<refsect1>
<title>Description</title>
- <para>A configuration file ending in .service encodes
- information about a process controlled and supervised
- by systemd.</para>
+ <para>A unit configuration file whose name ends in
+ <filename>.service</filename> 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>
+ files. The common configuration items are configured
+ in the generic <literal>[Unit]</literal> and
+ <literal>[Install]</literal> sections. The service
+ specific configuration options are configured in the
+ <literal>[Service]</literal> section.</para>
+
+ <para>Additional options are listed in
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ which define the execution environment the commands
+ are executed in.</para>
+
+ <para>Unless <varname>DefaultDependencies=</varname>
+ is set to <option>false</option>, service units will
+ implicitly have dependencies of type
+ <varname>Requires=</varname> and
+ <varname>After=</varname> on
+ <filename>basic.target</filename> as well as
+ dependencies of type <varname>Conflicts=</varname> and
+ <varname>Before=</varname> on
+ <filename>shutdown.target</filename>. These ensure
+ that normal service units pull in basic system
+ initialization, and are terminated cleanly prior to
+ system shutdown. Only services involved with early
+ boot or late system shutdown should disable this
+ option.</para>
+
+ <para>If a service is requested under a certain name
+ but no unit configuration file is found, systemd looks
+ for a SysV init script by the same name (with the
+ <filename>.service</filename> suffix removed) and
+ dynamically creates a service unit from that
+ script. This is useful for compatibility with
+ SysV.</para>
</refsect1>
<refsect1>
<title>Options</title>
+ <para>Service files must include a
+ <literal>[Service]</literal> section, which carries
+ information about the service and the process it
+ supervises. A number of options that may be used in
+ this section are shared with other unit types. These
+ options are documented in
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
+ options specific to the <literal>[Service]</literal>
+ section of service units are the following:</para>
+
<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 start
- follow-up units as soon as the
- parent process exited.</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, as systemd will
- immediately start 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>. Follow-up
- units will be started after
- the name has been
- acquired.</para>
+
+ <listitem><para>Configures the process
+ start-up type for this service
+ unit. One of <option>simple</option>,
+ <option>forking</option>,
+ <option>finish</option>,
+ <option>dbus</option>,
+ <option>notify</option>.</para>
+
+ <para>If set to
+ <option>simple</option> (the default
+ value) it is expected that the process
+ configured with
+ <varname>ExecStart=</varname> is the
+ main process of the service. In this
+ mode, communication channels must be
+ installed before the daemon is started
+ up (e.g. sockets set up by systemd,
+ via socket activation), as systemd
+ will immediately proceed starting
+ follow-up units.</para>
+
+ <para>If set to
+ <option>forking</option> 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>Behaviour of
+ <option>finish</option> is similar
+ to <option>simple</option>, 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
+ <option>dbus</option> is similar to
+ <option>simple</option>, 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. Service units with this
+ option configured implicitly have
+ dependencies on the
+ <filename>dbus.target</filename>
+ unit.</para>
+
+ <para>Behaviour of
+ <option>notify</option> is similar to
+ <option>simple</option>, however it is
+ expected that the daemon sends a
+ notification message via
+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ or an equivalent call when it finished
+ starting up. systemd will proceed
+ starting follow-up units after this
+ notification message has been sent. If
+ this option is used
+ <varname>NotifyAccess=</varname> (see
+ below) must be set to open access to
+ the notification socket provided by
+ systemd. If
+ <varname>NotifyAccess=</varname> is not
+ set, it will be implicitly set to
+ <option>main</option>.</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><para>Takes a boolean value
+ that specifies whether the service
+ shall be considered active even when
+ all its processes exited. Defaults to
+ <option>no</option>.</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><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
+ <option>forking</option>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>BusName=</varname></term>
- <listitem>
- <para>Takes a D-Bus bus name
- that 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><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
+ <option>dbus</option>, 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>
+ <listitem><para>Takes a command line
+ that is executed when this service
+ shall be started up. The first token
+ of the command line must be an
+ absolute file name, then followed by
+ arguments for the process. It is
+ mandatory to set this option for all
+ services. This option may not be
+ specified more than once. Optionally,
+ if the absolute file name is prefixed
+ with <literal>@</literal>, the second
+ token will be passed as
+ <literal>argv[0]</literal> to the
+ executed process, followed by the
+ further arguments specified. Unless
+ <varname>Type=forking</varname> is set,
+ the process started via this command
+ line will be considered the main
+ process of the
+ daemon.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ExecStartPre=</varname></term>
+ <term><varname>ExecStartPost=</varname></term>
+ <listitem><para>Additional commands
+ that are executed before (resp. after)
+ the command in
+ <varname>ExecStart=</varname>. If
+ specified more than once, all commands
+ are executed one after the other,
+ serially. Use of these settings is
+ optional.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ExecReload=</varname></term>
+ <listitem><para>Commands to execute to
+ trigger a configuration reload in the
+ service. If used more than once, all
+ commands are executed one after the
+ other, serially. Use of this setting is optional.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ExecStop=</varname></term>
+ <listitem><para>Commands to execute to
+ stop the service started via
+ <varname>ExecStart=</varname>. If used
+ more than once, all commands are
+ executed one after the other,
+ serially. Use of this setting is
+ optional. All processes remaining for
+ a service after the commands
+ configured in this option are run are
+ terminated according to the
+ <varname>KillMode=</varname> setting
+ (see below). If this option is not
+ specified the process is terminated
+ right-away when service stop is
+ requested.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ExecStopPost=</varname></term>
+ <listitem><para>Additional commands
+ that are executed after the service
+ was stopped using the commands
+ configured in
+ <varname>ExecStop=</varname>. If
+ specified more than once, all commands
+ are executed one after the other,
+ serially. Use of these settings is
+ optional.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RestartSec=</varname></term>
+ <listitem><para>Configures the time to
+ sleep before restarting a service (as
+ configured with
+ <varname>Restart=</varname>). Takes a
+ unit-less value in seconds, or a time
+ span value such as "5min
+ 20s". Defaults to
+ 100ms.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>TimeoutSec=</varname></term>
+ <listitem><para>Configures the time to
+ wait for start-up and stop. If a
+ daemon service does not signal
+ start-up completion within the
+ configured time the service will be
+ considered failed and be shut down
+ again. If a service is asked to stop
+ but does not terminate in the
+ specified time it will be terminated
+ forcibly via SIGTERM, and after
+ another delay of this time with
+ SIGKILL. (See
+ <varname>KillMode=</varname>
+ below.) Takes a unit-less value in seconds, or a
+ time span value such as "5min
+ 20s". Pass 0 to disable the timeout
+ logic. Defaults to
+ 60s.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>Restart=</varname></term>
+ <listitem><para>Configures whether the
+ main service process shall be restarted when
+ it exists. Takes one of
+ <option>once</option>,
+ <option>restart-on-success</option> or
+ <option>restart-always</option>. If
+ set to <option>once</option> (the
+ default) the service will not be
+ restarted when it exits. If set to
+ <option>restart-on-success</option> it
+ will be restarted only when it exited
+ cleanly, i.e. terminated with an exit
+ code of 0. If set to
+ <option>restart-always</option> the
+ service will be restarted regardless
+ whether it exited cleanly or not, or
+ got terminated abnormally by a
+ signal.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>PermissionsStartOnly=</varname></term>
+ <listitem><para>Takes a boolean
+ argument. If true, the permission
+ related execution options as
+ configured with
+ <varname>User=</varname> and similar
+ options (see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for more information) are only applied
+ to the process started with
+ <varname>ExecStart=</varname>, and not
+ to the various other
+ <varname>ExecStartPre=</varname>,
+ <varname>ExecStartPost=</varname>,
+ <varname>ExecReload=</varname>,
+ <varname>ExecStop=</varname>,
+ <varname>ExecStopPost=</varname>
+ commands. If false, the setting is
+ applied to all configured commands the
+ same way. Defaults to
+ false.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>RootDirectoryStartOnly=</varname></term>
+ <listitem><para>Takes a boolean
+ argument. If true, the root directory
+ as configured with the
+ <varname>RootDirectory=</varname>
+ option (see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for more information) is only applied
+ to the process started with
+ <varname>ExecStart=</varname>, and not
+ to the various other
+ <varname>ExecStartPre=</varname>,
+ <varname>ExecStartPost=</varname>,
+ <varname>ExecReload=</varname>,
+ <varname>ExecStop=</varname>,
+ <varname>ExecStopPost=</varname>
+ commands. If false, the setting is
+ applied to all configured commands the
+ same way. Defaults to
+ false.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>SysVStartPriority=</varname></term>
+ <listitem><para>Set the SysV start
+ priority to use to order this service
+ in relation to SysV services lacking
+ LSB headers. This option is only
+ necessary to fix ordering in relation
+ to legacy SysV services, that have no
+ ordering information encoded in the
+ script headers. As such it should only
+ be used as temporary compatibility
+ option, and not be used in new unit
+ files. Almost always it is a better
+ choice to add explicit ordering
+ directives via
+ <varname>After=</varname> or
+ <varname>Before=</varname>,
+ instead. For more details see
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
+ used, pass an integer value in the
+ range 0-99.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>KillMode=</varname></term>
+ <listitem><para>Specifies how
+ processes of this service shall be
+ killed. One of
+ <option>control-group</option>,
+ <option>process-group</option>,
+ <option>process</option>,
+ <option>none</option>.</para>
+
+ <para>If set to
+ <option>control-group</option> all
+ remaining processes in the control
+ group of this service will be
+ terminated on service stop, after the
+ stop command (as configured with
+ <varname>ExecStop=</varname>) is
+ executed. If set to
+ <option>process-group</option> only
+ the members of the process group of
+ the main service process are
+ killed. If set to
+ <option>process</option> only the main
+ process itself is killed. If set to
+ <option>none</option> no process is
+ killed. In this case only the stop
+ command will be executed on service
+ stop, but no process be killed
+ otherwise. Processes remaining alive
+ after stop are left in their control
+ group and the control group continues
+ to exist after stop unless it is
+ empty. Defaults to
+ <option>control-croup</option>.</para>
+
+ <para>Processes will first be
+ terminated via SIGTERM. If then after
+ a delay (configured via the
+ <varname>TimeoutSec=</varname> option)
+ processes still remain, the
+ termination request is repeated with
+ the SIGKILL signal. See
+ <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ for more
+ information.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>NonBlocking=</varname></term>
+ <listitem><para>Set O_NONBLOCK flag
+ for all file descriptors passed via
+ socket-based activation. If true, all
+ file descriptors >= 3 (i.e. all except
+ STDIN/STDOUT/STDERR) will have
+ the O_NONBLOCK flag set and hence are in
+ non-blocking mode. This option is only
+ useful in conjunction with a socket
+ unit, as described in
+ <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
+ to false.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>NotifyAccess=</varname></term>
+ <listitem><para>Controls access to the
+ service status notification socket, as
+ accessible via the
+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ call. Takes one of
+ <option>none</option> (the default),
+ <option>main</option> or
+ <option>all</option>. If
+ <option>none</option> no daemon status
+ updates are accepted by the service
+ processes, all status update messages
+ are ignored. If <option>main</option>
+ only service updates sent from the
+ main process of the service are
+ accepted. If <option>all</option> all
+ services updates from all members of
+ the service's control group are
+ accepted. This option must be set to
+ open access to the notification socket
+ when using
+ <varname>Type=notify</varname> (see above).</para></listitem>
</varlistentry>
</variablelist>
<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>
+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff