<?xml version='1.0'?> <!--*-nxml-*-->

<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<refentry id="systemd-nspawn"

xmlns:xi="http://www.w3.org/2001/XInclude">

<refentryinfo>

<title>systemd-nspawn</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>Lennart</firstname>

<surname>Poettering</surname>

<email>lennart@poettering.net</email>

</author>

</authorgroup>

</refentryinfo>

<refmeta>

<refentrytitle>systemd-nspawn</refentrytitle>

<manvolnum>1</manvolnum>

</refmeta>

<refnamediv>

<refname>systemd-nspawn</refname>

<refpurpose>Spawn a namespace container for debugging, testing and building</refpurpose>

</refnamediv>

<refsynopsisdiv>

<cmdsynopsis>

<command>systemd-nspawn</command>

<arg choice="opt" rep="repeat">OPTIONS</arg>

<arg choice="opt"><replaceable>COMMAND</replaceable>

<arg choice="opt" rep="repeat">ARGS</arg>

</arg>

</cmdsynopsis>

<cmdsynopsis>

<command>systemd-nspawn</command>

<arg choice="plain">-b</arg>

<arg choice="opt" rep="repeat">OPTIONS</arg>

<arg choice="opt" rep="repeat">ARGS</arg>

</cmdsynopsis>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para><command>systemd-nspawn</command> may be used to

run a command or OS in a light-weight namespace

container. In many ways it is similar to

<citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

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.</para>

<para><command>systemd-nspawn</command> limits access

to various kernel interfaces in the container to

read-only, such as <filename>/sys</filename>,

<filename>/proc/sys</filename> or

<filename>/sys/fs/selinux</filename>. 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.</para>

<para>Note that even though these security precautions

are taken <command>systemd-nspawn</command> is not

suitable for secure container setups. Many of the

security features may be circumvented and are hence

primarily useful to avoid accidental changes to the

host system from the container. The intended use of

this program is debugging and testing as well as

building of packages, distributions and software

involved with boot and systems management.</para>

<para>In contrast to

<citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry> <command>systemd-nspawn</command>

may be used to boot full Linux-based operating systems

in a container.</para>

<para>Use a tool like

<citerefentry project='die-net'><refentrytitle>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

or

<citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>

to set up an OS directory tree suitable as file system

hierarchy for <command>systemd-nspawn</command>

containers.</para>

<para>Note that <command>systemd-nspawn</command> will

mount file systems private to the container to

<filename>/dev</filename>,

<filename>/run</filename> and similar. These will

not be visible outside of the container, and their

contents will be lost when the container exits.</para>

<para>Note that running two

<command>systemd-nspawn</command> 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

<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s

<command>login</command> command to request an

additional login prompt in a running container.</para>

<para><command>systemd-nspawn</command> implements the

<ulink

url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container

Interface</ulink> specification.</para>

<para>As a safety check

<command>systemd-nspawn</command> will verify the

existence of <filename>/usr/lib/os-release</filename>

or <filename>/etc/os-release</filename> in the

container tree before starting the container (see

<citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>). 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.</para>

</refsect1>

<refsect1>

<title>Options</title>

<para>If option <option>-b</option> is specified, the

arguments are used as arguments for the init

binary. Otherwise, <replaceable>COMMAND</replaceable>

specifies the program to launch in the container, and

the remaining arguments are used as arguments for this

program. If <option>-b</option> is not used and no

arguments are specifed, a shell is launched in the

container.</para>

<para>The following options are understood:</para>

<variablelist>

<varlistentry>

<term><option>-D</option></term>

<term><option>--directory=</option></term>

<listitem><para>Directory to use as

file system root for the container.</para>

<para>If neither

<option>--directory=</option>, nor

<option>--image=</option> is specified

the directory is determined as

<filename>/var/lib/machines/</filename>

suffixed by the machine name as

specified with

<option>--machine=</option>. If

neither <option>--directory=</option>,

<option>--image=</option>, nor

<option>--machine=</option> are

specified, the current directory will

be used. May not be specified together

with

<option>--image=</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--template=</option></term>

<listitem><para>Directory or

<literal>btrfs</literal> subvolume to

use as template for the container's

root directory. If this is specified

and the container's root directory (as

configured by

<option>--directory=</option>) does

not yet exist it is created as

<literal>btrfs</literal> subvolume and

populated from this template

tree. Ideally, the specified template

path refers to the root of a

<literal>btrfs</literal> 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

<literal>btrfs</literal> subvolume (or

not even to a <literal>btrfs</literal>

file system at all), the tree is

copied, which can be substantially

more time-consuming. Note that if this

option is used the container's root

directory (in contrast to the template

directory!) must be located on a

<literal>btrfs</literal> file system,

so that the <literal>btrfs</literal>

subvolume may be created. May not be

specified together with

<option>--image=</option> or

<option>--ephemeral</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-x</option></term>

<term><option>--ephemeral</option></term>

<listitem><para>If specified, the

container is run with a temporary

<literal>btrfs</literal> snapshot of

its root directory (as configured with

<option>--directory=</option>), that

is removed immediately when the

container terminates. This option is

only supported if the root file system

is <literal>btrfs</literal>. May not

be specified together with

<option>--image=</option> or

<option>--template=</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-i</option></term>

<term><option>--image=</option></term>

<listitem><para>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:</para>

<itemizedlist>

<listitem><para>An MBR

partition table with a single

partition of type 0x83 that is

marked

bootable.</para></listitem>

<listitem><para>A GUID

partition table (GPT) with a single

partition of type

0fc63daf-8483-4772-8e79-3d69d8477de4.</para></listitem>

<listitem><para>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 <ulink

url="http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable

Partitions

Specification</ulink>.</para></listitem>

</itemizedlist>

<para>Any other partitions, such as

foreign partitions, swap partitions or

EFI system partitions are not

mounted. May not be specified together

with <option>--directory=</option>,

<option>--template=</option> or

<option>--ephemeral</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-b</option></term>

<term><option>--boot</option></term>

<listitem><para>Automatically search

for an init binary and invoke it

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 binary. This option may not be

combined with

<option>--share-system</option>.

</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-u</option></term>

<term><option>--user=</option></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-M</option></term>

<term><option>--machine=</option></term>

<listitem><para>Sets the machine name

for this container. This name may be

used to identify this container during

its runtime (for example in tools like

<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>

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

<option>--ephemeral</option> mode is

selected. If the root directory

selected is the host's root directory

the host's hostname is used as default

instead.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--uuid=</option></term>

<listitem><para>Set the specified UUID

for the container. The init system

will initialize

<filename>/etc/machine-id</filename>

from this if this file is not set yet.

</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--slice=</option></term>

<listitem><para>Make the container

part of the specified slice, instead

of the default

<filename>machine.slice</filename>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><option>--private-network</option></term>

<listitem><para>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

<option>--network-interface=</option>

and configured with

<option>--network-veth</option>. 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

<option>--drop-capability=</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--network-interface=</option></term>

<listitem><para>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

<option>--network-interface=</option>

implies

<option>--private-network</option>. This

option may be used more than once to

add multiple network interfaces to the

container.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--network-macvlan=</option></term>

<listitem><para>Create a

<literal>macvlan</literal> interface

of the specified Ethernet network

interface and add it to the

container. A

<literal>macvlan</literal> 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 <literal>mv-</literal>. Note that

<option>--network-macvlan=</option>

implies

<option>--private-network</option>. This

option may be used more than once to

add multiple network interfaces to the

container.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--network-ipvlan=</option></term>

<listitem><para>Create an

<literal>ipvlan</literal> interface

of the specified Ethernet network

interface and add it to the

container. An

<literal>ipvlan</literal> interface

is a virtual interface, similar to a

<literal>macvlan</literal> 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 <literal>iv-</literal>. Note that

<option>--network-ipvlan=</option>

implies

<option>--private-network</option>. This

option may be used more than once to

add multiple network interfaces to the

container.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-n</option></term>

<term><option>--network-veth</option></term>

<listitem><para>Create a virtual

Ethernet link

(<literal>veth</literal>) 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

<option>--machine=</option>), prefixed

with <literal>ve-</literal>. The

container side of the Ethernet

link will be named

<literal>host0</literal>. Note that

<option>--network-veth</option>

implies

<option>--private-network</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--network-bridge=</option></term>

<listitem><para>Adds the host side of

the Ethernet link created with

<option>--network-veth</option> to the

specified bridge. Note that

<option>--network-bridge=</option>

implies

<option>--network-veth</option>. If

this option is used, the host side of

the Ethernet link will use the

<literal>vb-</literal> prefix instead

of <literal>ve-</literal>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-p</option></term>

<term><option>--port=</option></term>

<listitem><para>If private networking

is enabled, maps an IP port on the

host onto an IP port on the

container. Takes a protocol specifier

(either <literal>tcp</literal> or

<literal>udp</literal>), 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

<literal>tcp</literal> is assumed.

The container port number and its

colon may be ommitted, in which case

the same port as the host port is

implied. This option is only supported

if private networking is used, such as

<option>--network-veth</option> or

<option>--network-bridge=</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-Z</option></term>

<term><option>--selinux-context=</option></term>

<listitem><para>Sets the SELinux

security context to be used to label

processes in the container.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><option>-L</option></term>

<term><option>--selinux-apifs-context=</option></term>

<listitem><para>Sets the SELinux security

context to be used to label files in

the virtual API file systems in the

container.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><option>--capability=</option></term>

<listitem><para>List one or more

additional capabilities to grant the

container. Takes a comma-separated

list of capability names, see

<citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>

for more information. Note that the

following capabilities will be granted

in any way: CAP_CHOWN,

CAP_DAC_OVERRIDE, CAP_DAC_READ_SEARCH,

CAP_FOWNER, CAP_FSETID, CAP_IPC_OWNER,

CAP_KILL, CAP_LEASE,

CAP_LINUX_IMMUTABLE,

CAP_NET_BIND_SERVICE,

CAP_NET_BROADCAST, CAP_NET_RAW,

CAP_SETGID, CAP_SETFCAP, CAP_SETPCAP,

CAP_SETUID, CAP_SYS_ADMIN,

CAP_SYS_CHROOT, CAP_SYS_NICE,

CAP_SYS_PTRACE, CAP_SYS_TTY_CONFIG,

CAP_SYS_RESOURCE, CAP_SYS_BOOT,

CAP_AUDIT_WRITE,

CAP_AUDIT_CONTROL. Also CAP_NET_ADMIN

is retained if

<option>--private-network</option> is

specified. If the special value

<literal>all</literal> is passed, all

capabilities are

retained.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--drop-capability=</option></term>

<listitem><para>Specify one or more

additional capabilities to drop for

the container. This allows running the

container with fewer capabilities than

the default (see above).</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--link-journal=</option></term>

<listitem><para>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

<literal>no</literal>,

<literal>host</literal>,

<literal>try-host</literal>,

<literal>guest</literal>,

<literal>try-guest</literal>,

<literal>auto</literal>. If

<literal>no</literal>, the journal is

not linked. If <literal>host</literal>,

the journal files are stored on the

host file system (beneath

<filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>)

and the subdirectory is bind-mounted

into the container at the same

location. If <literal>guest</literal>,

the journal files are stored on the

guest file system (beneath

<filename>/var/log/journal/<replaceable>machine-id</replaceable></filename>)

and the subdirectory is symlinked into the host

at the same location. <literal>try-host</literal>

and <literal>try-guest</literal> do the same

but do not fail if the host does not have

persistent journalling enabled.

If <literal>auto</literal> (the default),

and the right subdirectory of

<filename>/var/log/journal</filename>

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

<literal>guest</literal> or

<literal>host</literal> will link the

journal persistently if further on

the default of <literal>auto</literal>

is used.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-j</option></term>

<listitem><para>Equivalent to

<option>--link-journal=try-guest</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--read-only</option></term>

<listitem><para>Mount the root file

system read-only for the

container.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--bind=</option></term>

<term><option>--bind-ro=</option></term>

<listitem><para>Bind mount a file or

directory from the host into the

container. Either takes 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. The

<option>--bind-ro=</option> option

creates read-only bind

mounts.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--tmpfs=</option></term>

<listitem><para>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). This option is

particularly useful for mounting

directories such as

<filename>/var</filename> as tmpfs, to

allow state-less systems, in

particular when combined with

<option>--read-only</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--setenv=</option></term>

<listitem><para>Specifies an

environment variable assignment to

pass to the init process in the

container, in the format

<literal>NAME=VALUE</literal>. This

may be used to override the default

variables or to set additional

variables. This parameter may be used

more than once.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--share-system</option></term>

<listitem><para>Allows the container

to share certain system facilities

with the host. More specifically, this

turns off PID namespacing, UTS

namespacing and IPC namespacing, and

thus allows the guest to see and

interact more easily with processes

outside of the container. Note that

using this option makes it impossible

to start up a full Operating System in

the container, as an init system

cannot operate in this mode. It is

only useful to run specific programs

or applications this way, without

involving an init system in the

container. This option implies

<option>--register=no</option>. This

option may not be combined with

<option>--boot</option>.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--register=</option></term>

<listitem><para>Controls whether the

container is registered with

<citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. Takes

a boolean argument, defaults to

<literal>yes</literal>. This option

should be enabled when the container

runs a full Operating System (more

specifically: an init system), and is

useful to ensure that the container is

accessible via

<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>

and shown by tools such as

<citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>. If

the container does not run an init

system, it is recommended to set this

option to <literal>no</literal>. Note

that <option>--share-system</option>

implies

<option>--register=no</option>.

</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--keep-unit</option></term>

<listitem><para>Instead of creating a

transient scope unit to run the

container in, simply register the

service or scope unit

<command>systemd-nspawn</command> has

been invoked in with

<citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>. This

has no effect if

<option>--register=no</option> is

used. This switch should be used if

<command>systemd-nspawn</command> is

invoked from within a service unit,

and the service unit's sole purpose

is to run a single

<command>systemd-nspawn</command>

container. This option is not

available if run from a user

session.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--personality=</option></term>

<listitem><para>Control the

architecture ("personality") reported

by

<citerefentry><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry>

in the container. Currently, only

<literal>x86</literal> and

<literal>x86-64</literal> 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.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>-q</option></term>

<term><option>--quiet</option></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><option>--volatile</option><replaceable>=MODE</replaceable></term>

<listitem><para>Boots the container in

volatile mode. When no mode parameter

is passed or when mode is specified as

<literal>yes</literal> full volatile

mode is enabled. This means the root

directory is mounted as mostly

unpopulated <literal>tmpfs</literal>

instance, and

<filename>/usr</filename> from the OS

tree is mounted into it, read-only

(the system thus starts up with

read-only OS resources, but pristine

state and configuration, any changes

to the either are lost on

shutdown). When the mode parameter is

specified as <literal>state</literal>

the OS tree is mounted read-only, but

<filename>/var</filename> is mounted

as <literal>tmpfs</literal> instance

into it (the system thus starts up

with read-only OS resources and

configuration, but pristine state, any

changes to the latter are lost on

shutdown). When the mode parameter is

specified as <literal>no</literal>

(the default) the whole OS tree is

made available writable.</para>

<para>Note that setting this to

<literal>yes</literal> or

<literal>state</literal> will only

work correctly with operating systems

in the container that can boot up with

only <filename>/usr</filename>

mounted, and are able to populate

<filename>/var</filename>

automatically, as

needed.</para></listitem>

</varlistentry>

<xi:include href="standard-options.xml" xpointer="help" />

<xi:include href="standard-options.xml" xpointer="version" />

</variablelist>

</refsect1>

<refsect1>

<title>Examples</title>

<example>

<title>Download a Fedora image and start a shell in it</title>

<programlisting># machinectl pull-raw --verify=no http://ftp.halifax.rwth-aachen.de/fedora/linux/releases/21/Cloud/Images/x86_64/Fedora-Cloud-Base-20141203-21.x86_64.raw.xz

# systemd-nspawn -M Fedora-Cloud-Base-20141203-21</programlisting>

<para>This downloads an image using <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> and opens a shell in it.</para>

</example>

<example>

<title>Build and boot a minimal Fedora distribution in a container</title>

<programlisting># yum -y --releasever=21 --nogpg --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora install systemd passwd yum fedora-release vim-minimal

# systemd-nspawn -bD /srv/mycontainer</programlisting>

<para>This installs a minimal Fedora distribution into

the directory <filename noindex='true'>/srv/mycontainer/</filename> and

then boots an OS in a namespace container in

it.</para>

</example>

<example>

<title>Spawn a shell in a container of a minimal Debian unstable distribution</title>

<programlisting># debootstrap --arch=amd64 unstable ~/debian-tree/

# systemd-nspawn -D ~/debian-tree/</programlisting>

<para>This installs a minimal Debian unstable

distribution into the directory

<filename>~/debian-tree/</filename> and then spawns a

shell in a namespace container in it.</para>

</example>

<example>

<title>Boot a minimal Arch Linux distribution in a container</title>

<programlisting># pacstrap -c -d ~/arch-tree/ base

# systemd-nspawn -bD ~/arch-tree/</programlisting>

<para>This installs a mimimal Arch Linux distribution into

the directory <filename>~/arch-tree/</filename> and then

boots an OS in a namespace container in it.</para>

</example>

<example>

<title>Boot into an ephemeral <literal>btrfs</literal> snapshot of the host system</title>

<programlisting># systemd-nspawn -D / -xb</programlisting>

<para>This runs a copy of the host system in a

<literal>btrfs</literal> snapshot which is

removed immediately when the container

exits. All file system changes made during

runtime will be lost on shutdown,

hence.</para>

</example>

<example>

<title>Run a container with SELinux sandbox security contexts</title>

<programlisting># 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</programlisting>

</example>

</refsect1>

<refsect1>

<title>Exit status</title>

<para>The exit code of the program executed in the

container is returned.</para>

</refsect1>

<refsect1>

<title>See Also</title>

<para>

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry project='archlinux'><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>