Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refsynopsisdiv>
<cmdsynopsis>
- <command>systemd-nspawn <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt">COMMAND</arg> <arg choice="opt" rep="repeat">ARGS</arg></command>
+ <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>
container.</para>
<para>Use a tool like
- <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry> or <citerefentry><refentrytitle>mock</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>yum</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
- hierarchy for <command>systemd-nspawn</command> containers.</para>
+ hierarchy for <command>systemd-nspawn</command>
+ containers.</para>
<para>Note that <command>systemd-nspawn</command> will
mount file systems private to the container to
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.</para>
+ underlying file system. It is however possible to
+ enter an existing container, see
+ <link linkend='example-nsenter'>Example 4</link> below.
+ </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
+ existance 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>Incompatibility with Auditing</title>
+
+ <para>Note that the kernel auditing subsystem is
+ currently broken when used together with
+ containers. We hence recommend turning it off entirely
+ by booting with <literal>audit=0</literal> on the
+ kernel command line, or by turning it off at kernel
+ build time. If auditing is enabled in the kernel
+ operating systems booted in an nspawn container might
+ refuse log-in attempts.</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>
- <term><option>--help</option></term>
<term><option>-h</option></term>
+ <term><option>--help</option></term>
<listitem><para>Prints a short help
text and exits.</para></listitem>
</varlistentry>
<varlistentry>
- <term><option>--directory=</option></term>
+ <term><option>--version</option></term>
+
+ <listitem><para>Prints a version string
+ and exits.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><option>-D</option></term>
+ <term><option>--directory=</option></term>
<listitem><para>Directory to use as
file system root for the namespace
</varlistentry>
<varlistentry>
- <term><option>--user=</option></term>
+ <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.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><option>-u</option></term>
+ <term><option>--user=</option></term>
<listitem><para>Run the command
under specified user, create home
</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>--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>-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>
loopback device.</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>--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><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.</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>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. 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 doesn't 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=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>
</variablelist>
</refsect1>
<refsect1>
<title>Example 1</title>
- <programlisting># debootstrap --arch=amd64 unstable debian-tree/
-# systemd-nspawn -D debian-tree/</programlisting>
+ <programlisting># yum -y --releasever=19 --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>
+ </refsect1>
+
+ <refsect1>
+ <title>Example 2</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
+ <filename>~/debian-tree/</filename> and then spawns a
shell in a namespace container in it.</para>
-
</refsect1>
<refsect1>
- <title>Example 2</title>
+ <title>Example 3</title>
- <programlisting># mock --init
-# systemd-nspawn -D /var/lib/mock/fedora-rawhide-x86_64/root/ /sbin/init systemd.log_level=debug</programlisting>
+ <programlisting># pacstrap -c -d ~/arch-tree/ base
+# systemd-nspawn -bD ~/arch-tree/</programlisting>
- <para>This installs a minimal Fedora distribution into
- a subdirectory of <filename>/var/lib/mock/</filename>
- and then boots an OS in a namespace container in it,
- with systemd as init system, configured for debug
- logging.</para>
+ <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>
+ </refsect1>
+
+ <refsect1 id='example-nsenter'>
+ <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># nsenter -m -u -i -n -p -t $PID</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>
</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>mock</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>pacman</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff