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| Copyright 2015 Lennart Poettering |
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| |
| <refentry id="systemd.nspawn"> |
| |
| <refentryinfo> |
| <title>systemd.nspawn</title> |
| <productname>systemd</productname> |
| |
| <authorgroup> |
| <author> |
| <contrib>Developer</contrib> |
| <firstname>Lennart</firstname> |
| <surname>Poettering</surname> |
| <email>lennart@poettering.net</email> |
| </author> |
| </authorgroup> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>systemd.nspawn</refentrytitle> |
| <manvolnum>5</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>systemd.nspawn</refname> |
| <refpurpose>Container settings</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <para><filename>/etc/systemd/nspawn/<replaceable>machine</replaceable>.nspawn</filename></para> |
| <para><filename>/run/systemd/nspawn/<replaceable>machine</replaceable>.nspawn</filename></para> |
| <para><filename>/var/lib/machines/<replaceable>machine</replaceable>.nspawn</filename></para> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para>An nspawn container settings file (suffix |
| <filename>.nspawn</filename>) encodes additional runtime |
| information about a local container, and is searched, read and |
| used by |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| when starting a container. Files of this type are named after the |
| containers they define settings for. They are optional, and only |
| required for containers whose execution environment shall differ |
| from the defaults. Files of this type mostly contain settings that |
| may also be set on the <command>systemd-nspawn</command> command |
| line, and make it easier to persistently attach specific settings |
| to specific containers. The syntax of these files is inspired by |
| <filename>.desktop</filename> files following the <ulink |
| url="http://standards.freedesktop.org/desktop-entry-spec/latest/">XDG |
| Desktop Entry Specification</ulink>, which in turn are inspired by |
| Microsoft Windows <filename>.ini</filename> files.</para> |
| |
| <para>Boolean arguments used in these settings files can be |
| written in various formats. For positive settings, the strings |
| <option>1</option>, <option>yes</option>, <option>true</option> |
| and <option>on</option> are equivalent. For negative settings, the |
| strings <option>0</option>, <option>no</option>, |
| <option>false</option> and <option>off</option> are |
| equivalent.</para> |
| |
| <para>Empty lines and lines starting with # or ; are |
| ignored. This may be used for commenting. Lines ending |
| in a backslash are concatenated with the following |
| line while reading and the backslash is replaced by a |
| space character. This may be used to wrap long lines.</para> |
| |
| </refsect1> |
| |
| <refsect1> |
| <title><filename>.nspawn</filename> File Discovery</title> |
| |
| <para>Files are searched by appending the |
| <filename>.nspawn</filename> suffix to the machine name of the |
| container, as specified with the <option>--machine=</option> |
| switch of <command>systemd-nspawn</command>, or derived from the |
| directory or image file name. This file is first searched in |
| <filename>/etc/systemd/nspawn/</filename> and |
| <filename>/run/systemd/nspawn/</filename>. If found in these |
| directories, its settings are read and all of them take full effect |
| (but are possibly overridden by corresponding command line |
| arguments). If not found, the file will then be searched next to |
| the image file or in the immediate parent of the root directory of |
| the container. If the file is found there, only a subset of the |
| settings will take effect however. All settings that possibly |
| elevate privileges or grant additional access to resources of the |
| host (such as files or directories) are ignored. To which options |
| this applies is documented below.</para> |
| |
| <para>Persistent settings files created and maintained by the |
| administrator (and thus trusted) should be placed in |
| <filename>/etc/systemd/nspawn/</filename>, while automatically |
| downloaded (and thus potentially untrusted) settings files are |
| placed in <filename>/var/lib/machines/</filename> instead (next to |
| the container images), where their security impact is limited. In |
| order to add privileged settings to <filename>.nspawn</filename> |
| files acquired from the image vendor, it is recommended to copy the |
| settings files into <filename>/etc/systemd/nspawn/</filename> and |
| edit them there, so that the privileged options become |
| available. The precise algorithm for how the files are searched and |
| interpreted may be configured with |
| <command>systemd-nspawn</command>'s <option>--settings=</option> |
| switch, see |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| for details.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>[Exec] Section Options</title> |
| |
| <para>Settings files may include an <literal>[Exec]</literal> |
| section, which carries various execution parameters:</para> |
| |
| <variablelist> |
| |
| <varlistentry> |
| <term><varname>Boot=</varname></term> |
| |
| <listitem><para>Takes a boolean argument, which defaults to off. If enabled, <command>systemd-nspawn</command> |
| will automatically search for an <filename>init</filename> executable and invoke it. In this case, the |
| specified parameters using <varname>Parameters=</varname> are passed as additional arguments to the |
| <filename>init</filename> process. This setting corresponds to the <option>--boot</option> switch on the |
| <command>systemd-nspawn</command> command line. This option may not be combined with |
| <varname>ProcessTwo=yes</varname>. This option is the default if the |
| <filename>systemd-nspawn@.service</filename> template unit file is used.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>ProcessTwo=</varname></term> |
| |
| <listitem><para>Takes a boolean argument, which defaults to off. If enabled, the specified program is run as |
| PID 2. A stub init process is run as PID 1. This setting corresponds to the <option>--as-pid2</option> switch |
| on the <command>systemd-nspawn</command> command line. This option may not be combined with |
| <varname>Boot=yes</varname>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Parameters=</varname></term> |
| |
| <listitem><para>Takes a space-separated list of |
| arguments. This is either a command line, beginning with the |
| binary name to execute, or – if <varname>Boot=</varname> is |
| enabled – the list of arguments to pass to the init |
| process. This setting corresponds to the command line |
| parameters passed on the <command>systemd-nspawn</command> |
| command line.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Environment=</varname></term> |
| |
| <listitem><para>Takes an environment variable assignment |
| consisting of key and value, separated by |
| <literal>=</literal>. Sets an environment variable for the |
| main process invoked in the container. This setting may be |
| used multiple times to set multiple environment variables. It |
| corresponds to the <option>--setenv=</option> command line |
| switch.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>User=</varname></term> |
| |
| <listitem><para>Takes a UNIX user name. Specifies the user |
| name to invoke the main process of the container as. This user |
| must be known in the container's user database. This |
| corresponds to the <option>--user=</option> command line |
| switch.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>WorkingDirectory=</varname></term> |
| |
| <listitem><para>Selects the working directory for the process invoked in the container. Expects an absolute |
| path in the container's file system namespace. This corresponds to the <option>--chdir=</option> command line |
| switch.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Capability=</varname></term> |
| <term><varname>DropCapability=</varname></term> |
| |
| <listitem><para>Takes a space-separated list of Linux process |
| capabilities (see |
| <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| for details). The <varname>Capability=</varname> setting |
| specifies additional capabilities to pass on top of the |
| default set of capabilities. The |
| <varname>DropCapability=</varname> setting specifies |
| capabilities to drop from the default set. These settings |
| correspond to the <option>--capability=</option> and |
| <option>--drop-capability=</option> command line |
| switches. Note that <varname>Capability=</varname> is a |
| privileged setting, and only takes effect in |
| <filename>.nspawn</filename> files in |
| <filename>/etc/systemd/nspawn/</filename> and |
| <filename>/run/system/nspawn/</filename> (see above). On the |
| other hand, <varname>DropCapability=</varname> takes effect in |
| all cases.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>KillSignal=</varname></term> |
| |
| <listitem><para>Specify the process signal to send to the |
| container's PID 1 when nspawn itself receives SIGTERM, in |
| order to trigger an orderly shutdown of the container. |
| Defaults to SIGRTMIN+3 if <option>Boot=</option> is used |
| (on systemd-compatible init systems SIGRTMIN+3 triggers an |
| orderly shutdown). For a list of valid signals, see |
| <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Personality=</varname></term> |
| |
| <listitem><para>Configures the kernel personality for the |
| container. This is equivalent to the |
| <option>--personality=</option> switch.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>MachineID=</varname></term> |
| |
| <listitem><para>Configures the 128-bit machine ID (UUID) to pass to |
| the container. This is equivalent to the |
| <option>--uuid=</option> command line switch. This option is |
| privileged (see above). </para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>PrivateUsers=</varname></term> |
| |
| <listitem><para>Configures support for usernamespacing. This is equivalent to the |
| <option>--private-users=</option> command line switch, and takes the same options. This option is privileged |
| (see above). This option is the default if the <filename>systemd-nspawn@.service</filename> template unit file |
| is used.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>NotifyReady=</varname></term> |
| |
| <listitem><para>Configures support for notifications from the container's init process. |
| This is equivalent to use <option>--notify-ready=</option> command line switch, |
| and takes the same options. See <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| for details about the specific options supported.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>[Files] Section Options</title> |
| |
| <para>Settings files may include a <literal>[Files]</literal> |
| section, which carries various parameters configuring the file |
| system of the container:</para> |
| |
| <variablelist> |
| |
| <varlistentry> |
| <term><varname>ReadOnly=</varname></term> |
| |
| <listitem><para>Takes a boolean argument, which defaults to off. If |
| specified, the container will be run with a read-only file |
| system. This setting corresponds to the |
| <option>--read-only</option> command line |
| switch.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Volatile=</varname></term> |
| |
| <listitem><para>Takes a boolean argument, or the special value |
| <literal>state</literal>. This configures whether to run the |
| container with volatile state and/or configuration. This |
| option is equivalent to <option>--volatile=</option>, see |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| for details about the specific options |
| supported.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Bind=</varname></term> |
| <term><varname>BindReadOnly=</varname></term> |
| |
| <listitem><para>Adds a bind mount from the host into the |
