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nspawn: add new --setenv= switch to set an environment variable for the container...
[elogind.git] / man / systemd-nspawn.xml
index 71ce0aca438e1c581254156bd23bf74f687e1b1d..bec233c1ca9eb9c056df7dc72a385483b3de8a16 100644 (file)
 
         <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>
 
                 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>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
                 or
-                <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                <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>
                 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. 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>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
-                                container. If omitted the current
+                                container. If omitted, the current
                                 directory will be
                                 used.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
-                                <term><option>--boot</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.</para></listitem>
+                                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>--user=</option></term>
                                 <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>--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>--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>--controllers=</option></term>
-                                <term><option>-C</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
-                                the following capabilities will be
-                                granted in any way: CAP_CHOWN,
+                                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_SETUID, CAP_SYS_ADMIN,
                                 CAP_SYS_CHROOT, CAP_SYS_NICE,
                                 CAP_SYS_PTRACE, CAP_SYS_TTY_CONFIG,
-                                CAP_SYS_RESOURCE, CAP_SYS_BOOT.</para></listitem>
+                                CAP_SYS_RESOURCE, CAP_SYS_BOOT,
+                                CAP_AUDIT_WRITE,
+                                CAP_AUDIT_CONTROL.</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
                                 not linked. If <literal>host</literal>,
                                 the journal files are stored on the
                                 host file system (beneath
-                                <filename>/var/log/journal/&lt;machine-id&gt;</filename>)
+                                <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/&lt;machine-id&gt;</filename>)
+                                <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),
                                 <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>
+
                 </variablelist>
 
         </refsect1>
         <refsect1>
                 <title>Example 1</title>
 
-                <programlisting># yum --releasever=17 --nogpgcheck --installroot ~/fedora-tree/ install yum passwd vim-minimal rootfiles systemd
-# systemd-nspawn -D ~/fedora-tree /usr/lib/systemd/systemd</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>~/fedora-tree/</filename>
-                and then boots an OS in a namespace container in it,
-                with systemd as init system.</para>
+                the directory <filename noindex='true'>/srv/mycontainer/</filename> and
+                then boots an OS in a namespace container in
+                it.</para>
         </refsect1>
 
         <refsect1>
                 distribution into the directory
                 <filename>~/debian-tree/</filename> and then spawns a
                 shell in a namespace container in it.</para>
+        </refsect1>
 
+        <refsect1>
+                <title>Example 3</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>
         </refsect1>
 
+        <refsect1>
+                <title>Example 4</title>
+
+                <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>Exit status</title>
 
                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                         <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                         <citerefentry><refentrytitle>yum</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
-                        <citerefentry><refentrytitle>debootstrap</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                        <citerefentry><refentrytitle>debootstrap</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>