systemd-nspawn(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ENVIRONMENT | EXAMPLES | EXIT STATUS | SEE ALSO | NOTES | COLOPHON

SYSTEMD-NSPAWN(1)              systemd-nspawn              SYSTEMD-NSPAWN(1)

NAME         top

       systemd-nspawn - Spawn a command or OS in a light-weight container

SYNOPSIS         top

       systemd-nspawn [OPTIONS...] [COMMAND [ARGS...]]

       systemd-nspawn --boot [OPTIONS...] [ARGS...]

DESCRIPTION         top

       systemd-nspawn may be used to run a command or OS in a light-weight
       namespace container. In many ways it is similar to chroot(1), but
       more powerful since it fully virtualizes the file system hierarchy,
       as well as the process tree, the various IPC subsystems and the host
       and domain name.

       systemd-nspawn may be invoked on any directory tree containing an
       operating system tree, using the --directory= command line option. By
       using the --machine= option an OS tree is automatically searched for
       in a couple of locations, most importantly in /var/lib/machines, the
       suggested directory to place OS container images installed on the
       system.

       In contrast to chroot(1) systemd-nspawn may be used to boot full
       Linux-based operating systems in a container.

       systemd-nspawn limits access to various kernel interfaces in the
       container to read-only, such as /sys, /proc/sys or /sys/fs/selinux.
       The host's network interfaces and the system clock may not be changed
       from within the container. Device nodes may not be created. The host
       system cannot be rebooted and kernel modules may not be loaded from
       within the container.

       Use a tool like dnf(8), debootstrap(8), or pacman(8) to set up an OS
       directory tree suitable as file system hierarchy for systemd-nspawn
       containers. See the Examples section below for details on suitable
       invocation of these commands.

       As a safety check systemd-nspawn will verify the existence of
       /usr/lib/os-release or /etc/os-release in the container tree before
       starting the container (see os-release(5)). It might be necessary to
       add this file to the container tree manually if the OS of the
       container is too old to contain this file out-of-the-box.

       systemd-nspawn may be invoked directly from the interactive command
       line or run as system service in the background. In this mode each
       container instance runs as its own service instance; a default
       template unit file systemd-nspawn@.service is provided to make this
       easy, taking the container name as instance identifier. Note that
       different default options apply when systemd-nspawn is invoked by the
       template unit file than interactively on the command line. Most
       importantly the template unit file makes use of the --boot which is
       not the default in case systemd-nspawn is invoked from the
       interactive command line. Further differences with the defaults are
       documented along with the various supported options below.

       The machinectl(1) tool may be used to execute a number of operations
       on containers. In particular it provides easy-to-use commands to run
       containers as system services using the systemd-nspawn@.service
       template unit file.

       Along with each container a settings file with the .nspawn suffix may
       exist, containing additional settings to apply when running the
       container. See systemd.nspawn(5) for details. Settings files override
       the default options used by the systemd-nspawn@.service template unit
       file, making it usually unnecessary to alter this template file
       directly.

       Note that systemd-nspawn will mount file systems private to the
       container to /dev, /run and similar. These will not be visible
       outside of the container, and their contents will be lost when the
       container exits.

       Note that running two systemd-nspawn containers from the same
       directory tree will not make processes in them see each other. The
       PID namespace separation of the two containers is complete and the
       containers will share very few runtime objects except for the
       underlying file system. Use machinectl(1)'s login or shell commands
       to request an additional login session in a running container.

       systemd-nspawn implements the Container Interface[1] specification.

       While running, containers invoked with systemd-nspawn are registered
       with the systemd-machined(8) service that keeps track of running
       containers, and provides programming interfaces to interact with
       them.

OPTIONS         top

       If option -b is specified, the arguments are used as arguments for
       the init program. Otherwise, COMMAND specifies the program to launch
       in the container, and the remaining arguments are used as arguments
       for this program. If --boot is not used and no arguments are
       specified, a shell is launched in the container.

       The following options are understood:

       -q, --quiet
           Turns off any status output by the tool itself. When this switch
           is used, the only output from nspawn will be the console output
           of the container OS itself.

       --settings=MODE
           Controls whether systemd-nspawn shall search for and use
           additional per-container settings from .nspawn files. Takes a
           boolean or the special values override or trusted.

           If enabled (the default), a settings file named after the machine
           (as specified with the --machine= setting, or derived from the
           directory or image file name) with the suffix .nspawn is searched
           in /etc/systemd/nspawn/ and /run/systemd/nspawn/. If it is found
           there, its settings are read and used. If it is not found there,
           it is subsequently searched in the same directory as the image
           file or in the immediate parent of the root directory of the
           container. In this case, if the file is found, its settings will
           be also read and used, but potentially unsafe settings are
           ignored. Note that in both these cases, settings on the command
           line take precedence over the corresponding settings from loaded
           .nspawn files, if both are specified. Unsafe settings are
           considered all settings that elevate the container's privileges
           or grant access to additional resources such as files or
           directories of the host. For details about the format and
           contents of .nspawn files, consult systemd.nspawn(5).

           If this option is set to override, the file is searched, read and
           used the same way, however, the order of precedence is reversed:
           settings read from the .nspawn file will take precedence over the
           corresponding command line options, if both are specified.

           If this option is set to trusted, the file is searched, read and
           used the same way, but regardless of being found in
           /etc/systemd/nspawn/, /run/systemd/nspawn/ or next to the image
           file or container root directory, all settings will take effect,
           however, command line arguments still take precedence over
           corresponding settings.

           If disabled, no .nspawn file is read and no settings except the
           ones on the command line are in effect.

   Image Options
       -D, --directory=
           Directory to use as file system root for the container.

           If neither --directory=, nor --image= is specified the directory
           is determined by searching for a directory named the same as the
           machine name specified with --machine=. See machinectl(1) section
           "Files and Directories" for the precise search path.

           If neither --directory=, --image=, nor --machine= are specified,
           the current directory will be used. May not be specified together
           with --image=.

       --template=
           Directory or "btrfs" subvolume to use as template for the
           container's root directory. If this is specified and the
           container's root directory (as configured by --directory=) does
           not yet exist it is created as "btrfs" snapshot (if supported) or
           plain directory (otherwise) and populated from this template
           tree. Ideally, the specified template path refers to the root of
           a "btrfs" subvolume, in which case a simple copy-on-write
           snapshot is taken, and populating the root directory is instant.
           If the specified template path does not refer to the root of a
           "btrfs" subvolume (or not even to a "btrfs" file system at all),
           the tree is copied (though possibly in a 'reflink' copy-on-write
           scheme — if the file system supports that), which can be
           substantially more time-consuming. Note that the snapshot taken
           is of the specified directory or subvolume, including all
           subdirectories and subvolumes below it, but excluding any
           sub-mounts. May not be specified together with --image= or
           --ephemeral.