| container. Takes a single path, a pair of two paths separated |
| by a colon, or a triplet of two paths plus an option string |
| separated by colons. This option may be used multiple times to |
| configure multiple bind mounts. This option is equivalent to |
| the command line switches <option>--bind=</option> and |
| <option>--bind-ro=</option>, see |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| for details about the specific options supported. This setting |
| is privileged (see above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>TemporaryFileSystem=</varname></term> |
| |
| <listitem><para>Adds a <literal>tmpfs</literal> mount to the |
| container. Takes a path or a pair of path and option string, |
| separated by a colon. This option may be used multiple times to |
| configure multiple <literal>tmpfs</literal> mounts. This |
| option is equivalent to the command line switch |
| <option>--tmpfs=</option>, see |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| for details about the specific options supported. This setting |
| is privileged (see above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>PrivateUsersChown=</varname></term> |
| |
| <listitem><para>Configures whether the ownership of the files and directories in the container tree shall be |
| adjusted to the UID/GID range used, if necessary and user namespacing is enabled. This is equivalent to the |
| <option>--private-users-chown</option> command line switch. This option is privileged (see |
| above). </para></listitem> |
| </varlistentry> |
| |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>[Network] Section Options</title> |
| |
| <para>Settings files may include a <literal>[Network]</literal> |
| section, which carries various parameters configuring the network |
| connectivity of the container:</para> |
| |
| <variablelist> |
| |
| <varlistentry> |
| <term><varname>Private=</varname></term> |
| |
| <listitem><para>Takes a boolean argument, which defaults to off. If |
| enabled, the container will run in its own network namespace |
| and not share network interfaces and configuration with the |
| host. This setting corresponds to the |
| <option>--private-network</option> command line |
| switch.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>VirtualEthernet=</varname></term> |
| |
| <listitem><para>Takes a boolean argument. Configures whether to create a virtual Ethernet connection |
| (<literal>veth</literal>) between host and the container. This setting implies |
| <varname>Private=yes</varname>. This setting corresponds to the <option>--network-veth</option> command line |
| switch. This option is privileged (see above). This option is the default if the |
| <filename>systemd-nspawn@.service</filename> template unit file is used.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>VirtualEthernetExtra=</varname></term> |
| |
| <listitem><para>Takes a colon-separated pair of interface |
| names. Configures an additional virtual Ethernet connection |
| (<literal>veth</literal>) between host and the container. The |
| first specified name is the interface name on the host, the |
| second the interface name in the container. The latter may be |
| omitted in which case it is set to the same name as the host |
| side interface. This setting implies |
| <varname>Private=yes</varname>. This setting corresponds to |
| the <option>--network-veth-extra=</option> command line |
| switch, and maybe be used multiple times. It is independent of |
| <varname>VirtualEthernet=</varname>. This option is privileged |
| (see above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Interface=</varname></term> |
| |
| <listitem><para>Takes a space-separated list of interfaces to |
| add to the container. This option corresponds to the |
| <option>--network-interface=</option> command line switch and |
| implies <varname>Private=yes</varname>. This option is |
| privileged (see above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>MACVLAN=</varname></term> |
| <term><varname>IPVLAN=</varname></term> |
| |
| <listitem><para>Takes a space-separated list of interfaces to |
| add MACLVAN or IPVLAN interfaces to, which are then added to |
| the container. These options correspond to the |
| <option>--network-macvlan=</option> and |
| <option>--network-ipvlan=</option> command line switches and |
| imply <varname>Private=yes</varname>. These options are |
| privileged (see above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Bridge=</varname></term> |
| |
| <listitem><para>Takes an interface name. This setting implies |
| <varname>VirtualEthernet=yes</varname> and |
| <varname>Private=yes</varname> and has the effect that the |
| host side of the created virtual Ethernet link is connected to |
| the specified bridge interface. This option corresponds to the |
| <option>--network-bridge=</option> command line switch. This |
| option is privileged (see above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Zone=</varname></term> |
| |
| <listitem><para>Takes a network zone name. This setting implies <varname>VirtualEthernet=yes</varname> and |
| <varname>Private=yes</varname> and has the effect that the host side of the created virtual Ethernet link is |
| connected to an automatically managed bridge interface named after the passed argument, prefixed with |
| <literal>vz-</literal>. This option corresponds to the <option>--network-zone=</option> command line |
| switch. This option is privileged (see above).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Port=</varname></term> |
| |
| <listitem><para>Exposes a TCP or UDP port of the container on |
| the host. This option corresponds to the |
| <option>--port=</option> command line switch, see |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| for the precise syntax of the argument this option takes. This |
| option is privileged (see above).</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |