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[elogind.git] / man / systemd.service.xml
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3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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9   Copyright 2010 Lennart Poettering
10
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24
25 <refentry id="systemd.service">
26         <refentryinfo>
27                 <title>systemd.service</title>
28                 <productname>systemd</productname>
29
30                 <authorgroup>
31                         <author>
32                                 <contrib>Developer</contrib>
33                                 <firstname>Lennart</firstname>
34                                 <surname>Poettering</surname>
35                                 <email>lennart@poettering.net</email>
36                         </author>
37                 </authorgroup>
38         </refentryinfo>
39
40         <refmeta>
41                 <refentrytitle>systemd.service</refentrytitle>
42                 <manvolnum>5</manvolnum>
43         </refmeta>
44
45         <refnamediv>
46                 <refname>systemd.service</refname>
47                 <refpurpose>Service unit configuration</refpurpose>
48         </refnamediv>
49
50         <refsynopsisdiv>
51                 <para><filename><replaceable>service</replaceable>.service</filename></para>
52         </refsynopsisdiv>
53
54         <refsect1>
55                 <title>Description</title>
56
57                 <para>A unit configuration file whose name ends in
58                 <filename>.service</filename> encodes information
59                 about a process controlled and supervised by
60                 systemd.</para>
61
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>
71
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
78                 terminated, and in
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>
82
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
96                 option.</para>
97
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.
109                 </para>
110         </refsect1>
111
112         <refsect1>
113                 <title>Options</title>
114
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>
122                 and
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>
126
127                 <variablelist class='unit-directives'>
128                         <varlistentry>
129                                 <term><varname>Type=</varname></term>
130
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>
139
140                                 <para>If set to
141                                 <option>simple</option> (the default
142                                 value if <varname>BusName=</varname>
143                                 is not specified), it is expected that
144                                 the process configured with
145                                 <varname>ExecStart=</varname> is the
146                                 main process of the service. In this
147                                 mode, if the process offers
148                                 functionality to other processes on
149                                 the system, its communication channels
150                                 should be installed before the daemon
151                                 is started up (e.g. sockets set up by
152                                 systemd, via socket activation), as
153                                 systemd will immediately proceed
154                                 starting follow-up units.</para>
155
156                                 <para>If set to
157                                 <option>forking</option>, it is
158                                 expected that the process configured
159                                 with <varname>ExecStart=</varname>
160                                 will call <function>fork()</function>
161                                 as part of its start-up. The parent process is
162                                 expected to exit when start-up is
163                                 complete and all communication
164                                 channels are set up. The child continues
165                                 to run as the main daemon
166                                 process. This is the behavior of
167                                 traditional UNIX daemons. If this
168                                 setting is used, it is recommended to
169                                 also use the
170                                 <varname>PIDFile=</varname> option, so
171                                 that systemd can identify the main
172                                 process of the daemon. systemd will
173                                 proceed starting follow-up units as
174                                 soon as the parent process
175                                 exits.</para>
176
177                                 <para>Behavior of
178                                 <option>oneshot</option> is similar
179                                 to <option>simple</option>, however
180                                 it is expected that the process has to
181                                 exit before systemd starts follow-up
182                                 units. <varname>RemainAfterExit=</varname>
183                                 is particularly useful for this type
184                                 of service.</para>
185
186                                 <para>Behavior of
187                                 <option>dbus</option> is similar to
188                                 <option>simple</option>, however it is
189                                 expected that the daemon acquires a
190                                 name on the D-Bus bus, as configured
191                                 by
192                                 <varname>BusName=</varname>. systemd
193                                 will proceed starting follow-up units
194                                 after the D-Bus bus name has been
195                                 acquired. Service units with this
196                                 option configured implicitly gain
197                                 dependencies on the
198                                 <filename>dbus.socket</filename>
199                                 unit. This type is the default if
200                                 <varname>BusName=</varname> is
201                                 specified.</para>
202
203                                 <para>Behavior of
204                                 <option>notify</option> is similar to
205                                 <option>simple</option>, however it is
206                                 expected that the daemon sends a
207                                 notification message via
208                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
209                                 or an equivalent call when it finished
210                                 starting up. systemd will proceed
211                                 starting follow-up units after this
212                                 notification message has been sent. If
213                                 this option is used,
214                                 <varname>NotifyAccess=</varname> (see
215                                 below) should be set to open access to
216                                 the notification socket provided by
217                                 systemd. If
218                                 <varname>NotifyAccess=</varname> is
219                                 not set, it will be implicitly set to
220                                 <option>main</option>. Note that
221                                 currently
222                                 <varname>Type=</varname><option>notify</option>
223                                 will not work if used in combination with
224                                 <varname>PrivateNetwork=</varname><option>yes</option>.</para>
225
226                                 <para>Behavior of
227                                 <option>idle</option> is very similar
228                                 to <option>simple</option>, however
229                                 actual execution of the service
230                                 binary is delayed until all jobs are
231                                 dispatched. This may be used to avoid
232                                 interleaving of output of shell
233                                 services with the status output on the
234                                 console.</para>
235                                 </listitem>
236                         </varlistentry>
237
238                         <varlistentry>
239                                 <term><varname>RemainAfterExit=</varname></term>
240
241                                 <listitem><para>Takes a boolean value
242                                 that specifies whether the service
243                                 shall be considered active even when
244                                 all its processes exited. Defaults to
245                                 <option>no</option>.</para>
246                                 </listitem>
247                         </varlistentry>
248
249                         <varlistentry>
250                                 <term><varname>GuessMainPID=</varname></term>
251
252                                 <listitem><para>Takes a boolean value
253                                 that specifies whether systemd should
254                                 try to guess the main PID of a service
255                                 if it cannot be determined
256                                 reliably. This option is ignored
257                                 unless <option>Type=forking</option>
258                                 is set and <option>PIDFile=</option>
259                                 is unset because for the other types
260                                 or with an explicitly configured PID
261                                 file the main PID is always known. The
262                                 guessing algorithm might come to
263                                 incorrect conclusions if a daemon
264                                 consists of more than one process. If
265                                 the main PID cannot be determined,
266                                 failure detection and automatic
267                                 restarting of a service will not work
268                                 reliably. Defaults to
269                                 <option>yes</option>.</para>
270                                 </listitem>
271                         </varlistentry>
272
273                         <varlistentry>
274                                 <term><varname>PIDFile=</varname></term>
275
276                                 <listitem><para>Takes an absolute file
277                                 name pointing to the PID file of this
278                                 daemon. Use of this option is
279                                 recommended for services where
280                                 <varname>Type=</varname> is set to
281                                 <option>forking</option>. systemd will
282                                 read the PID of the main process of
283                                 the daemon after start-up of the
284                                 service. systemd will not write to the
285                                 file configured here.</para>
286                                 </listitem>
287                         </varlistentry>
288
289                         <varlistentry>
290                                 <term><varname>BusName=</varname></term>
291
292                                 <listitem><para>Takes a D-Bus bus
293                                 name, that this service is reachable
294                                 as. This option is mandatory for
295                                 services where
296                                 <varname>Type=</varname> is set to
297                                 <option>dbus</option>, but its use
298                                 is otherwise recommended as well if
299                                 the process takes a name on the D-Bus
300                                 bus.</para>
301                                 </listitem>
302                         </varlistentry>
303
304                         <varlistentry>
305                                 <term><varname>ExecStart=</varname></term>
306                                 <listitem><para>Commands with their
307                                 arguments that are executed when this
308                                 service is started. For each of the
309                                 specified commands, the first argument
310                                 must be an absolute and literal path
311                                 to an executable.</para>
312
313                                 <para>When <varname>Type</varname> is
314                                 not <option>oneshot</option>, only one
315                                 command may be given. When
316                                 <varname>Type=oneshot</varname> is
317                                 used, more than one command may be
318                                 specified. Multiple command lines may
319                                 be concatenated in a single directive,
320                                 by separating them with semicolons
321                                 (these semicolons must be passed as
322                                 separate words). Alternatively, this
323                                 directive may be specified more than
324                                 once with the same effect.
325                                 Lone semicolons may be escaped as
326                                 <literal>\;</literal>. If the empty
327                                 string is assigned to this option, the
328                                 list of commands to start is reset,
329                                 prior assignments of this option will
330                                 have no effect.</para>
331
332                                 <para>Each command line is split on
333                                 whitespace, with the first item being
334                                 the command to execute, and the
335                                 subsequent items being the arguments.
336                                 Double quotes ("...") and single
337                                 quotes ('...') may be used, in which
338                                 case everything until the next
339                                 matching quote becomes part of the
340                                 same argument. Quotes themselves are
341                                 removed after parsing. In addition, a
342                                 trailing backslash
343                                 (<literal>\</literal>) may be used to
344                                 merge lines. This syntax is intended
345                                 to be very similar to shell syntax,
346                                 but only the meta-characters and
347                                 expansions described in the following
348                                 paragraphs are understood.
349                                 Specifically, redirection using
350                                 <literal>&lt;</literal>,
351                                 <literal>&lt;&lt;</literal>,
352                                 <literal>&gt;</literal>, and
353                                 <literal>&gt;&gt;</literal>, pipes
354                                 using <literal>|</literal>, and
355                                 running programs in the background
356                                 using <literal>&amp;</literal>
357                                 and <emphasis>other elements of shell
358                                 syntax are not supported</emphasis>.
359                                 </para>
360
361                                 <para>If more than one command is
362                                 specified, the commands are invoked
363                                 one by one sequentially in the order
364                                 they appear in the unit file. If one
365                                 of the commands fails (and is not
366                                 prefixed with <literal>-</literal>),
367                                 other lines are not executed and the
368                                 unit is considered failed.</para>
369
370                                 <para>Unless
371                                 <varname>Type=forking</varname> is
372                                 set, the process started via this
373                                 command line will be considered the
374                                 main process of the daemon.</para>
375
376                                 <para>The command line accepts
377                                 <literal>%</literal> specifiers as
378                                 described in
379                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
380                                 Note that the first argument of the
381                                 command line (i.e. the program to
382                                 execute) may not include
383                                 specifiers.</para>
384
385                                 <para>Basic environment variable
386                                 substitution is supported. Use
387                                 <literal>${FOO}</literal> as part of a
388                                 word, or as a word of its own on the
389                                 command line, in which case it will be
390                                 replaced by the value of the
391                                 environment variable including all
392                                 whitespace it contains, resulting in a
393                                 single argument.  Use
394                                 <literal>$FOO</literal> as a separate
395                                 word on the command line, in which
396                                 case it will be replaced by the value
397                                 of the environment variable split up
398                                 at whitespace, resulting in zero or
399                                 more arguments. To pass a literal dollar sign,
400                                 use <literal>$$</literal>. Note that the first
401                                 argument (i.e. the program to execute)
402                                 may not be a variable.</para>
403
404                                 <para>Optionally, if the absolute file
405                                 name is prefixed with
406                                 <literal>@</literal>, the second token
407                                 will be passed as
408                                 <literal>argv[0]</literal> to the
409                                 executed process, followed by the
410                                 further arguments specified. If the
411                                 absolute filename is prefixed with
412                                 <literal>-</literal>, an exit code of
413                                 the command normally considered a
414                                 failure (i.e. non-zero exit status or
415                                 abnormal exit due to signal) is ignored
416                                 and considered success. If both
417                                 <literal>-</literal> and
418                                 <literal>@</literal> are used, they
419                                 can appear in either order.</para>
420
421                                 <para>Note that this setting does not
422                                 directly support shell command
423                                 lines. If shell command lines are to
424                                 be used, they need to be passed
425                                 explicitly to a shell implementation
426                                 of some kind. Example:</para>
427                                 <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'
428                                 </programlisting>
429
430                                 <para>Only select environment variables
431                                 are set for executed commands. See
432                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
433                                 </para>
434
435                                 <para>Example:</para>
436                                 <programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"
437                                 </programlisting>
438                                 <para>This will execute
439                                 <command>/bin/echo</command> two
440                                 times, each time with one argument,
441                                 <literal>one</literal> and
442                                 <literal>two two</literal>,
443                                 respectively. Since two commands are
444                                 specified
445                                 <varname>Type=oneshot</varname> must
446                                 be used.</para>
447
448                                 <para>Example:</para>
449                                 <programlisting>ExecStart=/bin/echo / &gt;/dev/null &amp; \; \
450 /bin/ls
451                                 </programlisting>
452                                 <para>This will execute
453                                 <command>/bin/echo</command> with five
454                                 arguments: <literal>/</literal>,
455                                 <literal>&gt;/dev/null</literal>,
456                                 <literal>&amp;</literal>,
457                                 <literal>;</literal>, and
458                                 <literal>/bin/ls</literal>.</para>
459
460                                 <para>Example:</para>
461                                 <programlisting>Environment="ONE=one" 'TWO=two two'
462 ExecStart=/bin/echo $ONE $TWO ${TWO}
463                                 </programlisting>
464                                 <para>This will execute
465                                 <command>/bin/echo</command> with four
466                                 arguments: <literal>one</literal>,
467                                 <literal>two</literal>,
468                                 <literal>two</literal>, and
469                                 <literal>two two</literal>.</para>
470                               </listitem>
471                         </varlistentry>
472
473                         <varlistentry>
474                                 <term><varname>ExecStartPre=</varname></term>
475                                 <term><varname>ExecStartPost=</varname></term>
476                                 <listitem><para>Additional commands
477                                 that are executed before or after
478                                 the command in
479                                 <varname>ExecStart=</varname>, respectively.
480                                 Syntax is the same as for
481                                 <varname>ExecStart=</varname>, except
482                                 that multiple command lines are allowed
483                                 and the commands are executed one
484                                 after the other, serially.</para>
485
486                                 <para>If any of those commands (not
487                                 prefixed with <literal>-</literal>)
488                                 fail, the rest are not executed and
489                                 the unit is considered failed.</para>
490                                 </listitem>
491                         </varlistentry>
492
493                         <varlistentry>
494                                 <term><varname>ExecReload=</varname></term>
495                                 <listitem><para>Commands to execute to
496                                 trigger a configuration reload in the
497                                 service. This argument takes multiple
498                                 command lines, following the same
499                                 scheme as described for
500                                 <varname>ExecStart=</varname>
501                                 above. Use of this setting is
502                                 optional. Specifier and environment
503                                 variable substitution is supported
504                                 here following the same scheme as for
505                                 <varname>ExecStart=</varname>.</para>
506
507                                 <para>One additional special
508                                 environment variables is set: if known
509                                 <varname>$MAINPID</varname> is set to
510                                 the main process of the daemon, and
511                                 may be used for command lines like the
512                                 following:</para>
513
514                                 <programlisting>/bin/kill -HUP $MAINPID</programlisting>
515                                 </listitem>
516                         </varlistentry>
517
518                         <varlistentry>
519                                 <term><varname>ExecStop=</varname></term>
520                                 <listitem><para>Commands to execute to
521                                 stop the service started via
522                                 <varname>ExecStart=</varname>. This
523                                 argument takes multiple command lines,
524                                 following the same scheme as described
525                                 for <varname>ExecStart=</varname>
526                                 above. Use of this setting is
527                                 optional. All processes remaining for
528                                 a service after the commands
529                                 configured in this option are run are
530                                 terminated according to the
531                                 <varname>KillMode=</varname> setting
532                                 (see
533                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
534                                 this option is not specified, the
535                                 process is terminated right-away when
536                                 service stop is requested. Specifier
537                                 and environment variable substitution
538                                 is supported (including
539                                 <varname>$MAINPID</varname>, see
540                                 above).</para></listitem>
541                         </varlistentry>
542
543                         <varlistentry>
544                                 <term><varname>ExecStopPost=</varname></term>
545                                 <listitem><para>Additional commands
546                                 that are executed after the service
547                                 was stopped. This includes cases where
548                                 the commands configured in
549                                 <varname>ExecStop=</varname> were used,
550                                 where the service does not have any
551                                 <varname>ExecStop=</varname> defined, or
552                                 where the service exited unexpectedly. This
553                                 argument takes multiple command lines,
554                                 following the same scheme as described
555                                 for <varname>ExecStart</varname>. Use
556                                 of these settings is
557                                 optional. Specifier and environment
558                                 variable substitution is
559                                 supported.</para></listitem>
560                         </varlistentry>
561
562                         <varlistentry>
563                                 <term><varname>RestartSec=</varname></term>
564                                 <listitem><para>Configures the time to
565                                 sleep before restarting a service (as
566                                 configured with
567                                 <varname>Restart=</varname>). Takes a
568                                 unit-less value in seconds, or a time
569                                 span value such as "5min
570                                 20s". Defaults to
571                                 100ms.</para></listitem>
572                         </varlistentry>
573
574                         <varlistentry>
575                                 <term><varname>TimeoutStartSec=</varname></term>
576                                 <listitem><para>Configures the time to
577                                 wait for start-up. If a
578                                 daemon service does not signal
579                                 start-up completion within the
580                                 configured time, the service will be
581                                 considered failed and be shut down
582                                 again.
583                                 Takes a unit-less value in seconds, or a
584                                 time span value such as "5min
585                                 20s". Pass 0 to disable the timeout
586                                 logic. Defaults to <varname>TimeoutStartSec=</varname> from the
587                                 manager configuration file, except when
588                                 <varname>Type=oneshot</varname> is
589                                 used, in which case the timeout
590                                 is disabled by default.
591                                 </para></listitem>
592                         </varlistentry>
593
594                         <varlistentry>
595                                 <term><varname>TimeoutStopSec=</varname></term>
596                                 <listitem><para>Configures the time to
597                                 wait for stop. If a service is asked
598                                 to stop but does not terminate in the
599                                 specified time, it will be terminated
600                                 forcibly via <constant>SIGTERM</constant>, and after
601                                 another delay of this time with
602                                 <constant>SIGKILL</constant> (See
603                                 <varname>KillMode=</varname>
604                                 in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
605                                 Takes a unit-less value in seconds, or a
606                                 time span value such as "5min
607                                 20s". Pass 0 to disable the timeout
608                                 logic. Defaults to <varname>TimeoutStartSec=</varname> from the
609                                 manager configuration file.
610                                 </para></listitem>
611                         </varlistentry>
612
613                         <varlistentry>
614                                 <term><varname>TimeoutSec=</varname></term>
615                                 <listitem><para>A shorthand for configuring
616                                 both <varname>TimeoutStartSec=</varname>
617                                 and <varname>TimeoutStopSec=</varname>
618                                 to the specified value.
619                                 </para></listitem>
620                         </varlistentry>
621
622                         <varlistentry>
623                                 <term><varname>WatchdogSec=</varname></term>
624                                 <listitem><para>Configures the
625                                 watchdog timeout for a service. The
626                                 watchdog is activated when the start-up is
627                                 completed. The service must call
628                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
629                                 regularly with "WATCHDOG=1" (i.e. the
630                                 "keep-alive ping"). If the time
631                                 between two such calls is larger than
632                                 the configured time, then the service
633                                 is placed in a failure state. By
634                                 setting <varname>Restart=</varname> to
635                                 <option>on-failure</option> or
636                                 <option>always</option>, the service
637                                 will be automatically restarted. The
638                                 time configured here will be passed to
639                                 the executed service process in the
640                                 <varname>WATCHDOG_USEC=</varname>
641                                 environment variable. This allows
642                                 daemons to automatically enable the
643                                 keep-alive pinging logic if watchdog
644                                 support is enabled for the service. If
645                                 this option is used,
646                                 <varname>NotifyAccess=</varname> (see
647                                 below) should be set to open access to
648                                 the notification socket provided by
649                                 systemd. If
650                                 <varname>NotifyAccess=</varname> is
651                                 not set, it will be implicitly set to
652                                 <option>main</option>. Defaults to 0,
653                                 which disables this
654                                 feature.</para></listitem>
655                         </varlistentry>
656
657                         <varlistentry>
658                                 <term><varname>Restart=</varname></term>
659                                 <listitem><para>Configures whether the
660                                 service shall be restarted when the
661                                 service process exits, is killed,
662                                 or a timeout is reached. The service
663                                 process may be the main service
664                                 process, but also one of the processes
665                                 specified with
666                                 <varname>ExecStartPre=</varname>,
667                                 <varname>ExecStartPost=</varname>,
668                                 <varname>ExecStopPre=</varname>,
669                                 <varname>ExecStopPost=</varname>, or
670                                 <varname>ExecReload=</varname>.
671                                 When the death of the process is a
672                                 result of systemd operation (e.g. service
673                                 stop or restart), the service will not be
674                                 restarted. Timeouts include missing
675                                 the watchdog "keep-alive ping"
676                                 deadline and a service start, reload,
677                                 and stop operation timeouts.</para>
678
679                                 <para>Takes one of
680                                 <option>no</option>,
681                                 <option>on-success</option>,
682                                 <option>on-failure</option>,
683                                 <option>on-watchdog</option>,
684                                 <option>on-abort</option>, or
685                                 <option>always</option>. If set to
686                                 <option>no</option> (the default), the
687                                 service will not be restarted. If set to
688                                 <option>on-success</option>, it will be
689                                 restarted only when the service process
690                                 exits cleanly.
691                                 In this context, a clean exit means
692                                 an exit code of 0, or one of the signals
693                                 <constant>SIGHUP</constant>, <constant>SIGINT</constant>, <constant>SIGTERM</constant>, or <constant>SIGPIPE</constant>, and
694                                 additionally, exit statuses and signals
695                                 specified in <varname>SuccessExitStatus=</varname>.
696                                 If set to <option>on-failure</option>,
697                                 the service will be restarted when the
698                                 process exits with an nonzero exit code,
699                                 is terminated by a signal (including on
700                                 core dump), when an operation (such as
701                                 service reload) times out, and when the
702                                 configured watchdog timeout is triggered.
703                                 If set to
704                                 <option>on-abort</option>, the service
705                                 will be restarted only if the service
706                                 process exits due to an uncaught
707                                 signal not specified as a clean exit
708                                 status.
709                                 If set to
710                                 <option>on-watchdog</option>, the service
711                                 will be restarted only if the watchdog
712                                 timeout for the service expires.
713                                 If set to
714                                 <option>always</option>, the service
715                                 will be restarted regardless whether
716                                 it exited cleanly or not, got
717                                 terminated abnormally by a signal or
718                                 hit a timeout.</para>
719
720                                 <para>In addition to the above settings,
721                                 the service will not be restarted if the
722                                 exit code or signal is specified in
723                                 <varname>RestartPreventExitStatus=</varname>
724                                 (see below).</para></listitem>
725                         </varlistentry>
726
727                         <varlistentry>
728                                 <term><varname>SuccessExitStatus=</varname></term>
729                                 <listitem><para>Takes a list of exit
730                                 status definitions that when returned
731                                 by the main service process will be
732                                 considered successful termination, in
733                                 addition to the normal successful exit
734                                 code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
735                                 <constant>SIGTERM</constant> and <constant>SIGPIPE</constant>. Exit status
736                                 definitions can either be numeric exit
737                                 codes or termination signal names,
738                                 separated by spaces. Example:
739                                 <literal>SuccessExitStatus=1 2 8
740                                 <constant>SIGKILL</constant></literal>, ensures that exit
741                                 codes 1, 2, 8 and the termination
742                                 signal <constant>SIGKILL</constant> are considered clean
743                                 service terminations. This option may
744                                 appear more than once in which case
745                                 the list of successful exit statuses
746                                 is merged. If the empty string is
747                                 assigned to this option, the list is
748                                 reset, all prior assignments of this
749                                 option will have no
750                                 effect.</para></listitem>
751                         </varlistentry>
752
753                         <varlistentry>
754                                 <term><varname>RestartPreventExitStatus=</varname></term>
755                                 <listitem><para>Takes a list of exit
756                                 status definitions that when returned
757                                 by the main service process will
758                                 prevent automatic service restarts
759                                 regardless of the restart setting
760                                 configured with
761                                 <varname>Restart=</varname>. Exit
762                                 status definitions can either be
763                                 numeric exit codes or termination
764                                 signal names, and are separated by
765                                 spaces. Defaults to the empty list, so
766                                 that by default no exit status is
767                                 excluded from the configured restart
768                                 logic. Example:
769                                 <literal>RestartPreventExitStatus=1 6
770                                 SIGABRT</literal>, ensures that exit
771                                 codes 1 and 6 and the termination
772                                 signal SIGABRT will not result in
773                                 automatic service restarting. This
774                                 option may appear more than once in
775                                 which case the list of restart preventing
776                                 statuses is merged. If the empty
777                                 string is assigned to this option, the
778                                 list is reset, all prior assignments
779                                 of this option will have no
780                                 effect.</para></listitem>
781                         </varlistentry>
782
783                         <varlistentry>
784                                 <term><varname>PermissionsStartOnly=</varname></term>
785                                 <listitem><para>Takes a boolean
786                                 argument. If true, the permission
787                                 related execution options as
788                                 configured with
789                                 <varname>User=</varname> and similar
790                                 options (see
791                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
792                                 for more information) are only applied
793                                 to the process started with
794                                 <varname>ExecStart=</varname>, and not
795                                 to the various other
796                                 <varname>ExecStartPre=</varname>,
797                                 <varname>ExecStartPost=</varname>,
798                                 <varname>ExecReload=</varname>,
799                                 <varname>ExecStop=</varname>,
800                                 <varname>ExecStopPost=</varname>
801                                 commands. If false, the setting is
802                                 applied to all configured commands the
803                                 same way. Defaults to
804                                 false.</para></listitem>
805                         </varlistentry>
806
807                         <varlistentry>
808                                 <term><varname>RootDirectoryStartOnly=</varname></term>
809                                 <listitem><para>Takes a boolean
810                                 argument. If true, the root directory
811                                 as configured with the
812                                 <varname>RootDirectory=</varname>
813                                 option (see
814                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
815                                 for more information) is only applied
816                                 to the process started with
817                                 <varname>ExecStart=</varname>, and not
818                                 to the various other
819                                 <varname>ExecStartPre=</varname>,
820                                 <varname>ExecStartPost=</varname>,
821                                 <varname>ExecReload=</varname>,
822                                 <varname>ExecStop=</varname>,
823                                 <varname>ExecStopPost=</varname>
824                                 commands. If false, the setting is
825                                 applied to all configured commands the
826                                 same way. Defaults to
827                                 false.</para></listitem>
828                         </varlistentry>
829
830                         <varlistentry>
831                                 <term><varname>NonBlocking=</varname></term>
832                                 <listitem><para>Set O_NONBLOCK flag
833                                 for all file descriptors passed via
834                                 socket-based activation. If true, all
835                                 file descriptors >= 3 (i.e. all except
836                                 STDIN/STDOUT/STDERR) will have
837                                 the O_NONBLOCK flag set and hence are in
838                                 non-blocking mode. This option is only
839                                 useful in conjunction with a socket
840                                 unit, as described in
841                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
842                                 to false.</para></listitem>
843                         </varlistentry>
844
845                         <varlistentry>
846                                 <term><varname>NotifyAccess=</varname></term>
847                                 <listitem><para>Controls access to the
848                                 service status notification socket, as
849                                 accessible via the
850                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
851                                 call. Takes one of
852                                 <option>none</option> (the default),
853                                 <option>main</option> or
854                                 <option>all</option>. If
855                                 <option>none</option>, no daemon status
856                                 updates are accepted from the service
857                                 processes, all status update messages
858                                 are ignored. If <option>main</option>,
859                                 only service updates sent from the
860                                 main process of the service are
861                                 accepted. If <option>all</option>, all
862                                 services updates from all members of
863                                 the service's control group are
864                                 accepted. This option should be set to
865                                 open access to the notification socket
866                                 when using
867                                 <varname>Type=notify</varname> or
868                                 <varname>WatchdogSec=</varname> (see
869                                 above). If those options are used but
870                                 <varname>NotifyAccess=</varname> is not
871                                 configured, it will be implicitly set
872                                 to
873                                 <option>main</option>.</para></listitem>
874                         </varlistentry>
875
876                         <varlistentry>
877                                 <term><varname>Sockets=</varname></term>
878                                 <listitem><para>Specifies the name of
879                                 the socket units this service shall
880                                 inherit the sockets from when the
881                                 service is started. Normally it
882                                 should not be necessary to use this
883                                 setting as all sockets whose unit
884                                 shares the same name as the service
885                                 (ignoring the different suffix of course)
886                                 are passed to the spawned
887                                 process.</para>
888
889                                 <para>Note that the same socket may be
890                                 passed to multiple processes at the
891                                 same time. Also note that a different
892                                 service may be activated on incoming
893                                 traffic than inherits the sockets. Or
894                                 in other words: the
895                                 <varname>Service=</varname> setting of
896                                 <filename>.socket</filename> units
897                                 does not have to match the inverse of
898                                 the <varname>Sockets=</varname>
899                                 setting of the
900                                 <filename>.service</filename> it
901                                 refers to.</para>
902
903                                 <para>This option may appear more than
904                                 once, in which case the list of socket
905                                 units is merged. If the empty string
906                                 is assigned to this option, the list of
907                                 sockets is reset, all prior uses of
908                                 this setting will have no
909                                 effect.</para></listitem>
910                         </varlistentry>
911
912                         <varlistentry>
913                                 <term><varname>StartLimitInterval=</varname></term>
914                                 <term><varname>StartLimitBurst=</varname></term>
915
916                                 <listitem><para>Configure service
917                                 start rate limiting. By default,
918                                 services which are started more often
919                                 than 5 times within 10s are not
920                                 permitted to start any more times
921                                 until the 10s interval ends. With
922                                 these two options, this rate limiting
923                                 may be modified. Use
924                                 <varname>StartLimitInterval=</varname>
925                                 to configure the checking interval (defaults to
926                                 <varname>DefaultStartLimitInterval=</varname> in
927                                 manager configuration file, set to 0 to disable
928                                 any kind of rate limiting). Use
929                                 <varname>StartLimitBurst=</varname> to
930                                 configure how many starts per interval
931                                 are allowed (defaults to
932                                 <varname>DefaultStartLimitBurst=</varname> in
933                                 manager configuration file). These
934                                 configuration options are particularly
935                                 useful in conjunction with
936                                 <varname>Restart=</varname>, however
937                                 apply to all kinds of starts
938                                 (including manual), not just those
939                                 triggered by the
940                                 <varname>Restart=</varname> logic.
941                                 Note that units which are configured
942                                 for <varname>Restart=</varname> and
943                                 which reach the start limit are not
944                                 attempted to be restarted anymore,
945                                 however they may still be restarted
946                                 manually at a later point from which
947                                 point on the restart logic is again
948                                 activated. Note that
949                                 <command>systemctl
950                                 reset-failed</command> will cause the
951                                 restart rate counter for a service to
952                                 be flushed, which is useful if the
953                                 administrator wants to manually start
954                                 a service and the start limit
955                                 interferes with
956                                 that.</para></listitem>
957                         </varlistentry>
958
959                         <varlistentry>
960                                 <term><varname>StartLimitAction=</varname></term>
961
962                                 <listitem><para>Configure the action
963                                 to take if the rate limit configured
964                                 with
965                                 <varname>StartLimitInterval=</varname>
966                                 and
967                                 <varname>StartLimitBurst=</varname> is
968                                 hit. Takes one of
969                                 <option>none</option>,
970                                 <option>reboot</option>,
971                                 <option>reboot-force</option> or
972                                 <option>reboot-immediate</option>. If
973                                 <option>none</option> is set,
974                                 hitting the rate limit will trigger no
975                                 action besides that the start will not
976                                 be
977                                 permitted. <option>reboot</option>
978                                 causes a reboot following the normal
979                                 shutdown procedure (i.e. equivalent to
980                                 <command>systemctl reboot</command>),
981                                 <option>reboot-force</option> causes
982                                 an forced reboot which will terminate
983                                 all processes forcibly but should
984                                 cause no dirty file systems on reboot
985                                 (i.e. equivalent to <command>systemctl
986                                 reboot -f</command>) and
987                                 <option>reboot-immediate</option>
988                                 causes immediate execution of the
989                                 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
990                                 system call, which might result in
991                                 data loss.  Defaults to
992                                 <option>none</option>.</para></listitem>
993                         </varlistentry>
994
995                 </variablelist>
996
997                 <para>Check
998                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
999                 and
1000                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1001                 for more settings.</para>
1002
1003         </refsect1>
1004
1005         <refsect1>
1006                 <title>Compatibility Options</title>
1007
1008                 <para>The following options are also available in the
1009                 <literal>[Service]</literal> section, but exist purely
1010                 for compatibility reasons and should not be used in
1011                 newly written service files.</para>
1012
1013                 <variablelist class='unit-directives'>
1014                         <varlistentry>
1015                                 <term><varname>SysVStartPriority=</varname></term>
1016                                 <listitem><para>Set the SysV start
1017                                 priority to use to order this service
1018                                 in relation to SysV services lacking
1019                                 LSB headers. This option is only
1020                                 necessary to fix ordering in relation
1021                                 to legacy SysV services, that have no
1022                                 ordering information encoded in the
1023                                 script headers. As such it should only
1024                                 be used as temporary compatibility
1025                                 option, and not be used in new unit
1026                                 files. Almost always it is a better
1027                                 choice to add explicit ordering
1028                                 directives via
1029                                 <varname>After=</varname> or
1030                                 <varname>Before=</varname>,
1031                                 instead. For more details see
1032                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
1033                                 used, pass an integer value in the
1034                                 range 0-99.</para></listitem>
1035                         </varlistentry>
1036
1037                 </variablelist>
1038         </refsect1>
1039
1040         <refsect1>
1041                   <title>See Also</title>
1042                   <para>
1043                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1044                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1045                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1046                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1047                           <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1048                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1049                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
1050                   </para>
1051         </refsect1>
1052
1053 </refentry>