           Note that this switch leaves hostname, machine ID and all other
           settings that could identify the instance unmodified.

       -x, --ephemeral
           If specified, the container is run with a temporary snapshot of
           its file system that is removed immediately when the container
           terminates. May not be specified together with --template=.

           Note that this switch leaves hostname, machine ID and all other
           settings that could identify the instance unmodified. Please note
           that — as with --template= — taking the temporary snapshot is
           more efficient on file systems that support subvolume snapshots
           or 'reflinks' natively ("btrfs" or new "xfs") than on more
           traditional file systems that do not ("ext4"). Note that the
           snapshot taken is of the specified directory or subvolume,
           including all subdirectories and subvolumes below it, but
           excluding any sub-mounts.

           With this option no modifications of the container image are
           retained. Use --volatile= (described below) for other mechanisms
           to restrict persistency of container images during runtime.

       -i, --image=
           Disk image to mount the root directory for the container from.
           Takes a path to a regular file or to a block device node. The
           file or block device must contain either:

           ·   An MBR partition table with a single partition of type 0x83
               that is marked bootable.

           ·   A GUID partition table (GPT) with a single partition of type
               0fc63daf-8483-4772-8e79-3d69d8477de4.

           ·   A GUID partition table (GPT) with a marked root partition
               which is mounted as the root directory of the container.
               Optionally, GPT images may contain a home and/or a server
               data partition which are mounted to the appropriate places in
               the container. All these partitions must be identified by the
               partition types defined by the Discoverable Partitions
               Specification[2].

           ·   No partition table, and a single file system spanning the
               whole image.

           On GPT images, if an EFI System Partition (ESP) is discovered, it
           is automatically mounted to /efi (or /boot as fallback) in case a
           directory by this name exists and is empty.

           Partitions encrypted with LUKS are automatically decrypted. Also,
           on GPT images dm-verity data integrity hash partitions are set up
           if the root hash for them is specified using the --root-hash=
           option.

           Any other partitions, such as foreign partitions or swap
           partitions are not mounted. May not be specified together with
           --directory=, --template=.

       --oci-bundle=
           Takes the path to an OCI runtime bundle to invoke, as specified
           in the OCI Runtime Specification[3]. In this case no .nspawn file
           is loaded, and the root directory and various settings are read
           from the OCI runtime JSON data (but data passed on the command
           line takes precedence).

       --read-only
           Mount the container's root file system (and any other file
           systems container in the container image) read-only. This has no
           effect on additional mounts made with --bind=, --tmpfs= and
           similar options. This mode is implied if the container image file
           or directory is marked read-only itself. It is also implied if
           --volatile= is used. In this case the container image on disk is
           strictly read-only, while changes are permitted but kept
           non-persistently in memory only. For further details, see below.

       --volatile, --volatile=MODE
           Boots the container in volatile mode. When no mode parameter is
           passed or when mode is specified as yes, full volatile mode is
           enabled. This means the root directory is mounted as a mostly
           unpopulated "tmpfs" instance, and /usr/ from the OS tree is
           mounted into it in read-only mode (the system thus starts up with
           read-only OS image, but pristine state and configuration, any
           changes are lost on shutdown). When the mode parameter is
           specified as state, the OS tree is mounted read-only, but /var/
           is mounted as a writable "tmpfs" instance into it (the system
           thus starts up with read-only OS resources and configuration, but
           pristine state, and any changes to the latter are lost on
           shutdown). When the mode parameter is specified as overlay the
           read-only root file system is combined with a writable tmpfs
           instance through "overlayfs", so that it appears at it normally
           would, but any changes are applied to the temporary file system
           only and lost when the container is terminated. When the mode
           parameter is specified as no (the default), the whole OS tree is
           made available writable (unless --read-only is specified, see
           above).

           Note that if one of the volatile modes is chosen, its effect is
           limited to the root file system (or /var/ in case of state), and
           any other mounts placed in the hierarchy are unaffected —
           regardless if they are established automatically (e.g. the EFI
           system partition that might be mounted to /efi/ or /boot/) or
           explicitly (e.g. through an additional command line option such
           as --bind=, see below). This means, even if --volatile=overlay is
           used changes to /efi/ or /boot/ are prohibited in case such a
           partition exists in the container image operated on, and even if
           --volatile=state is used the hypothetical file /etc/foobar is
           potentially writable if --bind=/etc/foobar if used to mount it
           from outside the read-only container /etc directory.

           The --ephemeral option is closely related to this setting, and
           provides similar behaviour by making a temporary, ephemeral copy
           of the whole OS image and executing that. For further details,
           see above.

           The --tmpfs= and --overlay= options provide similar
           functionality, but for specific sub-directories of the OS image
           only. For details, see below.

           This option provides similar functionality for containers as the
           "systemd.volatile=" kernel command line switch provides for host
           systems. See kernel-command-line(7) for details.

           Note that setting this option to yes or state will only work
           correctly with operating systems in the container that can boot
           up with only /usr/ mounted, and are able to automatically
           populate /var/ (and /etc/ in case of "--volatile=yes").
           Specifically, this means that operating systems that follow the
           historic split of /bin/ and /lib/ (and related directories) from
           /usr/ (i.e. where the former are not symlinks into the latter)
           are not supported by "--volatile=yes" as container payload. The
           overlay option does not require any particular preparations in
           the OS, but do note that "overlayfs" behaviour differs from
           regular file systems in a number of ways, and hence compatibility
           is limited.

       --root-hash=
           Takes a data integrity (dm-verity) root hash specified in
           hexadecimal. This option enables data integrity checks using
           dm-verity, if the used image contains the appropriate integrity
           data (see above). The specified hash must match the root hash of
           integrity data, and is usually at least 256 bits (and hence 64
           formatted hexadecimal characters) long (in case of SHA256 for
           example). If this option is not specified, but the image file
           carries the "user.verity.roothash" extended file attribute (see
           xattr(7)), then the root hash is read from it, also as formatted
           hexadecimal characters. If the extended file attribute is not
           found (or is not supported by the underlying file system), but a
           file with the .roothash suffix is found next to the image file,
           bearing otherwise the same name, the root hash is read from it
           and automatically used, also as formatted hexadecimal characters.

       --pivot-root=
           Pivot the specified directory to / inside the container, and
           either unmount the container's old root, or pivot it to another
           specified directory. Takes one of: a path argument — in which
           case the specified path will be pivoted to / and the old root
           will be unmounted; or a colon-separated pair of new root path and
           pivot destination for the old root. The new root path will be
           pivoted to /, and the old / will be pivoted to the other
           directory. Both paths must be absolute, and are resolved in the
           container's file system namespace.

