<cmdsynopsis>
<command>systemd-nspawn</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
- <arg choice="opt">COMMAND</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>
involved with boot and systems management.</para>
<para>In contrast to
- <citerefentry><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>
+ <citerefentry><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><refentrytitle>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
or
<citerefentry><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>
to set up an OS directory tree suitable as file system
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. It is however possible to
- enter an existing container, see
- <link linkend='example-nsenter'>Example 4</link> below.
- </para>
+ 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>/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 no arguments are passed the container is set
- up and a shell started in it, otherwise the passed
- command and arguments are executed in it. The
- following options are understood:</para>
+ <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>
<listitem><para>Directory to use as
file system root for the namespace
- container. If omitted the current
+ container. If omitted, the current
directory will be
used.</para></listitem>
</varlistentry>
<listitem><para>Automatically search
for an init binary and invoke it
instead of a shell or a user supplied
- program.</para></listitem>
+ 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>
</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 on the
+ host, 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 of the
+ container is used.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>--slice=</option></term>
+
+ <listitem><para>Make the container
+ part of the specified slice, instead
+ of the
+ <filename>machine.slice</filename>.</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>--uuid=</option></term>
- <listitem><para>Set the specified uuid
+ <listitem><para>Set the specified UUID
for the container. The init system
will initialize
<filename>/etc/machine-id</filename>
</para></listitem>
</varlistentry>
- <varlistentry>
- <term><option>-C</option></term>
- <term><option>--controllers=</option></term>
-
- <listitem><para>Makes the container appear in
- other hierarchies than the name=systemd:/ one.
- Takes a comma-separated list of controllers.
- </para></listitem>
- </varlistentry>
-
<varlistentry>
<term><option>--private-network</option></term>
<term><option>--read-only</option></term>
<listitem><para>Mount the root file
- system read only for the
+ system read-only for the
container.</para></listitem>
</varlistentry>
<listitem><para>List one or more
additional capabilities to grant the
- container. Takes a comma separated
+ container. Takes a comma-separated
list of capability names, see
<citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for more information. Note that the
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.</para></listitem>
+ CAP_AUDIT_WRITE, CAP_AUDIT_CONTROL. 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>
<listitem><para>Control whether the
container's journal shall be made
- visible to the host system. If enabled
+ visible to the host system. If enabled,
allows viewing the container's journal
files from the host (but not vice
versa). Takes one of
<filename>/var/log/journal</filename>
exists, it will be bind mounted
into the container. If the
- subdirectory doesn't exist, no
+ subdirectory does not exist, no
linking is performed. Effectively,
booting a container once with
<literal>guest</literal> or
<listitem><para>Equivalent to
<option>--link-journal=guest</option>.</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
+ mount.</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>-q</option></term>
+ <term><option>--quiet</option></term>
+
+ <listitem><para>Turns off any status
+ output by the tool itself. When this
+ switch is used, then the only output
+ by nspawn will be the console output
+ of the container OS itself.</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><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 in
+ <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 an 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>
+
</variablelist>
</refsect1>
# systemd-nspawn -bD /srv/mycontainer</programlisting>
<para>This installs a minimal Fedora distribution into
- the directory <filename>/srv/mycontainer/</filename> and
+ the directory <filename noindex='true'>/srv/mycontainer/</filename> and
then boots an OS in a namespace container in
it.</para>
</refsect1>
boots an OS in a namespace container in it.</para>
</refsect1>
- <refsect1 id='example-nsenter'>
+ <refsect1>
<title>Example 4</title>
- <para>To enter the container, PID of one of the
- processes sharing the new namespaces must be used.
- <command>systemd-nspawn</command> prints the PID
- (as viewed from the outside) of the launched process,
- and it can be used to enter the container.</para>
+ <programlisting># mv ~/arch-tree /var/lib/container/arch
+# systemctl enable systemd-nspawn@arch.service
+# systemctl start systemd-nspawn@arch.service</programlisting>
+
+ <para>This makes the Arch Linux container part of the
+ <filename>multi-user.target</filename> on the host.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Example 5</title>
+
+ <programlisting># btrfs subvolume snapshot / /.tmp
+# systemd-nspawn --private-network -D /.tmp -b</programlisting>
+
+ <para>This runs a copy of the host system in a
+ btrfs snapshot.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Example 6</title>
- <programlisting># nsenter -muinpt $PID</programlisting>
+ <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>
- <para><citerefentry><refentrytitle>nsenter</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- is part of
- <ulink url="https://github.com/karelzak/util-linux">util-linux</ulink>.
- Kernel support for entering namespaces was added in
- Linux 3.8.</para>
+ <para>This runs a container with SELinux sandbox security contexts.</para>
</refsect1>
<refsect1>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>unshare</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff