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7 This file is part of systemd.
9 Copyright 2010 Lennart Poettering
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25 <refentry id="systemd.service">
27 <title>systemd.service</title>
28 <productname>systemd</productname>
32 <contrib>Developer</contrib>
33 <firstname>Lennart</firstname>
34 <surname>Poettering</surname>
35 <email>lennart@poettering.net</email>
41 <refentrytitle>systemd.service</refentrytitle>
42 <manvolnum>5</manvolnum>
46 <refname>systemd.service</refname>
47 <refpurpose>Service unit configuration</refpurpose>
51 <para><filename><replaceable>service</replaceable>.service</filename></para>
55 <title>Description</title>
57 <para>A unit configuration file whose name ends in
58 <filename>.service</filename> encodes information
59 about a process controlled and supervised by
62 <para>This man page lists the configuration options
63 specific to this unit type. See
64 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
65 for the common options of all unit configuration
66 files. The common configuration items are configured
67 in the generic <literal>[Unit]</literal> and
68 <literal>[Install]</literal> sections. The service
69 specific configuration options are configured in the
70 <literal>[Service]</literal> section.</para>
72 <para>Additional options are listed in
73 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
74 which define the execution environment the commands
75 are executed in, and in
76 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
77 which define the way the processes of the service are
79 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
80 which configure resource control settings for the
81 processes of the service.</para>
83 <para>Unless <varname>DefaultDependencies=</varname>
84 is set to <option>false</option>, service units will
85 implicitly have dependencies of type
86 <varname>Requires=</varname> and
87 <varname>After=</varname> on
88 <filename>basic.target</filename> as well as
89 dependencies of type <varname>Conflicts=</varname> and
90 <varname>Before=</varname> on
91 <filename>shutdown.target</filename>. These ensure
92 that normal service units pull in basic system
93 initialization, and are terminated cleanly prior to
94 system shutdown. Only services involved with early
95 boot or late system shutdown should disable this
98 <para>If a service is requested under a certain name
99 but no unit configuration file is found, systemd looks
100 for a SysV init script by the same name (with the
101 <filename>.service</filename> suffix removed) and
102 dynamically creates a service unit from that
103 script. This is useful for compatibility with
104 SysV. Note that this compatibility is quite
105 comprehensive but not 100%. For details about the
106 incompatibilities, see the <ulink
107 url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
108 with SysV</ulink> document.
113 <title>Options</title>
115 <para>Service files must include a
116 <literal>[Service]</literal> section, which carries
117 information about the service and the process it
118 supervises. A number of options that may be used in
119 this section are shared with other unit types. These
120 options are documented in
121 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
123 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
124 options specific to the <literal>[Service]</literal>
125 section of service units are the following:</para>
127 <variablelist class='unit-directives'>
129 <term><varname>Type=</varname></term>
131 <listitem><para>Configures the process
132 start-up type for this service
133 unit. One of <option>simple</option>,
134 <option>forking</option>,
135 <option>oneshot</option>,
136 <option>dbus</option>,
137 <option>notify</option> or
138 <option>idle</option>.</para>
141 <option>simple</option> (the default
143 <varname>Type=</varname> nor
144 <varname>BusName=</varname>, but
145 <varname>ExecStart=</varname> are
146 specified), it is expected that the
147 process configured with
148 <varname>ExecStart=</varname> is the
149 main process of the service. In this
150 mode, if the process offers
151 functionality to other processes on
152 the system, its communication channels
153 should be installed before the daemon
154 is started up (e.g. sockets set up by
155 systemd, via socket activation), as
156 systemd will immediately proceed
157 starting follow-up units.</para>
160 <option>forking</option>, it is
161 expected that the process configured
162 with <varname>ExecStart=</varname>
163 will call <function>fork()</function>
164 as part of its start-up. The parent process is
165 expected to exit when start-up is
166 complete and all communication
167 channels are set up. The child continues
168 to run as the main daemon
169 process. This is the behavior of
170 traditional UNIX daemons. If this
171 setting is used, it is recommended to
173 <varname>PIDFile=</varname> option, so
174 that systemd can identify the main
175 process of the daemon. systemd will
176 proceed with starting follow-up units
177 as soon as the parent process
181 <option>oneshot</option> is similar to
182 <option>simple</option>; however, it
183 is expected that the process has to
184 exit before systemd starts follow-up
185 units. <varname>RemainAfterExit=</varname>
186 is particularly useful for this type
187 of service. This is the implied
189 <varname>Type=</varname> or
190 <varname>ExecStart=</varname> are
194 <option>dbus</option> is similar to
195 <option>simple</option>; however, it is
196 expected that the daemon acquires a
197 name on the D-Bus bus, as configured
199 <varname>BusName=</varname>. systemd
200 will proceed with starting follow-up
201 units after the D-Bus bus name has been
202 acquired. Service units with this
203 option configured implicitly gain
205 <filename>dbus.socket</filename>
206 unit. This type is the default if
207 <varname>BusName=</varname> is
211 <option>notify</option> is similar to
212 <option>simple</option>; however, it is
213 expected that the daemon sends a
214 notification message via
215 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
216 or an equivalent call when it has finished
217 starting up. systemd will proceed with
218 starting follow-up units after this
219 notification message has been sent. If
221 <varname>NotifyAccess=</varname> (see
222 below) should be set to open access to
223 the notification socket provided by
225 <varname>NotifyAccess=</varname> is
226 not set, it will be implicitly set to
227 <option>main</option>. Note that
229 <varname>Type=</varname><option>notify</option>
230 will not work if used in combination with
231 <varname>PrivateNetwork=</varname><option>yes</option>.</para>
234 <option>idle</option> is very similar
235 to <option>simple</option>; however,
236 actual execution of the service
237 binary is delayed until all jobs are
238 dispatched. This may be used to avoid
239 interleaving of output of shell
240 services with the status output on the
246 <term><varname>RemainAfterExit=</varname></term>
248 <listitem><para>Takes a boolean value
249 that specifies whether the service
250 shall be considered active even when
251 all its processes exited. Defaults to
252 <option>no</option>.</para>
257 <term><varname>GuessMainPID=</varname></term>
259 <listitem><para>Takes a boolean value
260 that specifies whether systemd should
261 try to guess the main PID of a service
262 if it cannot be determined
263 reliably. This option is ignored
264 unless <option>Type=forking</option>
265 is set and <option>PIDFile=</option>
266 is unset because for the other types
267 or with an explicitly configured PID
268 file, the main PID is always known. The
269 guessing algorithm might come to
270 incorrect conclusions if a daemon
271 consists of more than one process. If
272 the main PID cannot be determined,
273 failure detection and automatic
274 restarting of a service will not work
275 reliably. Defaults to
276 <option>yes</option>.</para>
281 <term><varname>PIDFile=</varname></term>
283 <listitem><para>Takes an absolute file
284 name pointing to the PID file of this
285 daemon. Use of this option is
286 recommended for services where
287 <varname>Type=</varname> is set to
288 <option>forking</option>. systemd will
289 read the PID of the main process of
290 the daemon after start-up of the
291 service. systemd will not write to the
292 file configured here.</para>
297 <term><varname>BusName=</varname></term>
299 <listitem><para>Takes a D-Bus bus
300 name that this service is reachable
301 as. This option is mandatory for
303 <varname>Type=</varname> is set to
304 <option>dbus</option>, but its use
305 is otherwise recommended if the process
306 takes a name on the D-Bus bus.</para>
311 <term><varname>ExecStart=</varname></term>
312 <listitem><para>Commands with their
313 arguments that are executed when this
314 service is started. For each of the
315 specified commands, the first argument
316 must be an absolute and literal path
317 to an executable.</para>
319 <para>When <varname>Type</varname> is
320 not <option>oneshot</option>, only one
321 command may and must be given. When
322 <varname>Type=oneshot</varname> is
323 used, none or more than one command
324 may be specified. Multiple command
325 lines may be concatenated in a single
326 directive by separating them with
327 semicolons (these semicolons must be
329 words). Alternatively, this directive
330 may be specified more than once with
331 the same effect. Lone semicolons may
333 <literal>\;</literal>. If the empty
334 string is assigned to this option, the
335 list of commands to start is reset,
336 prior assignments of this option will
337 have no effect. If no
338 <varname>ExecStart=</varname> is
339 specified, then the service must have
340 <varname>RemainAfterExit=yes</varname>
343 <para>Each command line is split on
344 whitespace, with the first item being
345 the command to execute, and the
346 subsequent items being the arguments.
347 Double quotes ("...") and single
348 quotes ('...') may be used, in which
349 case everything until the next
350 matching quote becomes part of the
351 same argument. Quotes themselves are
352 removed after parsing. In addition, a
354 (<literal>\</literal>) may be used to
355 merge lines. This syntax is intended
356 to be very similar to shell syntax,
357 but only the meta-characters and
358 expansions described in the following
359 paragraphs are understood.
360 Specifically, redirection using
361 <literal><</literal>,
362 <literal><<</literal>,
363 <literal>></literal>, and
364 <literal>>></literal>, pipes
365 using <literal>|</literal>, and
366 running programs in the background
367 using <literal>&</literal>
368 and <emphasis>other elements of shell
369 syntax are not supported</emphasis>.
372 <para>If more than one command is
373 specified, the commands are invoked
374 sequentially in the order they appear
375 in the unit file. If one of the
376 commands fails (and is not prefixed
377 with <literal>-</literal>), other lines
378 are not executed, and the unit is
379 considered failed.</para>
382 <varname>Type=forking</varname> is
383 set, the process started via this
384 command line will be considered the
385 main process of the daemon.</para>
387 <para>The command line accepts
388 <literal>%</literal> specifiers as
390 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
391 Note that the first argument of the
392 command line (i.e. the program to
393 execute) may not include
396 <para>Basic environment variable
397 substitution is supported. Use
398 <literal>${FOO}</literal> as part of a
399 word, or as a word of its own, on the
400 command line, in which case it will be
401 replaced by the value of the
402 environment variable including all
403 whitespace it contains, resulting in a
405 <literal>$FOO</literal> as a separate
406 word on the command line, in which
407 case it will be replaced by the value
408 of the environment variable split at
409 whitespace, resulting in zero or more
410 arguments. To pass a literal dollar
411 sign, use <literal>$$</literal>.
412 Variables whose value is not known at
413 expansion time are treated as empty
414 strings. Note that the first argument
415 (i.e. the program to execute) may not
416 be a variable.</para>
418 <para>Variables to be used in this
419 fashion may be defined through
420 <varname>Environment=</varname> and
421 <varname>EnvironmentFile=</varname>.
422 In addition, variables listed in the
423 section "Environment variables in
424 spawned processes" in
425 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
426 which are considered "static
427 configuration", may be used (this includes
428 e.g. <varname>$USER</varname>, but not
429 <varname>$TERM</varname>).</para>
431 <para>Optionally, if the absolute file
432 name is prefixed with
433 <literal>@</literal>, the second token
435 <literal>argv[0]</literal> to the
436 executed process, followed by the
437 further arguments specified. If the
438 absolute filename is prefixed with
439 <literal>-</literal>, an exit code of
440 the command normally considered a
441 failure (i.e. non-zero exit status or
442 abnormal exit due to signal) is ignored
443 and considered success. If both
444 <literal>-</literal> and
445 <literal>@</literal> are used, they
446 can appear in either order.</para>
448 <para>Note that this setting does not
449 directly support shell command
450 lines. If shell command lines are to
451 be used, they need to be passed
452 explicitly to a shell implementation
453 of some kind. Example:</para>
454 <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'</programlisting>
455 <para>Example:</para>
456 <programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"</programlisting>
457 <para>This will execute
458 <command>/bin/echo</command> two
459 times, each time with one argument:
460 <literal>one</literal> and
461 <literal>two two</literal>,
462 respectively. Because two commands are
464 <varname>Type=oneshot</varname> must
467 <para>Example:</para>
468 <programlisting>ExecStart=/bin/echo / >/dev/null & \; \
469 /bin/ls</programlisting>
470 <para>This will execute
471 <command>/bin/echo</command> with five
472 arguments: <literal>/</literal>,
473 <literal>>/dev/null</literal>,
474 <literal>&</literal>,
475 <literal>;</literal>, and
476 <literal>/bin/ls</literal>.</para>
478 <para>Example:</para>
479 <programlisting>Environment="ONE=one" 'TWO=two two'
480 ExecStart=/bin/echo $ONE $TWO ${TWO}</programlisting>
481 <para>This will execute
482 <command>/bin/echo</command> with four
483 arguments: <literal>one</literal>,
484 <literal>two</literal>,
485 <literal>two</literal>, and
486 <literal>two two</literal>.</para>
491 <term><varname>ExecStartPre=</varname></term>
492 <term><varname>ExecStartPost=</varname></term>
493 <listitem><para>Additional commands
494 that are executed before or after
496 <varname>ExecStart=</varname>, respectively.
497 Syntax is the same as for
498 <varname>ExecStart=</varname>, except
499 that multiple command lines are allowed
500 and the commands are executed one
501 after the other, serially.</para>
503 <para>If any of those commands (not
504 prefixed with <literal>-</literal>)
505 fail, the rest are not executed and
506 the unit is considered failed.</para>
511 <term><varname>ExecReload=</varname></term>
512 <listitem><para>Commands to execute to
513 trigger a configuration reload in the
514 service. This argument takes multiple
515 command lines, following the same
516 scheme as described for
517 <varname>ExecStart=</varname>
518 above. Use of this setting is
519 optional. Specifier and environment
520 variable substitution is supported
521 here following the same scheme as for
522 <varname>ExecStart=</varname>.</para>
524 <para>One additional, special
525 environment variable is set: if known,
526 <varname>$MAINPID</varname> is set to
527 the main process of the daemon, and
528 may be used for command lines like the
531 <programlisting>/bin/kill -HUP $MAINPID</programlisting>
533 <para>Note however that reloading a
534 daemon by sending a signal (as with
535 the example line above) is usually not
536 a good choice, because this is an
537 asynchronous operation and hence not
538 suitable to order reloads of multiple
539 services against each other. It is
540 strongly recommended to set
541 <varname>ExecReload=</varname> to a
542 command that not only triggers a
543 configuration reload of the daemon,
544 but also synchronously waits for it to
550 <term><varname>ExecStop=</varname></term>
551 <listitem><para>Commands to execute to
552 stop the service started via
553 <varname>ExecStart=</varname>. This
554 argument takes multiple command lines,
555 following the same scheme as described
556 for <varname>ExecStart=</varname>
557 above. Use of this setting is
558 optional. After the commands configured
559 in this option are run, all processes
560 remaining for a service are
561 terminated according to the
562 <varname>KillMode=</varname> setting
564 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
565 this option is not specified, the
566 process is terminated immediately when
567 service stop is requested. Specifier
568 and environment variable substitution
569 is supported (including
570 <varname>$MAINPID</varname>, see
571 above).</para></listitem>
575 <term><varname>ExecStopPost=</varname></term>
576 <listitem><para>Additional commands
577 that are executed after the service
578 was stopped. This includes cases where
579 the commands configured in
580 <varname>ExecStop=</varname> were used,
581 where the service does not have any
582 <varname>ExecStop=</varname> defined, or
583 where the service exited unexpectedly. This
584 argument takes multiple command lines,
585 following the same scheme as described
586 for <varname>ExecStart</varname>. Use
588 optional. Specifier and environment
589 variable substitution is
590 supported.</para></listitem>
594 <term><varname>RestartSec=</varname></term>
595 <listitem><para>Configures the time to
596 sleep before restarting a service (as
598 <varname>Restart=</varname>). Takes a
599 unit-less value in seconds, or a time
600 span value such as "5min
602 100ms.</para></listitem>
606 <term><varname>TimeoutStartSec=</varname></term>
607 <listitem><para>Configures the time to
608 wait for start-up. If a
609 daemon service does not signal
610 start-up completion within the
611 configured time, the service will be
612 considered failed and will be shut
614 Takes a unit-less value in seconds, or a
615 time span value such as "5min
616 20s". Pass <literal>0</literal> to
617 disable the timeout logic. Defaults to
618 <varname>DefaultTimeoutStartSec=</varname> from
619 the manager configuration file, except
620 when <varname>Type=oneshot</varname> is
621 used, in which case the timeout
622 is disabled by default
623 (see <citerefentry><refentrytitle>systemd-systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
628 <term><varname>TimeoutStopSec=</varname></term>
629 <listitem><para>Configures the time to
630 wait for stop. If a service is asked
631 to stop, but does not terminate in the
632 specified time, it will be terminated
633 forcibly via <constant>SIGTERM</constant>,
634 and after another timeout of equal duration
635 with <constant>SIGKILL</constant> (see
636 <varname>KillMode=</varname>
637 in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
638 Takes a unit-less value in seconds, or a
639 time span value such as "5min
640 20s". Pass <literal>0</literal> to disable
641 the timeout logic. Defaults to
642 <varname>DefaultTimeoutStopSec=</varname> from the
643 manager configuration file
644 (see <citerefentry><refentrytitle>systemd-systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
649 <term><varname>TimeoutSec=</varname></term>
650 <listitem><para>A shorthand for configuring
651 both <varname>TimeoutStartSec=</varname>
652 and <varname>TimeoutStopSec=</varname>
653 to the specified value.
658 <term><varname>WatchdogSec=</varname></term>
659 <listitem><para>Configures the
660 watchdog timeout for a service. The
661 watchdog is activated when the start-up is
662 completed. The service must call
663 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
664 regularly with <literal>WATCHDOG=1</literal>
665 (i.e. the "keep-alive ping"). If the time
666 between two such calls is larger than
667 the configured time, then the service
668 is placed in a failed state. By
669 setting <varname>Restart=</varname> to
670 <option>on-failure</option> or
671 <option>always</option>, the service
672 will be automatically restarted. The
673 time configured here will be passed to
674 the executed service process in the
675 <varname>WATCHDOG_USEC=</varname>
676 environment variable. This allows
677 daemons to automatically enable the
678 keep-alive pinging logic if watchdog
679 support is enabled for the service. If
681 <varname>NotifyAccess=</varname> (see
682 below) should be set to open access to
683 the notification socket provided by
685 <varname>NotifyAccess=</varname> is
686 not set, it will be implicitly set to
687 <option>main</option>. Defaults to 0,
689 feature.</para></listitem>
693 <term><varname>Restart=</varname></term>
694 <listitem><para>Configures whether the
695 service shall be restarted when the
696 service process exits, is killed,
697 or a timeout is reached. The service
698 process may be the main service
699 process, but it may also be one of the
700 processes specified with
701 <varname>ExecStartPre=</varname>,
702 <varname>ExecStartPost=</varname>,
703 <varname>ExecStop=</varname>,
704 <varname>ExecStopPost=</varname>, or
705 <varname>ExecReload=</varname>.
706 When the death of the process is a
707 result of systemd operation (e.g. service
708 stop or restart), the service will not be
709 restarted. Timeouts include missing
710 the watchdog "keep-alive ping"
711 deadline and a service start, reload,
712 and stop operation timeouts.</para>
716 <option>on-success</option>,
717 <option>on-failure</option>,
718 <option>on-abnormal</option>,
719 <option>on-watchdog</option>,
720 <option>on-abort</option>, or
721 <option>always</option>. If set to
722 <option>no</option> (the default), the
723 service will not be restarted. If set
724 to <option>on-success</option>, it
725 will be restarted only when the
726 service process exits cleanly. In
727 this context, a clean exit means an
728 exit code of 0, or one of the signals
729 <constant>SIGHUP</constant>,
730 <constant>SIGINT</constant>,
731 <constant>SIGTERM</constant> or
732 <constant>SIGPIPE</constant>, and
733 additionally, exit statuses and
735 <varname>SuccessExitStatus=</varname>.
736 If set to <option>on-failure</option>,
737 the service will be restarted when the
738 process exits with a non-zero exit
739 code, is terminated by a signal
740 (including on core dump, but excluding
741 the aforementiond four signals), when
742 an operation (such as service reload)
743 times out, and when the configured
744 watchdog timeout is triggered. If set
745 to <option>on-abnormal</option>, the
746 service will be restarted when the
747 process is terminated by a signal
748 (including on core dump, excluding the
749 aforementioned four signals), when an
750 operation times out, or when the
751 watchdog timeout is triggered. If set
752 to <option>on-abort</option>, the
753 service will be restarted only if the
754 service process exits due to an
755 uncaught signal not specified as a
756 clean exit status. If set to
757 <option>on-watchdog</option>, the
758 service will be restarted only if the
759 watchdog timeout for the service
761 <option>always</option>, the service
762 will be restarted regardless of
763 whether it exited cleanly or not, got
764 terminated abnormally by a signal, or
765 hit a timeout.</para>
768 <title>Exit causes and the effect of the <varname>Restart=</varname> settings on them</title>
771 <colspec colname='path' />
772 <colspec colname='expl' />
775 <entry>Restart settings/Exit causes</entry>
776 <entry><option>no</option></entry>
777 <entry><option>always</option></entry>
778 <entry><option>on-success</option></entry>
779 <entry><option>on-failure</option></entry>
780 <entry><option>on-abnormal</option></entry>
781 <entry><option>on-abort</option></entry>
782 <entry><option>on-watchdog</option></entry>
787 <entry>Clean exit code or signal</entry>
797 <entry>Unclean exit code</entry>
807 <entry>Unclean signal</entry>
817 <entry>Timeout</entry>
827 <entry>Watchdog</entry>
840 <para>As exceptions to the setting
841 above the service will not be
842 restarted if the exit code or signal
844 <varname>RestartPreventExitStatus=</varname>
845 (see below). Also, the services will
846 always be restarted if the exit code
847 or signal is specified in
848 <varname>RestartForceExitStatus=</varname>
851 <para>Setting this to
852 <option>on-failure</option> is the
853 recommended choice for long-running
854 services, in order to increase
855 reliability by attempting automatic
856 recovery from errors. For services
857 that shall be able to terminate on
858 their own choice (and avoid
859 immediate restarting),
860 <option>on-abnormal</option> is an
861 alternative choice.</para>
866 <term><varname>SuccessExitStatus=</varname></term>
867 <listitem><para>Takes a list of exit
868 status definitions that when returned
869 by the main service process will be
870 considered successful termination, in
871 addition to the normal successful exit
872 code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
873 <constant>SIGTERM</constant>, and <constant>SIGPIPE</constant>. Exit status
874 definitions can either be numeric exit
875 codes or termination signal names,
876 separated by spaces. For example:
877 <programlisting>SuccessExitStatus=1 2 8 SIGKILL</programlisting>
878 ensures that exit codes 1, 2, 8 and
879 the termination signal
880 <constant>SIGKILL</constant> are
881 considered clean service terminations.
884 <para>Note that if a process has a
885 signal handler installed and exits by
887 <citerefentry><refentrytitle>_exit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
888 in response to a signal, the
889 information about the signal is lost.
890 Programs should instead perform cleanup and kill themselves with the same signal instead. See
891 <ulink url="http://www.cons.org/cracauer/sigint.html">Proper handling of SIGINT/SIGQUIT — How to be a proper program</ulink>.</para>
893 <para>This option may appear more than once,
894 in which case the list of successful
895 exit statuses is merged. If the empty
896 string is assigned to this option, the
897 list is reset, all prior assignments
898 of this option will have no
899 effect.</para></listitem>
903 <term><varname>RestartPreventExitStatus=</varname></term>
904 <listitem><para>Takes a list of exit
905 status definitions that when returned
906 by the main service process will
907 prevent automatic service restarts,
908 regardless of the restart setting
910 <varname>Restart=</varname>. Exit
911 status definitions can either be
912 numeric exit codes or termination
913 signal names, and are separated by
914 spaces. Defaults to the empty list, so
915 that, by default, no exit status is
916 excluded from the configured restart
918 <programlisting>RestartPreventExitStatus=1 6 SIGABRT</programlisting> ensures that exit
919 codes 1 and 6 and the termination
920 signal <constant>SIGABRT</constant> will
921 not result in automatic service
923 option may appear more than once, in
924 which case the list of restart-preventing
925 statuses is merged. If the empty
926 string is assigned to this option, the
927 list is reset and all prior assignments
928 of this option will have no
929 effect.</para></listitem>
933 <term><varname>RestartForceExitStatus=</varname></term>
934 <listitem><para>Takes a list of exit
935 status definitions that when returned
936 by the main service process will force
937 automatic service restarts, regardless
938 of the restart setting configured with
939 <varname>Restart=</varname>. The
940 argument format is similar to
941 <varname>RestartPreventExitStatus=</varname>.</para></listitem>
945 <term><varname>PermissionsStartOnly=</varname></term>
946 <listitem><para>Takes a boolean
947 argument. If true, the permission-related
948 execution options, as
950 <varname>User=</varname> and similar
952 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
953 for more information), are only applied
954 to the process started with
955 <varname>ExecStart=</varname>, and not
957 <varname>ExecStartPre=</varname>,
958 <varname>ExecStartPost=</varname>,
959 <varname>ExecReload=</varname>,
960 <varname>ExecStop=</varname>, and
961 <varname>ExecStopPost=</varname>
962 commands. If false, the setting is
963 applied to all configured commands the
964 same way. Defaults to
965 false.</para></listitem>
969 <term><varname>RootDirectoryStartOnly=</varname></term>
970 <listitem><para>Takes a boolean
971 argument. If true, the root directory,
972 as configured with the
973 <varname>RootDirectory=</varname>
975 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
976 for more information), is only applied
977 to the process started with
978 <varname>ExecStart=</varname>, and not
980 <varname>ExecStartPre=</varname>,
981 <varname>ExecStartPost=</varname>,
982 <varname>ExecReload=</varname>,
983 <varname>ExecStop=</varname>, and
984 <varname>ExecStopPost=</varname>
985 commands. If false, the setting is
986 applied to all configured commands the
987 same way. Defaults to
988 false.</para></listitem>
992 <term><varname>NonBlocking=</varname></term>
993 <listitem><para>Set the
994 <constant>O_NONBLOCK</constant> flag
995 for all file descriptors passed via
996 socket-based activation. If true, all
997 file descriptors >= 3 (i.e. all except
998 stdin, stdout, and stderr) will have
999 the <constant>O_NONBLOCK</constant> flag
1000 set and hence are in
1001 non-blocking mode. This option is only
1002 useful in conjunction with a socket
1003 unit, as described in
1004 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
1005 to false.</para></listitem>
1009 <term><varname>NotifyAccess=</varname></term>
1010 <listitem><para>Controls access to the
1011 service status notification socket, as
1013 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
1015 <option>none</option> (the default),
1016 <option>main</option> or
1017 <option>all</option>. If
1018 <option>none</option>, no daemon status
1019 updates are accepted from the service
1020 processes, all status update messages
1021 are ignored. If <option>main</option>,
1022 only service updates sent from the
1023 main process of the service are
1024 accepted. If <option>all</option>, all
1025 services updates from all members of
1026 the service's control group are
1027 accepted. This option should be set to
1028 open access to the notification socket
1030 <varname>Type=notify</varname> or
1031 <varname>WatchdogSec=</varname> (see
1032 above). If those options are used but
1033 <varname>NotifyAccess=</varname> is not
1034 configured, it will be implicitly set
1036 <option>main</option>.</para></listitem>
1040 <term><varname>Sockets=</varname></term>
1041 <listitem><para>Specifies the name of
1042 the socket units this service shall
1043 inherit the sockets from when the
1044 service is started. Normally it
1045 should not be necessary to use this
1046 setting as all sockets whose unit
1047 shares the same name as the service
1048 (ignoring the different suffix of course)
1049 are passed to the spawned
1052 <para>Note that the same socket may be
1053 passed to multiple processes at the
1054 same time. Also note that a different
1055 service may be activated on incoming
1056 traffic than that which inherits the
1057 sockets. Or in other words: the
1058 <varname>Service=</varname> setting of
1059 <filename>.socket</filename> units
1060 does not have to match the inverse of
1061 the <varname>Sockets=</varname>
1063 <filename>.service</filename> it
1066 <para>This option may appear more than
1067 once, in which case the list of socket
1068 units is merged. If the empty string
1069 is assigned to this option, the list of
1070 sockets is reset, and all prior uses of
1071 this setting will have no
1072 effect.</para></listitem>
1076 <term><varname>StartLimitInterval=</varname></term>
1077 <term><varname>StartLimitBurst=</varname></term>
1079 <listitem><para>Configure service
1080 start rate limiting. By default,
1081 services which are started more
1082 than 5 times within 10 seconds are not
1083 permitted to start any more times
1084 until the 10 second interval ends. With
1085 these two options, this rate limiting
1086 may be modified. Use
1087 <varname>StartLimitInterval=</varname>
1088 to configure the checking interval (defaults to
1089 <varname>DefaultStartLimitInterval=</varname> in
1090 manager configuration file, set to 0 to disable
1091 any kind of rate limiting). Use
1092 <varname>StartLimitBurst=</varname> to
1093 configure how many starts per interval
1094 are allowed (defaults to
1095 <varname>DefaultStartLimitBurst=</varname> in
1096 manager configuration file). These
1097 configuration options are particularly
1098 useful in conjunction with
1099 <varname>Restart=</varname>; however,
1100 they apply to all kinds of starts
1101 (including manual), not just those
1103 <varname>Restart=</varname> logic.
1104 Note that units which are configured
1105 for <varname>Restart=</varname> and
1106 which reach the start limit are not
1107 attempted to be restarted anymore;
1108 however, they may still be restarted
1109 manually at a later point, from which
1110 point on, the restart logic is again
1111 activated. Note that
1113 reset-failed</command> will cause the
1114 restart rate counter for a service to
1115 be flushed, which is useful if the
1116 administrator wants to manually start
1117 a service and the start limit
1119 that.</para></listitem>
1123 <term><varname>StartLimitAction=</varname></term>
1125 <listitem><para>Configure the action
1126 to take if the rate limit configured
1128 <varname>StartLimitInterval=</varname>
1130 <varname>StartLimitBurst=</varname> is
1132 <option>none</option>,
1133 <option>reboot</option>,
1134 <option>reboot-force</option>,
1135 <option>reboot-immediate</option>,
1136 <option>poweroff</option>,
1137 <option>poweroff-force</option> or
1138 <option>poweroff-immediate</option>. If
1139 <option>none</option> is set, hitting
1140 the rate limit will trigger no action
1141 besides that the start will not be
1142 permitted. <option>reboot</option>
1143 causes a reboot following the normal
1144 shutdown procedure (i.e. equivalent to
1145 <command>systemctl reboot</command>).
1146 <option>reboot-force</option> causes a
1147 forced reboot which will terminate all
1148 processes forcibly but should cause no
1149 dirty file systems on reboot
1150 (i.e. equivalent to <command>systemctl
1151 reboot -f</command>) and
1152 <option>reboot-immediate</option>
1153 causes immediate execution of the
1154 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
1155 system call, which might result in
1157 <option>poweroff</option>,
1158 <option>poweroff-force</option>,
1159 <option>poweroff-immediate</option>
1160 have the effect of powering down the
1162 semantics. Defaults to
1163 <option>none</option>.</para></listitem>
1167 <term><varname>FailureAction=</varname></term>
1168 <listitem><para>Configure the action
1169 to take when the service enters a failed
1170 state. Takes the same values as
1171 <varname>StartLimitAction=</varname>
1172 and executes the same actions.
1173 Defaults to <option>none</option>.
1178 <term><varname>RebootArgument=</varname></term>
1179 <listitem><para>Configure the optional
1181 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
1183 <varname>StartLimitAction=</varname>
1184 or <varname>FailureAction=</varname>
1185 is a reboot action. This works just
1186 like the optional argument to
1187 <command>systemctl reboot</command>
1188 command.</para></listitem>
1194 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1196 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1197 for more settings.</para>
1202 <title>Compatibility Options</title>
1204 <para>The following options are also available in the
1205 <literal>[Service]</literal> section, but exist purely
1206 for compatibility reasons and should not be used in
1207 newly written service files.</para>
1209 <variablelist class='unit-directives'>
1211 <term><varname>SysVStartPriority=</varname></term>
1212 <listitem><para>Set the SysV start
1213 priority to use to order this service
1214 in relation to SysV services lacking
1215 LSB headers. This option is only
1216 necessary to fix ordering in relation
1217 to legacy SysV services that have no
1218 ordering information encoded in the
1219 script headers. As such, it should only
1220 be used as a temporary compatibility
1221 option and should not be used in new unit
1222 files. Almost always, it is a better
1223 choice to add explicit ordering
1225 <varname>After=</varname> or
1226 <varname>Before=</varname>,
1227 instead. For more details, see
1228 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1229 If used, pass an integer value in the
1230 range 0-99.</para></listitem>
1236 <title>See Also</title>
1238 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1239 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1240 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1241 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1242 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1243 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1244 <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>