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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ENVIRONMENT | EXAMPLES | EXIT STATUS | SEE ALSO | NOTES | COLOPHON |
SYSTEMD-NSPAWN(1) systemd-nspawn SYSTEMD-NSPAWN(1)
systemd-nspawn - Spawn a command or OS in a light-weight container
systemd-nspawn [OPTIONS...] [COMMAND [ARGS...]]
systemd-nspawn --boot [OPTIONS...] [ARGS...]
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.
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.
Single file system images (i.e. file systems without a
surrounding partition table) can be opened using dm-verity if the
integrity data is passed using the --root-hash= and
--verity-data= (and optionally --root-hash-sig=) options.
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 (except if the image has the .raw
suffix, in which case the root hash file must not have it in its
name), the root hash is read from it and automatically used, also
as formatted hexadecimal characters.
--root-hash-sig=
Takes a PKCS7 formatted binary signature of the --root-hash=
option as a path to a DER encoded signature file or as an ASCII
base64 string encoding of the DER encoded signature, prefixed by
"base64:". The dm-verity volume will only be opened if the
signature of the root hash hex string is valid and done by a
public key present in the kernel keyring. If this option is not
specified, but a file with the .roothash.p7s suffix is found next
to the image file, bearing otherwise the same name (except if the
image has the .raw suffix, in which case the signature file must
not have it in its name), the signature is read from it and
automatically used.
--verity-data=
Takes the path to a data integrity (dm-verity) file. This option
enables data integrity checks using dm-verity, if a root-hash is
passed and if the used image itself does not contains the
integrity data. The integrity data must be matched by the root
hash. If this option is not specified, but a file with the
.verity suffix is found next to the image file, bearing otherwise
the same name (except if the image has the .raw suffix, in which
case the verity data file must not have it in its name), the
verity data is read from it and automatically used.
--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 allow list (as
opposed to a deny list!), and this command line option hence adds
or removes entries from the default allow list, 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 running its stub resolv.conf file is
used, and if not the host's /etc/resolv.conf file. 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.
Similarly, if "bind" is used, the file is bind mounted from the
host into the container. If set to "symlink", a symlink is
created pointing from /etc/localtime in the container to the
timezone file in 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.
$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.
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 that OS in a namespace
container. 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 from this image in a
namespace container.
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
The exit code of the program executed in the container is returned.
systemd(1), systemd.nspawn(5), chroot(1), dnf(8), debootstrap(8),
pacman(8), zypper(8), systemd.slice(5), machinectl(1), btrfs(8)
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
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 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-11.) 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 246 SYSTEMD-NSPAWN(1)
Pages that refer to this page: journalctl(1) , machinectl(1) , systemd-cgls(1) , systemd-detect-virt(1) , systemd-firstboot(1) , systemd-firstboot.service(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) , libnss_systemd.so.2(8) , nss-mymachines(8) , nss-systemd(8) , systemd-importd(8) , systemd-importd.service(8) , systemd-machined(8) , systemd-machined.service(8) , systemd-sysusers(8) , systemd-sysusers.service(8) , systemd-tmpfiles(8) , systemd-tmpfiles-clean.service(8) , systemd-tmpfiles-clean.timer(8) , systemd-tmpfiles-setup-dev.service(8) , systemd-tmpfiles-setup.service(8)