           This is for containers which have several bootable directories in
           them; for example, several OSTree[4] deployments. It emulates the
           behavior of the boot loader and initial RAM disk which normally
           select which directory to mount as the root and start the
           container's PID 1 in.

   Execution Options
       -a, --as-pid2
           Invoke the shell or specified program as process ID (PID) 2
           instead of PID 1 (init). By default, if neither this option nor
           --boot is used, the selected program is run as the process with
           PID 1, a mode only suitable for programs that are aware of the
           special semantics that the process with PID 1 has on UNIX. For
           example, it needs to reap all processes reparented to it, and
           should implement sysvinit compatible signal handling
           (specifically: it needs to reboot on SIGINT, reexecute on
           SIGTERM, reload configuration on SIGHUP, and so on). With
           --as-pid2 a minimal stub init process is run as PID 1 and the
           selected program is executed as PID 2 (and hence does not need to
           implement any special semantics). The stub init process will reap
           processes as necessary and react appropriately to signals. It is
           recommended to use this mode to invoke arbitrary commands in
           containers, unless they have been modified to run correctly as
           PID 1. Or in other words: this switch should be used for pretty
           much all commands, except when the command refers to an init or
           shell implementation, as these are generally capable of running
           correctly as PID 1. This option may not be combined with --boot.

       -b, --boot
           Automatically search for an init program and invoke it as PID 1,
           instead of a shell or a user supplied program. If this option is
           used, arguments specified on the command line are used as
           arguments for the init program. This option may not be combined
           with --as-pid2.

           The following table explains the different modes of invocation
           and relationship to --as-pid2 (see above):

           Table 1. Invocation Mode
           ┌──────────────────────┬───────────────────────────┐
           │Switch                Explanation               │
           ├──────────────────────┼───────────────────────────┤
           │Neither --as-pid2 nor │ The passed parameters are │
           │--boot specified      │ interpreted as the        │
           │                      │ command line, which is    │
           │                      │ executed as PID 1 in the  │
           │                      │ container.                │
           ├──────────────────────┼───────────────────────────┤
           │--as-pid2 specified   │ The passed parameters are │
           │                      │ interpreted as the        │
           │                      │ command line, which is    │
           │                      │ executed as PID 2 in the  │
           │                      │ container. A stub init    │
           │                      │ process is run as PID 1.  │
           ├──────────────────────┼───────────────────────────┤
           │--boot specified      │ An init program is        │
           │                      │ automatically searched    │
           │                      │ for and run as PID 1 in   │
           │                      │ the container. The passed │
           │                      │ parameters are used as    │
           │                      │ invocation parameters for │
           │                      │ this process.             │
           └──────────────────────┴───────────────────────────┘
           Note that --boot is the default mode of operation if the
           systemd-nspawn@.service template unit file is used.

       --chdir=
           Change to the specified working directory before invoking the
           process in the container. Expects an absolute path in the
           container's file system namespace.

       -E NAME=VALUE, --setenv=NAME=VALUE
           Specifies an environment variable assignment to pass to the init
           process in the container, in the format "NAME=VALUE". This may be
           used to override the default variables or to set additional
           variables. This parameter may be used more than once.

       -u, --user=
           After transitioning into the container, change to the specified
           user-defined in the container's user database. Like all other
           systemd-nspawn features, this is not a security feature and
           provides protection against accidental destructive operations
           only.

       --kill-signal=
           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). If --boot is not used and this option is not
           specified the container's processes are terminated abruptly via
           SIGKILL. For a list of valid signals, see signal(7).

       --notify-ready=
           Configures support for notifications from the container's init
           process.  --notify-ready= takes a boolean (no and yes). With
           option no systemd-nspawn notifies systemd with a "READY=1"
           message when the init process is created. With option yes
           systemd-nspawn waits for the "READY=1" message from the init
           process in the container before sending its own to systemd. For
           more details about notifications see sd_notify(3)).

   System Identity Options
       -M, --machine=
           Sets the machine name for this container. This name may be used
           to identify this container during its runtime (for example in
           tools like machinectl(1) and similar), and is used to initialize
           the container's hostname (which the container can choose to
           override, however). If not specified, the last component of the
           root directory path of the container is used, possibly suffixed
           with a random identifier in case --ephemeral mode is selected. If
           the root directory selected is the host's root directory the
           host's hostname is used as default instead.

       --hostname=
           Controls the hostname to set within the container, if different
           from the machine name. Expects a valid hostname as argument. If
           this option is used, the kernel hostname of the container will be
           set to this value, otherwise it will be initialized to the
           machine name as controlled by the --machine= option described
           above. The machine name is used for various aspect of
           identification of the container from the outside, the kernel
           hostname configurable with this option is useful for the
           container to identify itself from the inside. It is usually a
           good idea to keep both forms of identification synchronized, in
           order to avoid confusion. It is hence recommended to avoid usage
           of this option, and use --machine= exclusively. Note that
           regardless whether the container's hostname is initialized from
           the name set with --hostname= or the one set with --machine=, the
           container can later override its kernel hostname freely on its
           own as well.

       --uuid=
           Set the specified UUID for the container. The init system will
           initialize /etc/machine-id from this if this file is not set yet.
           Note that this option takes effect only if /etc/machine-id in the
           container is unpopulated.

   Property Options
       -S, --slice=
           Make the container part of the specified slice, instead of the
           default machine.slice. This applies only if the machine is run in
           its own scope unit, i.e. if --keep-unit isn't used.

       --property=
           Set a unit property on the scope unit to register for the
           machine. This applies only if the machine is run in its own scope
           unit, i.e. if --keep-unit isn't used. Takes unit property
           assignments in the same format as systemctl set-property. This is
           useful to set memory limits and similar for container.

       --register=
           Controls whether the container is registered with
           systemd-machined(8). Takes a boolean argument, which defaults to
           "yes". This option should be enabled when the container runs a
           full Operating System (more specifically: a system and service
           manager as PID 1), and is useful to ensure that the container is
           accessible via machinectl(1) and shown by tools such as ps(1). If
           the container does not run a service manager, it is recommended
           to set this option to "no".

       --keep-unit
           Instead of creating a transient scope unit to run the container
           in, simply use the service or scope unit systemd-nspawn has been
           invoked in. If --register=yes is set this unit is registered with
           systemd-machined(8). This switch should be used if systemd-nspawn
           is invoked from within a service unit, and the service unit's
           sole purpose is to run a single systemd-nspawn container. This
           option is not available if run from a user session.

           Note that passing --keep-unit disables the effect of --slice= and
           --property=. Use --keep-unit and --register=no in combination to
           disable any kind of unit allocation or registration with
           systemd-machined.

   User Namespacing Options
       --private-users=
           Controls user namespacing. If enabled, the container will run
           with its own private set of UNIX user and group ids (UIDs and
           GIDs). This involves mapping the private UIDs/GIDs used in the
           container (starting with the container's root user 0 and up) to a
           range of UIDs/GIDs on the host that are not used for other
           purposes (usually in the range beyond the host's UID/GID 65536).
           The parameter may be specified as follows:

            1. If one or two colon-separated numbers are specified, user
               namespacing is turned on. The first parameter specifies the
               first host UID/GID to assign to the container, the second
               parameter specifies the number of host UIDs/GIDs to assign to
               the container. If the second parameter is omitted, 65536
               UIDs/GIDs are assigned.

            2. If the parameter is omitted, or true, user namespacing is
               turned on. The UID/GID range to use is determined
               automatically from the file ownership of the root directory
               of the container's directory tree. To use this option, make
               sure to prepare the directory tree in advance, and ensure
               that all files and directories in it are owned by UIDs/GIDs
               in the range you'd like to use. Also, make sure that used
               file ACLs exclusively reference UIDs/GIDs in the appropriate
               range. If this mode is used the number of UIDs/GIDs assigned
               to the container for use is 65536, and the UID/GID of the
               root directory must be a multiple of 65536.

            3. If the parameter is false, user namespacing is turned off.
               This is the default.

            4. The special value "pick" turns on user namespacing. In this
               case the UID/GID range is automatically chosen. As first
               step, the file owner of the root directory of the container's
               directory tree is read, and it is checked that it is
               currently not used by the system otherwise (in particular,
               that no other container is using it). If this check is
               successful, the UID/GID range determined this way is used,
               similar to the behavior if "yes" is specified. If the check
               is not successful (and thus the UID/GID range indicated in
               the root directory's file owner is already used elsewhere) a
               new – currently unused – UID/GID range of 65536 UIDs/GIDs is
               randomly chosen between the host UID/GIDs of 524288 and
               1878982656, always starting at a multiple of 65536. This
               setting implies --private-users-chown (see below), which has
               the effect that the files and directories in the container's
               directory tree will be owned by the appropriate users of the
               range picked. Using this option makes user namespace behavior
               fully automatic. Note that the first invocation of a
               previously unused container image might result in picking a
               new UID/GID range for it, and thus in the (possibly
               expensive) file ownership adjustment operation. However,
               subsequent invocations of the container will be cheap (unless
               of course the picked UID/GID range is assigned to a different
               use by then).

           It is recommended to assign at least 65536 UIDs/GIDs to each
           container, so that the usable UID/GID range in the container
           covers 16 bit. For best security, do not assign overlapping
           UID/GID ranges to multiple containers. It is hence a good idea to
           use the upper 16 bit of the host 32-bit UIDs/GIDs as container
           identifier, while the lower 16 bit encode the container UID/GID
           used. This is in fact the behavior enforced by the
           --private-users=pick option.

           When user namespaces are used, the GID range assigned to each
           container is always chosen identical to the UID range.

           In most cases, using --private-users=pick is the recommended
           option as it enhances container security massively and operates
           fully automatically in most cases.

           Note that the picked UID/GID range is not written to /etc/passwd
           or /etc/group. In fact, the allocation of the range is not stored
           persistently anywhere, except in the file ownership of the files
           and directories of the container.

           Note that when user namespacing is used file ownership on disk
           reflects this, and all of the container's files and directories
           are owned by the container's effective user and group IDs. This
           means that copying files from and to the container image requires
           correction of the numeric UID/GID values, according to the
           UID/GID shift applied.

       --private-users-chown
           If specified, all files and directories in the container's
           directory tree will be adjusted so that they are owned by the
           appropriate UIDs/GIDs selected for the container (see above).
           This operation is potentially expensive, as it involves iterating
           through the full directory tree of the container. Besides actual
           file ownership, file ACLs are adjusted as well.

           This option is implied if --private-users=pick is used. This
           option has no effect if user namespacing is not used.

       -U
           If the kernel supports the user namespaces feature, equivalent to
           --private-users=pick --private-users-chown, otherwise equivalent
           to --private-users=no.

           Note that -U is the default if the systemd-nspawn@.service
           template unit file is used.

           Note: it is possible to undo the effect of --private-users-chown
           (or -U) on the file system by redoing the operation with the
           first UID of 0:

               systemd-nspawn ... --private-users=0 --private-users-chown

   Networking Options
       --private-network
           Disconnect networking of the container from the host. This makes
           all network interfaces unavailable in the container, with the
           exception of the loopback device and those specified with
           --network-interface= and configured with --network-veth. If this
           option is specified, the CAP_NET_ADMIN capability will be added
           to the set of capabilities the container retains. The latter may
           be disabled by using --drop-capability=. If this option is not
           specified (or implied by one of the options listed below), the
           container will have full access to the host network.

       --network-interface=
           Assign the specified network interface to the container. This
           will remove the specified interface from the calling namespace
           and place it in the container. When the container terminates, it
           is moved back to the host namespace. Note that
           --network-interface= implies --private-network. This option may
           be used more than once to add multiple network interfaces to the
           container.

       --network-macvlan=
           Create a "macvlan" interface of the specified Ethernet network
           interface and add it to the container. A "macvlan" interface is a
           virtual interface that adds a second MAC address to an existing
           physical Ethernet link. The interface in the container will be
           named after the interface on the host, prefixed with "mv-". Note
           that --network-macvlan= implies --private-network. This option
           may be used more than once to add multiple network interfaces to
           the container.

       --network-ipvlan=
           Create an "ipvlan" interface of the specified Ethernet network
           interface and add it to the container. An "ipvlan" interface is a
           virtual interface, similar to a "macvlan" interface, which uses
           the same MAC address as the underlying interface. The interface
           in the container will be named after the interface on the host,
           prefixed with "iv-". Note that --network-ipvlan= implies
           --private-network. This option may be used more than once to add
           multiple network interfaces to the container.

       -n, --network-veth
           Create a virtual Ethernet link ("veth") between host and
           container. The host side of the Ethernet link will be available
           as a network interface named after the container's name (as
           specified with --machine=), prefixed with "ve-". The container
           side of the Ethernet link will be named "host0". The
           --network-veth option implies --private-network.

           Note that systemd-networkd.service(8) includes by default a
           network file /usr/lib/systemd/network/80-container-ve.network
           matching the host-side interfaces created this way, which
           contains settings to enable automatic address provisioning on the
           created virtual link via DHCP, as well as automatic IP routing
           onto the host's external network interfaces. It also contains
           /usr/lib/systemd/network/80-container-host0.network matching the
           container-side interface created this way, containing settings to
           enable client side address assignment via DHCP. In case
           systemd-networkd is running on both the host and inside the
           container, automatic IP communication from the container to the
           host is thus available, with further connectivity to the external
           network.

           Note that --network-veth is the default if the
           systemd-nspawn@.service template unit file is used.

           Note that on Linux network interface names may have a length of
           15 characters at maximum, while container names may have a length
           up to 64 characters. As this option derives the host-side
           interface name from the container name the name is possibly
           truncated. Thus, care needs to be taken to ensure that interface
           names remain unique in this case, or even better container names
           are generally not chosen longer than 12 characters, to avoid the
           truncation. If the name is truncated, systemd-nspawn will
           automatically append a 4-digit hash value to the name to reduce
           the chance of collisions. However, the hash algorithm is not
           collision-free. (See systemd.net-naming-scheme(7) for details on
           older naming algorithms for this interface). Alternatively, the
           --network-veth-extra= option may be used, which allows free
           configuration of the host-side interface name independently of
           the container name — but might require a bit more additional
           configuration in case bridging in a fashion similar to
           --network-bridge= is desired.

       --network-veth-extra=
           Adds an additional virtual Ethernet link between host and
           container. Takes a colon-separated pair of host interface name
           and container interface name. The latter may be omitted in which
           case the container and host sides will be assigned the same name.
           This switch is independent of --network-veth, and — in contrast —
           may be used multiple times, and allows configuration of the
           network interface names. Note that --network-bridge= has no
           effect on interfaces created with --network-veth-extra=.

       --network-bridge=
           Adds the host side of the Ethernet link created with
           --network-veth to the specified Ethernet bridge interface.
           Expects a valid network interface name of a bridge device as
           argument. Note that --network-bridge= implies --network-veth. If
           this option is used, the host side of the Ethernet link will use
           the "vb-" prefix instead of "ve-". Regardless of the used naming
           prefix the same network interface name length limits imposed by
           Linux apply, along with the complications this creates (for
           details see above).

       --network-zone=
           Creates a virtual Ethernet link ("veth") to the container and
           adds it to an automatically managed Ethernet bridge interface.
           The bridge interface is named after the passed argument, prefixed
           with "vz-". The bridge interface is automatically created when
           the first container configured for its name is started, and is
           automatically removed when the last container configured for its
           name exits. Hence, each bridge interface configured this way
           exists only as long as there's at least one container referencing
           it running. This option is very similar to --network-bridge=,
           besides this automatic creation/removal of the bridge device.

           This setting makes it easy to place multiple related containers
           on a common, virtual Ethernet-based broadcast domain, here called
           a "zone". Each container may only be part of one zone, but each
           zone may contain any number of containers. Each zone is
           referenced by its name. Names may be chosen freely (as long as
           they form valid network interface names when prefixed with
           "vz-"), and it is sufficient to pass the same name to the
           --network-zone= switch of the various concurrently running
           containers to join them in one zone.

           Note that systemd-networkd.service(8) includes by default a
           network file /usr/lib/systemd/network/80-container-vz.network
           matching the bridge interfaces created this way, which contains
           settings to enable automatic address provisioning on the created
           virtual network via DHCP, as well as automatic IP routing onto
           the host's external network interfaces. Using --network-zone= is
           hence in most cases fully automatic and sufficient to connect
           multiple local containers in a joined broadcast domain to the
           host, with further connectivity to the external network.

       --network-namespace-path=
           Takes the path to a file representing a kernel network namespace
           that the container shall run in. The specified path should refer
           to a (possibly bind-mounted) network namespace file, as exposed
           by the kernel below /proc/$PID/ns/net. This makes the container
           enter the given network namespace. One of the typical use cases
           is to give a network namespace under /run/netns created by
           ip-netns(8), for example,
           --network-namespace-path=/run/netns/foo. Note that this option
           cannot be used together with other network-related options, such
           as --private-network or --network-interface=.

       -p, --port=
           If private networking is enabled, maps an IP port on the host
           onto an IP port on the container. Takes a protocol specifier
           (either "tcp" or "udp"), separated by a colon from a host port
           number in the range 1 to 65535, separated by a colon from a
           container port number in the range from 1 to 65535. The protocol
           specifier and its separating colon may be omitted, in which case
           "tcp" is assumed. The container port number and its colon may be
           omitted, in which case the same port as the host port is implied.
           This option is only supported if private networking is used, such
           as with --network-veth, --network-zone= --network-bridge=.

   Security Options
       --capability=
           List one or more additional capabilities to grant the container.
           Takes a comma-separated list of capability names, see
           capabilities(7) for more information. Note that the following
           capabilities will be granted in any way: CAP_AUDIT_CONTROL,
           CAP_AUDIT_WRITE, CAP_CHOWN, CAP_DAC_OVERRIDE,
           CAP_DAC_READ_SEARCH, CAP_FOWNER, CAP_FSETID, CAP_IPC_OWNER,
           CAP_KILL, CAP_LEASE, CAP_LINUX_IMMUTABLE, CAP_MKNOD,
           CAP_NET_BIND_SERVICE, CAP_NET_BROADCAST, CAP_NET_RAW,
           CAP_SETFCAP, CAP_SETGID, CAP_SETPCAP, CAP_SETUID, CAP_SYS_ADMIN,
           CAP_SYS_BOOT, CAP_SYS_CHROOT, CAP_SYS_NICE, CAP_SYS_PTRACE,
           CAP_SYS_RESOURCE, CAP_SYS_TTY_CONFIG. Also CAP_NET_ADMIN is
           retained if --private-network is specified. If the special value
           "all" is passed, all capabilities are retained.

           If the special value of "help" is passed, the program will print
           known capability names and exit.

       --drop-capability=
           Specify one or more additional capabilities to drop for the
           container. This allows running the container with fewer
           capabilities than the default (see above).

           If the special value of "help" is passed, the program will print
           known capability names and exit.

       --no-new-privileges=
           Takes a boolean argument. Specifies the value of the
           PR_SET_NO_NEW_PRIVS flag for the container payload. Defaults to
           off. When turned on the payload code of the container cannot
           acquire new privileges, i.e. the "setuid" file bit as well as
           file system capabilities will not have an effect anymore. See
           prctl(2) for details about this flag.

       --system-call-filter=
           Alter the system call filter applied to containers. Takes a
           space-separated list of system call names or group names (the
           latter prefixed with "@", as listed by the syscall-filter command
           of systemd-analyze(1)). Passed system calls will be permitted.
           The list may optionally be prefixed by "~", in which case all
           listed system calls are prohibited. If this command line option
           is used multiple times the configured lists are combined. If both
           a positive and a negative list (that is one system call list
           without and one with the "~" prefix) are configured, the negative
           list takes precedence over the positive list. Note that
           systemd-nspawn always implements a system call whitelist (as
           opposed to a blacklist), and this command line option hence adds
           or removes entries from the default whitelist, depending on the
           "~" prefix. Note that the applied system call filter is also
           altered implicitly if additional capabilities are passed using
           the --capabilities=.

       -Z, --selinux-context=
           Sets the SELinux security context to be used to label processes
           in the container.

       -L, --selinux-apifs-context=
           Sets the SELinux security context to be used to label files in
           the virtual API file systems in the container.

   Resource Options
       --rlimit=
           Sets the specified POSIX resource limit for the container
           payload. Expects an assignment of the form "LIMIT=SOFT:HARD" or
           "LIMIT=VALUE", where LIMIT should refer to a resource limit type,
           such as RLIMIT_NOFILE or RLIMIT_NICE. The SOFT and HARD fields
           should refer to the numeric soft and hard resource limit values.
           If the second form is used, VALUE may specify a value that is
           used both as soft and hard limit. In place of a numeric value the
           special string "infinity" may be used to turn off resource
           limiting for the specific type of resource. This command line
           option may be used multiple times to control limits on multiple
           limit types. If used multiple times for the same limit type, the
           last use wins. For details about resource limits see
           setrlimit(2). By default resource limits for the container's init
           process (PID 1) are set to the same values the Linux kernel
           originally passed to the host init system. Note that some
           resource limits are enforced on resources counted per user, in
           particular RLIMIT_NPROC. This means that unless user namespacing
           is deployed (i.e.  --private-users= is used, see above), any
           limits set will be applied to the resource usage of the same user
           on all local containers as well as the host. This means
           particular care needs to be taken with these limits as they might
           be triggered by possibly less trusted code. Example:
           "--rlimit=RLIMIT_NOFILE=8192:16384".

       --oom-score-adjust=
           Changes the OOM ("Out Of Memory") score adjustment value for the
           container payload. This controls /proc/self/oom_score_adj which
           influences the preference with which this container is terminated
           when memory becomes scarce. For details see proc(5). Takes an
           integer in the range -1000...1000.

       --cpu-affinity=
           Controls the CPU affinity of the container payload. Takes a comma
           separated list of CPU numbers or number ranges (the latter's
           start and end value separated by dashes). See
           sched_setaffinity(2) for details.

       --personality=
           Control the architecture ("personality") reported by uname(2) in
           the container. Currently, only "x86" and "x86-64" are supported.
           This is useful when running a 32-bit container on a 64-bit host.
           If this setting is not used, the personality reported in the
           container is the same as the one reported on the host.

   Integration Options
       --resolv-conf=
           Configures how /etc/resolv.conf inside of the container shall be
           handled (i.e. DNS configuration synchronization from host to
           container). Takes one of "off", "copy-host", "copy-static",
           "copy-uplink", "copy-stub", "replace-host", "replace-static",
           "replace-uplink", "replace-stub", "bind-host", "bind-static",
           "bind-uplink", "bind-stub", "delete" or "auto".

           If set to "off" the /etc/resolv.conf file in the container is
           left as it is included in the image, and neither modified nor
           bind mounted over.

           If set to "copy-host", the /etc/resolv.conf file from the host is
           copied into the container, unless the file exists already and is
           not a regular file (e.g. a symlink). Similar, if "replace-host"
           is used the file is copied, replacing any existing inode,
           including symlinks. Similar, if "bind-host" is used, the file is
           bind mounted from the host into the container.

           If set to "copy-static", "replace-static" or "bind-static" the
           static resolv.conf file supplied with systemd-resolved.service(8)
           (specifically: /usr/lib/systemd/resolv.conf) is copied or bind
           mounted into the container.

           If set to "copy-uplink", "replace-uplink" or "bind-uplink" the
           uplink resolv.conf file managed by systemd-resolved.service
           (specifically: /run/systemd/resolve/resolv.conf) is copied or
           bind mounted into the container.

           If set to "copy-stub", "replace-stub" or "bind-stub" the stub
           resolv.conf file managed by systemd-resolved.service
           (specifically: /run/systemd/resolve/stub-resolv.conf) is copied
           or bind mounted into the container.

           If set to "delete" the /etc/resolv.conf file in the container is
           deleted if it exists.

           Finally, if set to "auto" the file is left as it is if private
           networking is turned on (see --private-network). Otherwise, if
           systemd-resolved.service is connectible its stub resolv.conf file
           is used, and if not the host's /etc/resolv.conf file is used. In
           the latter cases the file is copied if the image is writable, and
           bind mounted otherwise.

           It's recommended to use "copy-..."  or "replace-..."  if the
           container shall be able to make changes to the DNS configuration
           on its own, deviating from the host's settings. Otherwise "bind"
           is preferable, as it means direct changes to /etc/resolv.conf in
           the container are not allowed, as it is a read-only bind mount
           (but note that if the container has enough privileges, it might
           simply go ahead and unmount the bind mount anyway). Note that
           both if the file is bind mounted and if it is copied no further
           propagation of configuration is generally done after the one-time
           early initialization (this is because the file is usually updated
           through copying and renaming). Defaults to "auto".

       --timezone=
           Configures how /etc/localtime inside of the container (i.e. local
           timezone synchronization from host to container) shall be
           handled. Takes one of "off", "copy", "bind", "symlink", "delete"
           or "auto". If set to "off" the /etc/localtime file in the
           container is left as it is included in the image, and neither
           modified nor bind mounted over. If set to "copy" the
           /etc/localtime file of the host is copied into the container.
           Similar, if "bind" is used, it is bind mounted from the host into
           the container. If set to "symlink" a symlink from /etc/localtime
           in the container is created pointing to the matching the timezone
           file of the container that matches the timezone setting on the
           host. If set to "delete" the file in the container is deleted,
           should it exist. If set to "auto" and the /etc/localtime file of
           the host is a symlink, then "symlink" mode is used, and "copy"
           otherwise, except if the image is read-only in which case "bind"
           is used instead. Defaults to "auto".

       --link-journal=
           Control whether the container's journal shall be made visible to
           the host system. If enabled, allows viewing the container's
           journal files from the host (but not vice versa). Takes one of
           "no", "host", "try-host", "guest", "try-guest", "auto". If "no",
           the journal is not linked. If "host", the journal files are
           stored on the host file system (beneath
           /var/log/journal/machine-id) and the subdirectory is bind-mounted
           into the container at the same location. If "guest", the journal
           files are stored on the guest file system (beneath
           /var/log/journal/machine-id) and the subdirectory is symlinked
           into the host at the same location.  "try-host" and "try-guest"
           do the same but do not fail if the host does not have persistent
           journaling enabled. If "auto" (the default), and the right
           subdirectory of /var/log/journal exists, it will be bind mounted
           into the container. If the subdirectory does not exist, no
           linking is performed. Effectively, booting a container once with
           "guest" or "host" will link the journal persistently if further
           on the default of "auto" is used.

           Note that --link-journal=try-guest is the default if the
           systemd-nspawn@.service template unit file is used.

       -j
           Equivalent to --link-journal=try-guest.

   Mount Options
       --bind=, --bind-ro=
           Bind mount a file or directory from the host into the container.
           Takes one of: a path argument — in which case the specified path
           will be mounted from the host to the same path in the container,
           or a colon-separated pair of paths — in which case the first
           specified path is the source in the host, and the second path is
           the destination in the container, or a colon-separated triple of
           source path, destination path and mount options. The source path
           may optionally be prefixed with a "+" character. If so, the
           source path is taken relative to the image's root directory. This
           permits setting up bind mounts within the container image. The
           source path may be specified as empty string, in which case a
           temporary directory below the host's /var/tmp directory is used.
           It is automatically removed when the container is shut down.
           Mount options are comma-separated and currently, only rbind and
           norbind are allowed, controlling whether to create a recursive or
           a regular bind mount. Defaults to "rbind". Backslash escapes are
           interpreted, so "\:" may be used to embed colons in either path.
           This option may be specified multiple times for creating multiple
           independent bind mount points. The --bind-ro= option creates
           read-only bind mounts.

           Note that when this option is used in combination with
           --private-users, the resulting mount points will be owned by the
           nobody user. That's because the mount and its files and
           directories continue to be owned by the relevant host users and
           groups, which do not exist in the container, and thus show up
           under the wildcard UID 65534 (nobody). If such bind mounts are
           created, it is recommended to make them read-only, using
           --bind-ro=.

       --inaccessible=
           Make the specified path inaccessible in the container. This
           over-mounts the specified path (which must exist in the
           container) with a file node of the same type that is empty and
           has the most restrictive access mode supported. This is an
           effective way to mask files, directories and other file system
           objects from the container payload. This option may be used more
           than once in case all specified paths are masked.

       --tmpfs=
           Mount a tmpfs file system into the container. Takes a single
           absolute path argument that specifies where to mount the tmpfs
           instance to (in which case the directory access mode will be
           chosen as 0755, owned by root/root), or optionally a
           colon-separated pair of path and mount option string that is used
           for mounting (in which case the kernel default for access mode
           and owner will be chosen, unless otherwise specified). Backslash
           escapes are interpreted in the path, so "\:" may be used to embed
           colons in the path.

           Note that this option cannot be used to replace the root file
           system of the container with a temporary file system. However,
           the --volatile= option described below provides similar
           functionality, with a focus on implementing stateless operating
           system images.

       --overlay=, --overlay-ro=
           Combine multiple directory trees into one overlay file system and
           mount it into the container. Takes a list of colon-separated
           paths to the directory trees to combine and the destination mount
           point.

           Backslash escapes are interpreted in the paths, so "\:" may be
           used to embed colons in the paths.

           If three or more paths are specified, then the last specified
           path is the destination mount point in the container, all paths
           specified before refer to directory trees on the host and are
           combined in the specified order into one overlay file system. The
           left-most path is hence the lowest directory tree, the
           second-to-last path the highest directory tree in the stacking
           order. If --overlay-ro= is used instead of --overlay=, a
           read-only overlay file system is created. If a writable overlay
           file system is created, all changes made to it are written to the
           highest directory tree in the stacking order, i.e. the
           second-to-last specified.

           If only two paths are specified, then the second specified path
           is used both as the top-level directory tree in the stacking
           order as seen from the host, as well as the mount point for the
           overlay file system in the container. At least two paths have to
           be specified.

           The source paths may optionally be prefixed with "+" character.
           If so they are taken relative to the image's root directory. The
           uppermost source path may also be specified as empty string, in
           which case a temporary directory below the host's /var/tmp is
           used. The directory is removed automatically when the container
           is shut down. This behaviour is useful in order to make read-only
           container directories writable while the container is running.
           For example, use the "--overlay=+/var::/var" option in order to
           automatically overlay a writable temporary directory on a
           read-only /var directory.

           For details about overlay file systems, see overlayfs.txt[5].
           Note that the semantics of overlay file systems are substantially
           different from normal file systems, in particular regarding
           reported device and inode information. Device and inode
           information may change for a file while it is being written to,
           and processes might see out-of-date versions of files at times.
           Note that this switch automatically derives the "workdir=" mount
           option for the overlay file system from the top-level directory
           tree, making it a sibling of it. It is hence essential that the
           top-level directory tree is not a mount point itself (since the
           working directory must be on the same file system as the top-most
           directory tree). Also note that the "lowerdir=" mount option
           receives the paths to stack in the opposite order of this switch.

           Note that this option cannot be used to replace the root file
           system of the container with an overlay file system. However, the
           --volatile= option described above provides similar
           functionality, with a focus on implementing stateless operating
           system images.

   Input/Output Options
       --console=MODE
           Configures how to set up standard input, output and error output
           for the container payload, as well as the /dev/console device for
           the container. Takes one of interactive, read-only, passive, or
           pipe. If interactive, a pseudo-TTY is allocated and made
           available as /dev/console in the container. It is then
           bi-directionally connected to the standard input and output
           passed to systemd-nspawn.  read-only is similar but only the
           output of the container is propagated and no input from the
           caller is read. If passive, a pseudo TTY is allocated, but it is
           not connected anywhere. Finally, in pipe mode no pseudo TTY is
           allocated, but the standard input, output and error output file
           descriptors passed to systemd-nspawn are passed on — as they are
           — to the container payload, see the following paragraph. Defaults
           to interactive if systemd-nspawn is invoked from a terminal, and
           read-only otherwise.

           In pipe mode, /dev/console will not exist in the container. This
           means that the container payload generally cannot be a full init
           system as init systems tend to require /dev/console to be
           available. On the other hand, in this mode container invocations
           can be used within shell pipelines. This is because intermediary
           pseudo TTYs do not permit independent bidirectional propagation
           of the end-of-file (EOF) condition, which is necessary for shell
           pipelines to work correctly.  Note that the pipe mode should be
           used carefully, as passing arbitrary file descriptors to less
           trusted container payloads might open up unwanted interfaces for
           access by the container payload. For example, if a passed file
           descriptor refers to a TTY of some form, APIs such as TIOCSTI may
           be used to synthesize input that might be used for escaping the
           container. Hence pipe mode should only be used if the payload is
           sufficiently trusted or when the standard input/output/error
           output file descriptors are known safe, for example pipes.

       --pipe, -P
           Equivalent to --console=pipe.

       --no-pager
           Do not pipe output into a pager.

       -h, --help
           Print a short help text and exit.

       --version
           Print a short version string and exit.

