path: root/man/systemd.service.xml

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<refentry id="systemd.service">
        <refentryinfo>
                <title>systemd.service</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.service</refentrytitle>
                <manvolnum>5</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>systemd.service</refname>
                <refpurpose>systemd service configuration files</refpurpose>
        </refnamediv>

        <refsynopsisdiv>
                <para><filename>systemd.service</filename></para>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para>A configuration file ending in .service encodes
                information about a process controlled and supervised
                by systemd.</para>

                <para>This man page lists the configuration options
                specific to this unit type. See
                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                for the common options of all unit configuration
                files.</para>
        </refsect1>

        <refsect1>
                <title>Options</title>

                <variablelist>
                        <varlistentry>
                                <term><varname>Type=</varname></term>
                                <listitem>
                                        <para>One of
                                        <literal>forking</literal>,
                                        <literal>simple</literal>,
                                        <literal>finish</literal>,
                                        <literal>dbus</literal>.</para>

                                        <para>If set to
                                        <literal>forking</literal>
                                        (the default) it is expected
                                        that the process configured
                                        with
                                        <varname>ExecStart=</varname>
                                        will start up and call
                                        <function>fork()</function>. The
                                        parent process is expected to
                                        finish when start-up is
                                        complete and all communication
                                        channels set up. The child
                                        continues to run as the main
                                        daemon process. This is the
                                        behaviour of traditional UNIX
                                        daemons. If this setting is
                                        used, it is recommended to also
                                        use the
                                        <varname>PIDFile=</varname>
                                        option, so that systemd can
                                        identify the main process of
                                        the daemon. systemd will proceed
                                        starting follow-up units as soon
                                        as the parent process exits.</para>

                                        <para>If set to
                                        <literal>simple</literal> (the
                                        recommended value) it is
                                        expected that the process
                                        configured with
                                        <varname>ExecStart=</varname>
                                        is the main process of the
                                        daemon. In this mode,
                                        communication channels must be
                                        available before the daemon is
                                        started up (sockets set up by systemd),
                                        as systemd will immediately proceed
                                        starting follow-up units.</para>

                                        <para>Behaviour of
                                        <literal>finish</literal> is
                                        similar to
                                        <literal>simple</literal>,
                                        however it is expected that
                                        the process has to exit before
                                        systemd starts follow-up
                                        units. <varname>ValidNoProcess=</varname>
                                        is particularly useful for
                                        this type of service.</para>

                                        <para>Behaviour of
                                        <literal>dbus</literal> is
                                        similar to
                                        <literal>simple</literal>,
                                        however it is expected that
                                        the daemon acquires a name on
                                        the D-Bus bus, as configured
                                        by
                                        <varname>BusName=</varname>. Systemd will
                                        proceed starting follow-up
                                        units after the D-Bus bus name has been
                                        acquired.</para>
                                </listitem>
                        </varlistentry>
                        <varlistentry>
                                <term><varname>ValidNoProcess=</varname></term>
                                <listitem>
                                        <para>Takes a boolean value
                                        that specifies whether the service
                                        shall be considered active
                                        even when all its processes
                                        exited. Defaults to <literal>no</literal>.</para>
                                </listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><varname>PIDFile=</varname></term>
                                <listitem>
                                        <para>Takes an absolute file
                                        name pointing to the PID file
                                        of this daemon. Use of this
                                        option is recommended for
                                        services where
                                        <varname>Type=</varname> is
                                        set to
                                        <literal>forking</literal>.</para>
                                </listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><varname>BusName=</varname></term>
                                <listitem>
                                        <para>Takes a D-Bus bus name,
                                        where this service is reachable
                                        as. This option is mandatory
                                        for services where
                                        <varname>Type=</varname> is
                                        set to
                                        <literal>dbus</literal>, but
                                        its use is otherwise
                                        recommended as well if the
                                        process takes a name on the
                                        D-Bus bus.</para>
                                </listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><varname>ExecStart=</varname></term>
                                <listitem>
                                        <para>Takes a command line
                                        that is executed when this
                                        service shall be started
                                        up. The first word of the
                                        command line must be an
                                        absolute file name. It is
                                        mandatory to set this option
                                        for all services.</para>
                                </listitem>
                        </varlistentry>

                </variablelist>
        </refsect1>

        <refsect1>
                  <title>See Also</title>
                  <para>
                          <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
                          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                  </para>
        </refsect1>

</refentry>