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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>systemd-nspawn</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
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</style><a href="index.html">Index </a>·
<a href="systemd.directives.html">Directives </a>·
<a href="../python-systemd/index.html">Python </a>·
<a href="../libudev/index.html">libudev </a>·
<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</span><hr><div class="refentry"><a name="systemd-nspawn"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>systemd-nspawn — Spawn a namespace container for debugging, testing and building</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">systemd-nspawn</code> [OPTIONS...] [<em class="replaceable"><code>COMMAND</code></em>
[ARGS...]
]</p></div><div class="cmdsynopsis"><p><code class="command">systemd-nspawn</code> -b [OPTIONS...] [ARGS...]</p></div></div><div class="refsect1"><a name="idm140120374671376"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description"></a></h2><p><span class="command"><strong>systemd-nspawn</strong></span> may be used to run a
command or OS in a light-weight namespace container. In many ways
it is similar to
<a href="http://man7.org/linux/man-pages/man1/chroot.1.html"><span class="citerefentry"><span class="refentrytitle">chroot</span>(1)</span></a>,
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.</p><p><span class="command"><strong>systemd-nspawn</strong></span> limits access to various
kernel interfaces in the container to read-only, such as
<code class="filename">/sys</code>, <code class="filename">/proc/sys</code> or
<code class="filename">/sys/fs/selinux</code>. 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.</p><p>Note that even though these security precautions are taken
<span class="command"><strong>systemd-nspawn</strong></span> 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.</p><p>In contrast to
<a href="http://man7.org/linux/man-pages/man1/chroot.1.html"><span class="citerefentry"><span class="refentrytitle">chroot</span>(1)</span></a> <span class="command"><strong>systemd-nspawn</strong></span>
may be used to boot full Linux-based operating systems in a
container.</p><p>Use a tool like
<a href="https://www.mankier.com/8/dnf"><span class="citerefentry"><span class="refentrytitle">dnf</span>(8)</span></a>,
<a href="http://linux.die.net/man/8/yum"><span class="citerefentry"><span class="refentrytitle">yum</span>(8)</span></a>,
<a href="http://linux.die.net/man/8/debootstrap"><span class="citerefentry"><span class="refentrytitle">debootstrap</span>(8)</span></a>,
or
<a href="https://www.archlinux.org/pacman/pacman.8.html"><span class="citerefentry"><span class="refentrytitle">pacman</span>(8)</span></a>
to set up an OS directory tree suitable as file system hierarchy
for <span class="command"><strong>systemd-nspawn</strong></span> containers.</p><p>Note that <span class="command"><strong>systemd-nspawn</strong></span> will mount file
systems private to the container to <code class="filename">/dev</code>,
<code class="filename">/run</code> and similar. These will not be visible
outside of the container, and their contents will be lost when the
container exits.</p><p>Note that running two <span class="command"><strong>systemd-nspawn</strong></span>
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
<a href="machinectl.html"><span class="citerefentry"><span class="refentrytitle">machinectl</span>(1)</span></a>'s
<span class="command"><strong>login</strong></span> command to request an additional login
prompt in a running container.</p><p><span class="command"><strong>systemd-nspawn</strong></span> implements the
<a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface" target="_top">Container
Interface</a> specification.</p><p>As a safety check <span class="command"><strong>systemd-nspawn</strong></span> will
verify the existence of <code class="filename">/usr/lib/os-release</code>
or <code class="filename">/etc/os-release</code> in the container tree
before starting the container (see
<a href="os-release.html"><span class="citerefentry"><span class="refentrytitle">os-release</span>(5)</span></a>).
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.</p></div><div class="refsect1"><a name="idm140120378540128"></a><h2 id="Options">Options<a class="headerlink" title="Permalink to this headline" href="#Options"></a></h2><p>If option <code class="option">-b</code> is specified, the arguments
are used as arguments for the init binary. Otherwise,
<em class="replaceable"><code>COMMAND</code></em> specifies the program to launch
in the container, and the remaining arguments are used as
arguments for this program. If <code class="option">-b</code> is not used and
no arguments are specifed, a shell is launched in the
container.</p><p>The following options are understood:</p><div class="variablelist"><dl class="variablelist"><dt id="-D"><span class="term"><code class="option">-D</code>, </span><span class="term"><code class="option">--directory=</code></span><a class="headerlink" title="Permalink to this term" href="#-D"></a></dt><dd><p>Directory to use as file system root for the
container.</p><p>If neither <code class="option">--directory=</code>, nor
<code class="option">--image=</code> is specified the directory is
determined as <code class="filename">/var/lib/machines/</code> suffixed
by the machine name as specified with
<code class="option">--machine=</code>. If neither
<code class="option">--directory=</code>, <code class="option">--image=</code>, nor
<code class="option">--machine=</code> are specified, the current
directory will be used. May not be specified together with
<code class="option">--image=</code>.</p></dd><dt id="--template="><span class="term"><code class="option">--template=</code></span><a class="headerlink" title="Permalink to this term" href="#--template="></a></dt><dd><p>Directory or "<code class="literal">btrfs</code>"
subvolume to use as template for the container's root
directory. If this is specified and the container's root
directory (as configured by <code class="option">--directory=</code>)
does not yet exist it is created as "<code class="literal">btrfs</code>"
subvolume and populated from this template tree. Ideally, the
specified template path refers to the root of a
"<code class="literal">btrfs</code>" 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 "<code class="literal">btrfs</code>" subvolume (or
not even to a "<code class="literal">btrfs</code>" 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 "<code class="literal">btrfs</code>" file
system, so that the "<code class="literal">btrfs</code>" subvolume may be
created. May not be specified together with
<code class="option">--image=</code> or
<code class="option">--ephemeral</code>.</p></dd><dt id="-x"><span class="term"><code class="option">-x</code>, </span><span class="term"><code class="option">--ephemeral</code></span><a class="headerlink" title="Permalink to this term" href="#-x"></a></dt><dd><p>If specified, the container is run with a
temporary "<code class="literal">btrfs</code>" snapshot of its root
directory (as configured with <code class="option">--directory=</code>),
that is removed immediately when the container terminates.
This option is only supported if the root file system is
"<code class="literal">btrfs</code>". May not be specified together with
<code class="option">--image=</code> or
<code class="option">--template=</code>.</p></dd><dt id="-i"><span class="term"><code class="option">-i</code>, </span><span class="term"><code class="option">--image=</code></span><a class="headerlink" title="Permalink to this term" href="#-i"></a></dt><dd><p>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:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>An MBR partition table with a single
partition of type 0x83 that is marked
bootable.</p></li><li class="listitem"><p>A GUID partition table (GPT) with a single
partition of type
0fc63daf-8483-4772-8e79-3d69d8477de4.</p></li><li class="listitem"><p>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 <a class="ulink" href="http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/" target="_top">Discoverable
Partitions Specification</a>.</p></li></ul></div><p>Any other partitions, such as foreign partitions, swap
partitions or EFI system partitions are not mounted. May not
be specified together with <code class="option">--directory=</code>,
<code class="option">--template=</code> or
<code class="option">--ephemeral</code>.</p></dd><dt id="-b"><span class="term"><code class="option">-b</code>, </span><span class="term"><code class="option">--boot</code></span><a class="headerlink" title="Permalink to this term" href="#-b"></a></dt><dd><p>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 <code class="option">--share-system</code>.
</p></dd><dt id="-u"><span class="term"><code class="option">-u</code>, </span><span class="term"><code class="option">--user=</code></span><a class="headerlink" title="Permalink to this term" href="#-u"></a></dt><dd><p>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.</p></dd><dt id="-M"><span class="term"><code class="option">-M</code>, </span><span class="term"><code class="option">--machine=</code></span><a class="headerlink" title="Permalink to this term" href="#-M"></a></dt><dd><p>Sets the machine name for this container. This
name may be used to identify this container during its runtime
(for example in tools like
<a href="machinectl.html"><span class="citerefentry"><span class="refentrytitle">machinectl</span>(1)</span></a>
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 <code class="option">--ephemeral</code>
mode is selected. If the root directory selected is the host's
root directory the host's hostname is used as default
instead.</p></dd><dt id="--uuid="><span class="term"><code class="option">--uuid=</code></span><a class="headerlink" title="Permalink to this term" href="#--uuid="></a></dt><dd><p>Set the specified UUID for the container. The
init system will initialize
<code class="filename">/etc/machine-id</code> from this if this file is
not set yet. </p></dd><dt id="--slice="><span class="term"><code class="option">--slice=</code></span><a class="headerlink" title="Permalink to this term" href="#--slice="></a></dt><dd><p>Make the container part of the specified
slice, instead of the default
<code class="filename">machine.slice</code>.</p></dd><dt id="--private-network"><span class="term"><code class="option">--private-network</code></span><a class="headerlink" title="Permalink to this term" href="#--private-network"></a></dt><dd><p>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 <code class="option">--network-interface=</code> and
configured with <code class="option">--network-veth</code>. 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
<code class="option">--drop-capability=</code>.</p></dd><dt id="--network-interface="><span class="term"><code class="option">--network-interface=</code></span><a class="headerlink" title="Permalink to this term" href="#--network-interface="></a></dt><dd><p>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 <code class="option">--network-interface=</code> implies
<code class="option">--private-network</code>. This option may be used
more than once to add multiple network interfaces to the
container.</p></dd><dt id="--network-macvlan="><span class="term"><code class="option">--network-macvlan=</code></span><a class="headerlink" title="Permalink to this term" href="#--network-macvlan="></a></dt><dd><p>Create a "<code class="literal">macvlan</code>" interface
of the specified Ethernet network interface and add it to the
container. A "<code class="literal">macvlan</code>" 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
"<code class="literal">mv-</code>". Note that
<code class="option">--network-macvlan=</code> implies
<code class="option">--private-network</code>. This option may be used
more than once to add multiple network interfaces to the
container.</p></dd><dt id="--network-ipvlan="><span class="term"><code class="option">--network-ipvlan=</code></span><a class="headerlink" title="Permalink to this term" href="#--network-ipvlan="></a></dt><dd><p>Create an "<code class="literal">ipvlan</code>" interface
of the specified Ethernet network interface and add it to the
container. An "<code class="literal">ipvlan</code>" interface is a virtual
interface, similar to a "<code class="literal">macvlan</code>" 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 "<code class="literal">iv-</code>".
Note that <code class="option">--network-ipvlan=</code> implies
<code class="option">--private-network</code>. This option may be used
more than once to add multiple network interfaces to the
container.</p></dd><dt id="-n"><span class="term"><code class="option">-n</code>, </span><span class="term"><code class="option">--network-veth</code></span><a class="headerlink" title="Permalink to this term" href="#-n"></a></dt><dd><p>Create a virtual Ethernet link
("<code class="literal">veth</code>") 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
<code class="option">--machine=</code>), prefixed with
"<code class="literal">ve-</code>". The container side of the Ethernet
link will be named "<code class="literal">host0</code>". Note that
<code class="option">--network-veth</code> implies
<code class="option">--private-network</code>.</p></dd><dt id="--network-bridge="><span class="term"><code class="option">--network-bridge=</code></span><a class="headerlink" title="Permalink to this term" href="#--network-bridge="></a></dt><dd><p>Adds the host side of the Ethernet link
created with <code class="option">--network-veth</code> to the specified
bridge. Note that <code class="option">--network-bridge=</code> implies
<code class="option">--network-veth</code>. If this option is used, the
host side of the Ethernet link will use the
"<code class="literal">vb-</code>" prefix instead of
"<code class="literal">ve-</code>".</p></dd><dt id="-p"><span class="term"><code class="option">-p</code>, </span><span class="term"><code class="option">--port=</code></span><a class="headerlink" title="Permalink to this term" href="#-p"></a></dt><dd><p>If private networking is enabled, maps an IP
port on the host onto an IP port on the container. Takes a
protocol specifier (either "<code class="literal">tcp</code>" or
"<code class="literal">udp</code>"), 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 "<code class="literal">tcp</code>" 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
<code class="option">--network-veth</code> or
<code class="option">--network-bridge=</code>.</p></dd><dt id="-Z"><span class="term"><code class="option">-Z</code>, </span><span class="term"><code class="option">--selinux-context=</code></span><a class="headerlink" title="Permalink to this term" href="#-Z"></a></dt><dd><p>Sets the SELinux security context to be used
to label processes in the container.</p></dd><dt id="-L"><span class="term"><code class="option">-L</code>, </span><span class="term"><code class="option">--selinux-apifs-context=</code></span><a class="headerlink" title="Permalink to this term" href="#-L"></a></dt><dd><p>Sets the SELinux security context to be used
to label files in the virtual API file systems in the
container.</p></dd><dt id="--capability="><span class="term"><code class="option">--capability=</code></span><a class="headerlink" title="Permalink to this term" href="#--capability="></a></dt><dd><p>List one or more additional capabilities to
grant the container. Takes a comma-separated list of
capability names, see
<a href="http://man7.org/linux/man-pages/man7/capabilities.7.html"><span class="citerefentry"><span class="refentrytitle">capabilities</span>(7)</span></a>
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 <code class="option">--private-network</code> is specified.
If the special value "<code class="literal">all</code>" is passed, all
capabilities are retained.</p></dd><dt id="--drop-capability="><span class="term"><code class="option">--drop-capability=</code></span><a class="headerlink" title="Permalink to this term" href="#--drop-capability="></a></dt><dd><p>Specify one or more additional capabilities to
drop for the container. This allows running the container with
fewer capabilities than the default (see
above).</p></dd><dt id="--link-journal="><span class="term"><code class="option">--link-journal=</code></span><a class="headerlink" title="Permalink to this term" href="#--link-journal="></a></dt><dd><p>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 "<code class="literal">no</code>",
"<code class="literal">host</code>", "<code class="literal">try-host</code>",
"<code class="literal">guest</code>", "<code class="literal">try-guest</code>",
"<code class="literal">auto</code>". If "<code class="literal">no</code>", the journal
is not linked. If "<code class="literal">host</code>", the journal files
are stored on the host file system (beneath
<code class="filename">/var/log/journal/<em class="replaceable"><code>machine-id</code></em></code>)
and the subdirectory is bind-mounted into the container at the
same location. If "<code class="literal">guest</code>", the journal files
are stored on the guest file system (beneath
<code class="filename">/var/log/journal/<em class="replaceable"><code>machine-id</code></em></code>)
and the subdirectory is symlinked into the host at the same
location. "<code class="literal">try-host</code>" and
"<code class="literal">try-guest</code>" do the same but do not fail if
the host does not have persistent journalling enabled. If
"<code class="literal">auto</code>" (the default), and the right
subdirectory of <code class="filename">/var/log/journal</code> 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
"<code class="literal">guest</code>" or "<code class="literal">host</code>" will link
the journal persistently if further on the default of
"<code class="literal">auto</code>" is used.</p></dd><dt id="-j"><span class="term"><code class="option">-j</code></span><a class="headerlink" title="Permalink to this term" href="#-j"></a></dt><dd><p>Equivalent to
<code class="option">--link-journal=try-guest</code>.</p></dd><dt id="--read-only"><span class="term"><code class="option">--read-only</code></span><a class="headerlink" title="Permalink to this term" href="#--read-only"></a></dt><dd><p>Mount the root file system read-only for the
container.</p></dd><dt id="--bind="><span class="term"><code class="option">--bind=</code>, </span><span class="term"><code class="option">--bind-ro=</code></span><a class="headerlink" title="Permalink to this term" href="#--bind="></a></dt><dd><p>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 <code class="option">--bind-ro=</code> option creates
read-only bind mounts.</p></dd><dt id="--tmpfs="><span class="term"><code class="option">--tmpfs=</code></span><a class="headerlink" title="Permalink to this term" href="#--tmpfs="></a></dt><dd><p>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 <code class="filename">/var</code> as
tmpfs, to allow state-less systems, in particular when
combined with <code class="option">--read-only</code>.</p></dd><dt id="--setenv="><span class="term"><code class="option">--setenv=</code></span><a class="headerlink" title="Permalink to this term" href="#--setenv="></a></dt><dd><p>Specifies an environment variable assignment
to pass to the init process in the container, in the format
"<code class="literal">NAME=VALUE</code>". This may be used to override
the default variables or to set additional variables. This
parameter may be used more than once.</p></dd><dt id="--share-system"><span class="term"><code class="option">--share-system</code></span><a class="headerlink" title="Permalink to this term" href="#--share-system"></a></dt><dd><p>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 <code class="option">--register=no</code>.
This option may not be combined with
<code class="option">--boot</code>.</p></dd><dt id="--register="><span class="term"><code class="option">--register=</code></span><a class="headerlink" title="Permalink to this term" href="#--register="></a></dt><dd><p>Controls whether the container is registered
with
<a href="systemd-machined.html"><span class="citerefentry"><span class="refentrytitle">systemd-machined</span>(8)</span></a>.
Takes a boolean argument, defaults to "<code class="literal">yes</code>".
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
<a href="machinectl.html"><span class="citerefentry"><span class="refentrytitle">machinectl</span>(1)</span></a>
and shown by tools such as
<a href="http://man7.org/linux/man-pages/man1/ps.1.html"><span class="citerefentry"><span class="refentrytitle">ps</span>(1)</span></a>.
If the container does not run an init system, it is
recommended to set this option to "<code class="literal">no</code>". Note
that <code class="option">--share-system</code> implies
<code class="option">--register=no</code>. </p></dd><dt id="--keep-unit"><span class="term"><code class="option">--keep-unit</code></span><a class="headerlink" title="Permalink to this term" href="#--keep-unit"></a></dt><dd><p>Instead of creating a transient scope unit to
run the container in, simply register the service or scope
unit <span class="command"><strong>systemd-nspawn</strong></span> has been invoked in
with
<a href="systemd-machined.html"><span class="citerefentry"><span class="refentrytitle">systemd-machined</span>(8)</span></a>.
This has no effect if <code class="option">--register=no</code> is used.
This switch should be used if
<span class="command"><strong>systemd-nspawn</strong></span> is invoked from within a
service unit, and the service unit's sole purpose is to run a
single <span class="command"><strong>systemd-nspawn</strong></span> container. This
option is not available if run from a user
session.</p></dd><dt id="--personality="><span class="term"><code class="option">--personality=</code></span><a class="headerlink" title="Permalink to this term" href="#--personality="></a></dt><dd><p>Control the architecture ("personality")
reported by
<a href="http://man7.org/linux/man-pages/man2/uname.2.html"><span class="citerefentry"><span class="refentrytitle">uname</span>(2)</span></a>
in the container. Currently, only "<code class="literal">x86</code>" and
"<code class="literal">x86-64</code>" 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.</p></dd><dt id="-q"><span class="term"><code class="option">-q</code>, </span><span class="term"><code class="option">--quiet</code></span><a class="headerlink" title="Permalink to this term" href="#-q"></a></dt><dd><p>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.</p></dd><dt id="--volatile=MODE"><span class="term"><code class="option">--volatile</code><em class="replaceable"><code>=MODE</code></em></span><a class="headerlink" title="Permalink to this term" href="#--volatile=MODE"></a></dt><dd><p>Boots the container in volatile mode. When no
mode parameter is passed or when mode is specified as
"<code class="literal">yes</code>" full volatile mode is enabled. This
means the root directory is mounted as mostly unpopulated
"<code class="literal">tmpfs</code>" instance, and
<code class="filename">/usr</code> 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 "<code class="literal">state</code>" the OS tree is
mounted read-only, but <code class="filename">/var</code> is mounted as
"<code class="literal">tmpfs</code>" 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
"<code class="literal">no</code>" (the default) the whole OS tree is made
available writable.</p><p>Note that setting this to "<code class="literal">yes</code>" or
"<code class="literal">state</code>" will only work correctly with
operating systems in the container that can boot up with only
<code class="filename">/usr</code> mounted, and are able to populate
<code class="filename">/var</code> automatically, as
needed.</p></dd><dt id="-h"><span class="term"><code class="option">-h</code>, </span><span class="term"><code class="option">--help</code></span><a class="headerlink" title="Permalink to this term" href="#-h"></a></dt><dd><p><a name="help-text"></a>Print a short help text and exit.