ENVIRONMENT         top

       $SYSTEMD_PAGER
           Pager to use when --no-pager is not given; overrides $PAGER. If
           neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known
           pager implementations are tried in turn, including less(1) and
           more(1), until one is found. If no pager implementation is
           discovered no pager is invoked. Setting this environment variable
           to an empty string or the value "cat" is equivalent to passing
           --no-pager.

       $SYSTEMD_LESS
           Override the options passed to less (by default "FRSXMK").

           Users might want to change two options in particular:

           K
               This option instructs the pager to exit immediately when
               Ctrl+C is pressed. To allow less to handle Ctrl+C itself to
               switch back to the pager command prompt, unset this option.

               If the value of $SYSTEMD_LESS does not include "K", and the
               pager that is invoked is less, Ctrl+C will be ignored by the
               executable, and needs to be handled by the pager.

           X
               This option instructs the pager to not send termcap
               initialization and deinitialization strings to the terminal.
               It is set by default to allow command output to remain
               visible in the terminal even after the pager exits.
               Nevertheless, this prevents some pager functionality from
               working, in particular paged output cannot be scrolled with
               the mouse.

           See less(1) for more discussion.

       $SYSTEMD_LESSCHARSET
           Override the charset passed to less (by default "utf-8", if the
           invoking terminal is determined to be UTF-8 compatible).

       $SYSTEMD_COLORS
           The value must be a boolean. Controls whether colorized output
           should be generated. This can be specified to override the
           decision that systemd makes based on $TERM and what the console
           is connected to.

       $SYSTEMD_URLIFY
           The value must be a boolean. Controls whether clickable links
           should be generated in the output for terminal emulators
           supporting this. This can be specified to override the decision
           that systemd makes based on $TERM and other conditions.

EXAMPLES         top

       Example 1. Download a Fedora image and start a shell in it

           # machinectl pull-raw --verify=no \
                 https://download.fedoraproject.org/pub/fedora/linux/releases/32/Cloud/x86_64/images/Fedora-Cloud-Base-32-1.6.x86_64.raw.xz \
                 Fedora-Cloud-Base-32-1.6.x86-64
           # systemd-nspawn -M Fedora-Cloud-Base-32-1.6.x86-64

       This downloads an image using machinectl(1) and opens a shell in it.

       Example 2. Build and boot a minimal Fedora distribution in a
       container

           # dnf -y --releasever=32 --installroot=/var/lib/machines/f32 \
                 --disablerepo='*' --enablerepo=fedora --enablerepo=updates install \
                 systemd passwd dnf fedora-release vim-minimal glibc-minimal-langpack
           # systemd-nspawn -bD /var/lib/machines/f32

       This installs a minimal Fedora distribution into the directory
       /var/lib/machines/f32 and then boots an OS in a namespace container
       in it. Because the installation is located underneath the standard
       /var/lib/machines/ directory, it is also possible to start the
       machine using systemd-nspawn -M f32.

       Example 3. Spawn a shell in a container of a minimal Debian unstable
       distribution

           # debootstrap unstable ~/debian-tree/
           # systemd-nspawn -D ~/debian-tree/

       This installs a minimal Debian unstable distribution into the
       directory ~/debian-tree/ and then spawns a shell in a namespace
       container in it.

       debootstrap supports Debian[7], Ubuntu[8], and Tanglu[9] out of the
       box, so the same command can be used to install any of those. For
       other distributions from the Debian family, a mirror has to be
       specified, see debootstrap(8).

       Example 4. Boot a minimal Arch Linux distribution in a container

           # pacstrap -c ~/arch-tree/ base
           # systemd-nspawn -bD ~/arch-tree/

       This installs a minimal Arch Linux distribution into the directory
       ~/arch-tree/ and then boots an OS in a namespace container in it.

       Example 5. Install the OpenSUSE Tumbleweed rolling distribution

           # zypper --root=/var/lib/machines/tumbleweed ar -c \
                 https://download.opensuse.org/tumbleweed/repo/oss tumbleweed
           # zypper --root=/var/lib/machines/tumbleweed refresh
           # zypper --root=/var/lib/machines/tumbleweed install --no-recommends \
                 systemd shadow zypper openSUSE-release vim
           # systemd-nspawn -M tumbleweed passwd root
           # systemd-nspawn -M tumbleweed -b

       Example 6. Boot into an ephemeral snapshot of the host system

           # systemd-nspawn -D / -xb

       This runs a copy of the host system in a snapshot which is removed
       immediately when the container exits. All file system changes made
       during runtime will be lost on shutdown, hence.

       Example 7. Run a container with SELinux sandbox security contexts

           # chcon system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -R /srv/container
           # systemd-nspawn -L system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 \
                 -Z system_u:system_r:svirt_lxc_net_t:s0:c0,c1 -D /srv/container /bin/sh

       Example 8. Run a container with an OSTree deployment

           # systemd-nspawn -b -i ~/image.raw \
                 --pivot-root=/ostree/deploy/$OS/deploy/$CHECKSUM:/sysroot \
                 --bind=+/sysroot/ostree/deploy/$OS/var:/var

EXIT STATUS         top

       The exit code of the program executed in the container is returned.

SEE ALSO         top

       systemd(1), systemd.nspawn(5), chroot(1), dnf(8), debootstrap(8),
       pacman(8), zypper(8), systemd.slice(5), machinectl(1), btrfs(8)

NOTES         top

        1. Container Interface
           https://systemd.io/CONTAINER_INTERFACE

        2. Discoverable Partitions Specification
           https://systemd.io/DISCOVERABLE_PARTITIONS

        3. OCI Runtime Specification
           https://github.com/opencontainers/runtime-spec/blob/master/spec.md

        4. OSTree
           https://ostree.readthedocs.io/en/latest/

        5. overlayfs.txt
           https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt

        6. Fedora
           https://getfedora.org

        7. Debian
           https://www.debian.org

        8. Ubuntu
           https://www.ubuntu.com

        9. Tanglu
           https://www.tanglu.org

       10. Arch Linux
           https://www.archlinux.org

       11. OpenSUSE Tumbleweed
           https://software.opensuse.org/distributions/tumbleweed

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a bug
       report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2020-06-09.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-06-09.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to man-pages@man7.org

systemd 245                                                SYSTEMD-NSPAWN(1)

Pages that refer to this page: machinectl(1)systemd-cgls(1)systemd-detect-virt(1)org.freedesktop.import1(5)systemd.nspawn(5)30-systemd-environment-d-generator(7)systemd.directives(7)systemd.index(7)systemd.net-naming-scheme(7)libnss_mymachines.so.2(8)nss-mymachines(8)systemd-importd(8)systemd-importd.service(8)systemd-machined(8)systemd-machined.service(8)