to off. If enabled, the
           specified program is run as PID 2. A stub init process is run as PID
           1. This setting corresponds to the --as-pid2 switch on the
           systemd-nspawn command line. This option may not be combined with
           Boot=yes.

       Parameters=
           Takes a whitespace-separated list of arguments. Single ("'") and
           double (""") quotes may be used around arguments with whitespace.
           This is either a command line, beginning with the binary name to
           execute, or – if Boot= is enabled – the list of arguments to pass to
           the init process. This setting corresponds to the command line
           parameters passed on the systemd-nspawn command line.

           Note: Boot=no, Parameters=a b "c c" is the same as systemd-nspawn a b
           "c c", and Boot=yes, Parameters=b 'c c' is the same as systemd-nspawn
           --boot b 'c c'.

       Environment=
           Takes an environment variable assignment consisting of key and value,
           separated by "=". Sets an environment variable for the main process
           invoked in the container. This setting may be used multiple times to
           set multiple environment variables. It corresponds to the --setenv=
           command line switch.

       User=
           Takes a UNIX user name. Specifies the user name to invoke the main
           process of the container as. This user must be known in the
           container's user database. This corresponds to the --user= command
           line switch.

       WorkingDirectory=
           Selects the working directory for the process invoked in the
           container. Expects an absolute path in the container's file system
           namespace. This corresponds to the --chdir= command line switch.

       PivotRoot=
           Selects a directory to pivot to / inside the container when starting
           up. Takes a single path, or a pair of two paths separated by a colon.
           Both paths must be absolute, and are resolved in the container's file
           system namespace. This corresponds to the --pivot-root= command line
           switch.

       Capability=, DropCapability=
           Takes a space-separated list of Linux process capabilities (see
           capabilities(7) for details). The Capability= setting specifies
           additional capabilities to pass on top of the default set of
           capabilities. The DropCapability= setting specifies capabilities to
           drop from the default set. These settings correspond to the
           --capability= and --drop-capability= command line switches. Note that
           Capability= is a privileged setting, and only takes effect in .nspawn
           files in /etc/systemd/nspawn/ and /run/system/nspawn/ (see above). On
           the other hand, DropCapability= takes effect in all cases. If the
           special value "all" is passed, all capabilities are retained (or
           dropped).

       NoNewPrivileges=
           Takes a boolean argument that controls the PR_SET_NO_NEW_PRIVS flag
           for the container payload. This is equivalent to the
           --no-new-privileges= command line switch. See systemd-nspawn(1) for
           details.

       KillSignal=
           Specify the process signal to send to the container's PID 1 when
           nspawn itself receives SIGTERM, in order to trigger an orderly
           shutdown of the container. Defaults to SIGRTMIN+3 if Boot= is used
           (on systemd-compatible init systems SIGRTMIN+3 triggers an orderly
           shutdown). For a list of valid signals, see signal(7).

       Personality=
           Configures the kernel personality for the container. This is
           equivalent to the --personality= switch.

       MachineID=
           Configures the 128-bit machine ID (UUID) to pass to the container.
           This is equivalent to the --uuid= command line switch. This option is
           privileged (see above).

       PrivateUsers=
           Configures support for usernamespacing. This is equivalent to the
           --private-users= command line switch, and takes the same options.
           This option is privileged (see above). This option is the default if
           the systemd-nspawn@.service template unit file is used.

       NotifyReady=
           Configures support for notifications from the container's init
           process. This is equivalent to the --notify-ready= command line
           switch, and takes the same parameters. See systemd-nspawn(1) for
           details about the specific options supported.

       SystemCallFilter=
           Configures the system call filter applied to containers. This is
           equivalent to the --system-call-filter= command line switch, and
           takes the same list parameter. See systemd-nspawn(1) for details.

       LimitCPU=, LimitFSIZE=, LimitDATA=, LimitSTACK=, LimitCORE=, LimitRSS=,
       LimitNOFILE=, LimitAS=, LimitNPROC=, LimitMEMLOCK=, LimitLOCKS=,
       LimitSIGPENDING=, LimitMSGQUEUE=, LimitNICE=, LimitRTPRIO=, LimitRTTIME=
           Configures various types of resource limits applied to containers.
           This is equivalent to the --rlimit= command line switch, and takes
           the same arguments. See systemd-nspawn(1) for details.

       OOMScoreAdjust=
           Configures the OOM score adjustment value. This is equivalent to the
           --oom-score-adjust= command line switch, and takes the same argument.
           See systemd-nspawn(1) for details.

       CPUAffinity=
           Configures the CPU affinity. This is equivalent to the
           --cpu-affinity= command line switch, and takes the same argument. See
           systemd-nspawn(1) for details.

       Hostname=
           Configures the kernel hostname set for the container. This is
           equivalent to the --hostname= command line switch, and takes the same
           argument. See systemd-nspawn(1) for details.

       ResolvConf=
           Configures how /etc/resolv.conf in the container shall be handled.
           This is equivalent to the --resolv-conf= command line switch, and
           takes the same argument. See systemd-nspawn(1) for details.

       Timezone=
           Configures how /etc/localtime in the container shall be handled. This
           is equivalent to the --timezone= command line switch, and takes the
           same argument. See systemd-nspawn(1) for details.

       LinkJournal=
           Configures how to link host and container journal setups. This is
           equivalent to the --link-journal= command line switch, and takes the
           same parameter. See systemd-nspawn(1) for details.

[FILES] SECTION OPTIONS
       Settings files may include a [Files] section, which carries various
       parameters configuring the file system of the container:

       ReadOnly=
           Takes a boolean argument, which defaults to off. If specified, the
           container will be run with a read-only file system. This setting
           corresponds to the --read-only command line switch.

       Volatile=
           Takes a boolean argument, or the special value "state". This
           configures whether to run the container with volatile state and/or
           configuration. This option is equivalent to --volatile=, see systemd-
           nspawn(1) for details about the specific options supported.

       Bind=, BindReadOnly=
           Adds a bind mount from the host into the container. Takes a single
           path, a pair of two paths separated by a colon, or a triplet of two
           paths plus an option string separated by colons. This option may be
           used multiple times to configure multiple bind mounts. This option is
           equivalent to the command line switches --bind= and --bind-ro=, see
           systemd-nspawn(1) for details about the specific options supported.
           This setting is privileged (see above).

       TemporaryFileSystem=
           Adds a "tmpfs" mount to the container. Takes a path or a pair of path
           and option string, separated by a colon. This option may be used
           multiple times to configure multiple "tmpfs" mounts. This option is
           equivalent to the command line switch --tmpfs=, see systemd-nspawn(1)
           for details about the specific options supported. This setting is
           privileged (see above).

       Inaccessible=
           Masks the specified file or directory in the container, by
           over-mounting it with an empty file node of the same type with the
           most restrictive access mode. Takes a file system path as argument.
           This option may be used multiple times to mask multiple files or
           directories. This option is equivalent to the command line switch
           --inaccessible=, see systemd-nspawn(1) for details about the specific
           options supported. This setting is privileged (see above).

       Overlay=, OverlayReadOnly=
           Adds an overlay mount point. Takes a colon-separated list of paths.
           This option may be used multiple times to configure multiple overlay
           mounts. This option is equivalent to the command line switches
           --overlay= and --overlay-ro=, see systemd-nspawn(1) for details about
           the specific options supported. This setting is privileged (see
           above).

       PrivateUsersChown=
           Configures whether the ownership of the files and directories in the
           container tree shall be adjusted to the UID/GID range used, if
           necessary and user namespacing is enabled. This is equivalent to the
           --private-users-chown command line switch. This option is privileged
           (see above).

[NETWORK] SECTION OPTIONS
       Settings files may include a [Network] section, which carries various
       parameters configuring the network connectivity of the container:

       Private=
           Takes a boolean argument, which defaults to off. If enabled, the
           container will run in its own network namespace and not share network
           interfaces and configuration with the host. This setting corresponds
           to the --private-network command line switch.

       VirtualEthernet=
           Takes a boolean argument. Configures whether to create a virtual
           Ethernet connection ("veth") between host and the container. This
           setting implies Private=yes. This setting corresponds to the
           --network-veth command line switch. This option is privileged (see
           above). This option is the default if the systemd-nspawn@.service
           template unit file is used.

       VirtualEthernetExtra=
           Takes a colon-separated pair of interface names. Configures an
           additional virtual Ethernet connection ("veth") between host and the
           container. The first specified name is the interface name on the
           host, the second the interface name in the container. The latter may
           be omitted in which case it is set to the same name as the host side
           interface. This setting implies Private=yes. This setting corresponds
           to the --network-veth-extra= command line switch, and maybe be used
           multiple times. It is independent of VirtualEthernet=. Note that this
           option is unrelated to the Bridge= setting below, and thus any
           connections created this way are not automatically added to any
           bridge device on the host side. This option is privileged (see
           above).

       Interface=
           Takes a space-separated list of interfaces to add to the container.
           This option corresponds to the --network-interface= command line
           switch and implies Private=yes. This option is privileged (see
           above).

       MACVLAN=, IPVLAN=
           Takes a space-separated list of interfaces to add MACLVAN or IPVLAN
           interfaces to, which are then added to the container. These options
           correspond to the --network-macvlan= and --network-ipvlan= command
           line switches and imply Private=yes. These options are privileged
           (see above).

       Bridge=
           Takes an interface name. This setting implies VirtualEthernet=yes and
           Private=yes and has the effect that the host side of the created
           virtual Ethernet link is connected to the specified bridge interface.
           This option corresponds to the --network-bridge= command line switch.
           This option is privileged (see above).

       Zone=
           Takes a network zone name. This setting implies VirtualEthernet=yes
           and Private=yes and has the effect that the host side of the created
           virtual Ethernet link is connected to an automatically managed bridge
           interface named after the passed argument, prefixed with "vz-". This
           option corresponds to the --network-zone= command line switch. This
           option is privileged (see above).

       Port=
           Exposes a TCP or UDP port of the container on the host. This option
           corresponds to the --port= command line switch, see systemd-nspawn(1)
           for the precise syntax of the argument this option takes. This option
           is privileged (see above).

SEE ALSO
       systemd(1), systemd-nspawn(1), systemd.directives(7)



systemd 247                                                    SYSTEMD.NSPAWN(5)