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
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>
<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. If this option is used, arguments
- specified on the command line are used
- as arguments for the init binary.
+ 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>
host, and is used to initialize the
container's hostname (which the
container can choose to override,
- however). If not specified the last
+ however). If not specified, the last
component of the root directory of the
container is used.</para></listitem>
</varlistentry>
</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>
loopback device.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--network-interface=</option></term>
+
+ <listitem><para>Assign the specified
+ network interface to the
+ container. This will move 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.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>--read-only</option></term>
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
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>
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 -m -u -i -n -p -t $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>systemd.slice</refentrytitle><manvolnum>5</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