</p></dd><dt id="--version"><span class="term"><code class="option">--version</code></span><a class="headerlink" title="Permalink to this term" href="#--version"></a></dt><dd><p><a name="version-text"></a>Print a short version string and exit.</p></dd></dl></div></div><div class="refsect1"><a name="idm140120373477968"></a><h2 id="Examples">Examples<a class="headerlink" title="Permalink to this headline" href="#Examples"></a></h2><div class="example"><a name="idm140120373477328"></a><p class="title"><b>Example 1. Download a Fedora image and start a shell in it</b></p><div class="example-contents"><pre class="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</pre><p>This downloads an image using
<a href="machinectl.html"><span class="citerefentry"><span class="refentrytitle">machinectl</span>(1)</span></a>
and opens a shell in it.</p></div></div><br class="example-break"><div class="example"><a name="idm140120373474560"></a><p class="title"><b>Example 2. Build and boot a minimal Fedora distribution in a container</b></p><div class="example-contents"><pre class="programlisting"># dnf -y --releasever=21 --nogpg --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora install systemd passwd dnf fedora-release vim-minimal
# systemd-nspawn -bD /srv/mycontainer</pre><p>This installs a minimal Fedora distribution into the
directory <code class="filename">/srv/mycontainer/</code>
and then boots an OS in a namespace container in it.</p></div></div><br class="example-break"><div class="example"><a name="idm140120373471472"></a><p class="title"><b>Example 3. Spawn a shell in a container of a minimal Debian unstable distribution</b></p><div class="example-contents"><pre class="programlisting"># debootstrap --arch=amd64 unstable ~/debian-tree/
# systemd-nspawn -D ~/debian-tree/</pre><p>This installs a minimal Debian unstable distribution into
the directory <code class="filename">~/debian-tree/</code> and then
spawns a shell in a namespace container in it.</p></div></div><br class="example-break"><div class="example"><a name="idm140120373468720"></a><p class="title"><b>Example 4. Boot a minimal Arch Linux distribution in a container</b></p><div class="example-contents"><pre class="programlisting"># pacstrap -c -d ~/arch-tree/ base
# systemd-nspawn -bD ~/arch-tree/</pre><p>This installs a mimimal Arch Linux distribution into the
directory <code class="filename">~/arch-tree/</code> and then boots an OS
in a namespace container in it.</p></div></div><br class="example-break"><div class="example"><a name="idm140120373466064"></a><p class="title"><b>Example 5. Boot into an ephemeral "<code class="literal">btrfs</code>" snapshot of the host system</b></p><div class="example-contents"><pre class="programlisting"># systemd-nspawn -D / -xb</pre><p>This runs a copy of the host system in a
"<code class="literal">btrfs</code>" snapshot which is removed immediately
when the container exits. All file system changes made during
runtime will be lost on shutdown, hence.</p></div></div><br class="example-break"><div class="example"><a name="idm140120373462864"></a><p class="title"><b>Example 6. Run a container with SELinux sandbox security contexts</b></p><div class="example-contents"><pre class="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</pre></div></div><br class="example-break"></div><div class="refsect1"><a name="idm140120373461120"></a><h2 id="Exit status">Exit status<a class="headerlink" title="Permalink to this headline" href="#Exit%20status"></a></h2><p>The exit code of the program executed in the container is
returned.</p></div><div class="refsect1"><a name="idm140120373459888"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also"></a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
<a href="http://man7.org/linux/man-pages/man1/chroot.1.html"><span class="citerefentry"><span class="refentrytitle">chroot</span>(1)</span></a>,
<a href="https://www.mankier.com/8/dnf"><span class="citerefentry"><span class="refentrytitle">dnf</span>(8)</span></a>,
<a href="http://linux.die.net/man/8/yum"><span class="citerefentry"><span class="refentrytitle">yum</span>(8)</span></a>,
<a href="http://linux.die.net/man/8/debootstrap"><span class="citerefentry"><span class="refentrytitle">debootstrap</span>(8)</span></a>,
<a href="https://www.archlinux.org/pacman/pacman.8.html"><span class="citerefentry"><span class="refentrytitle">pacman</span>(8)</span></a>,
<a href="systemd.slice.html"><span class="citerefentry"><span class="refentrytitle">systemd.slice</span>(5)</span></a>,
<a href="machinectl.html"><span class="citerefentry"><span class="refentrytitle">machinectl</span>(1)</span></a>,
<a href="btrfs.html"><span class="citerefentry"><span class="refentrytitle">btrfs</span>(8)</span></a>
</p></div></div></body></html>
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