man/systemd.service.xml

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   7   This file is part of systemd.
   8
   9   Copyright 2010 Lennart Poettering
  10
  11   systemd is free software; you can redistribute it and/or modify it
  12   under the terms of the GNU Lesser General Public License as published by
  13   the Free Software Foundation; either version 2.1 of the License, or
  14   (at your option) any later version.
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  19   Lesser General Public License for more details.
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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. The first
 309                                 argument must be an absolute path
 310                                 name.</para>
 311
 312                                 <para>When <varname>Type</varname> is
 313                                 not <option>oneshot</option>, only one
 314                                 command may be given. When
 315                                 <varname>Type=oneshot</varname> is
 316                                 used, more than one command may be
 317                                 specified. Multiple command lines may
 318                                 be concatenated in a single directive,
 319                                 by separating them with semicolons
 320                                 (these semicolons must be passed as
 321                                 separate words). Alternatively, this
 322                                 directive may be specified more than
 323                                 once with the same effect. However,
 324                                 the latter syntax is not recommended
 325                                 for compatibility with parsers
 326                                 suitable for XDG
 327                                 <filename>.desktop</filename> files.
 328                                 Lone semicolons may be escaped as
 329                                 <literal>\;</literal>. If the empty
 330                                 string is assigned to this option, the
 331                                 list of commands to start is reset,
 332                                 prior assignments of this option will
 333                                 have no effect.</para>
 334
 335                                 <para>If more than one command is
 336                                 specified, the commands are invoked
 337                                 one by one sequentially in the order
 338                                 they appear in the unit file. If one
 339                                 of the commands fails (and is not
 340                                 prefixed with <literal>-</literal>),
 341                                 other lines are not executed and the
 342                                 unit is considered failed.</para>
 343
 344                                 <para>Unless
 345                                 <varname>Type=forking</varname> is
 346                                 set, the process started via this
 347                                 command line will be considered the
 348                                 main process of the daemon.</para>
 349
 350                                 <para>The command line accepts
 351                                 <literal>%</literal> specifiers as
 352                                 described in
 353                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Note
 354                                 that the first argument of the command
 355                                 line (i.e. the program to execute) may
 356                                 not include specifiers.</para>
 357
 358                                 <para>Basic environment variable
 359                                 substitution is supported. Use
 360                                 <literal>${FOO}</literal> as part of a
 361                                 word, or as a word of its own on the
 362                                 command line, in which case it will be
 363                                 replaced by the value of the
 364                                 environment variable including all
 365                                 whitespace it contains, resulting in a
 366                                 single argument.  Use
 367                                 <literal>$FOO</literal> as a separate
 368                                 word on the command line, in which
 369                                 case it will be replaced by the value
 370                                 of the environment variable split up
 371                                 at whitespace, resulting in zero or
 372                                 more arguments. To pass a literal dollar sign,
 373                                 use <literal>$$</literal>. Note that the first
 374                                 argument (i.e. the program to execute)
 375                                 may not be a variable, since it must
 376                                 be a literal and absolute path
 377                                 name.</para>
 378
 379                                 <para>Optionally, if the absolute file
 380                                 name is prefixed with
 381                                 <literal>@</literal>, the second token
 382                                 will be passed as
 383                                 <literal>argv[0]</literal> to the
 384                                 executed process, followed by the
 385                                 further arguments specified. If the
 386                                 absolute filename is prefixed with
 387                                 <literal>-</literal>, an exit code of
 388                                 the command normally considered a
 389                                 failure (i.e. non-zero exit status or
 390                                 abnormal exit due to signal) is ignored
 391                                 and considered success. If both
 392                                 <literal>-</literal> and
 393                                 <literal>@</literal> are used, they
 394                                 can appear in either order.</para>
 395
 396                                 <para>Note that this setting does not
 397                                 directly support shell command
 398                                 lines. If shell command lines are to
 399                                 be used, they need to be passed
 400                                 explicitly to a shell implementation
 401                                 of some kind. Example:</para>
 402                                 <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'
 403                                 </programlisting>
 404
 405                                 <para>For services run by a user
 406                                 instance of systemd the special
 407                                 environment variable
 408                                 <varname>$MANAGERPID</varname> is set
 409                                 to the PID of the systemd
 410                                 instance.</para>
 411                                 </listitem>
 412                         </varlistentry>
 413
 414                         <varlistentry>
 415                                 <term><varname>ExecStartPre=</varname></term>
 416                                 <term><varname>ExecStartPost=</varname></term>
 417                                 <listitem><para>Additional commands
 418                                 that are executed before or after
 419                                 the command in
 420                                 <varname>ExecStart=</varname>, respectively.
 421                                 Syntax is the same as for
 422                                 <varname>ExecStart=</varname>, except
 423                                 that multiple command lines are allowed
 424                                 and the commands are executed one
 425                                 after the other, serially.</para>
 426
 427                                 <para>If any of those commands (not
 428                                 prefixed with <literal>-</literal>)
 429                                 fail, the rest are not executed and
 430                                 the unit is considered failed.</para>
 431                                 </listitem>
 432                         </varlistentry>
 433
 434                         <varlistentry>
 435                                 <term><varname>ExecReload=</varname></term>
 436                                 <listitem><para>Commands to execute to
 437                                 trigger a configuration reload in the
 438                                 service. This argument takes multiple
 439                                 command lines, following the same
 440                                 scheme as described for
 441                                 <varname>ExecStart=</varname>
 442                                 above. Use of this setting is
 443                                 optional. Specifier and environment
 444                                 variable substitution is supported
 445                                 here following the same scheme as for
 446                                 <varname>ExecStart=</varname>.</para>
 447
 448                                 <para>One additional special
 449                                 environment variables is set: if known
 450                                 <varname>$MAINPID</varname> is set to
 451                                 the main process of the daemon, and
 452                                 may be used for command lines like the
 453                                 following:</para>
 454
 455                                 <programlisting>/bin/kill -HUP $MAINPID</programlisting>
 456                                 </listitem>
 457                         </varlistentry>
 458
 459                         <varlistentry>
 460                                 <term><varname>ExecStop=</varname></term>
 461                                 <listitem><para>Commands to execute to
 462                                 stop the service started via
 463                                 <varname>ExecStart=</varname>. This
 464                                 argument takes multiple command lines,
 465                                 following the same scheme as described
 466                                 for <varname>ExecStart=</varname>
 467                                 above. Use of this setting is
 468                                 optional. All processes remaining for
 469                                 a service after the commands
 470                                 configured in this option are run are
 471                                 terminated according to the
 472                                 <varname>KillMode=</varname> setting
 473                                 (see
 474                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
 475                                 this option is not specified, the
 476                                 process is terminated right-away when
 477                                 service stop is requested. Specifier
 478                                 and environment variable substitution
 479                                 is supported (including
 480                                 <varname>$MAINPID</varname>, see
 481                                 above).</para></listitem>
 482                         </varlistentry>
 483
 484                         <varlistentry>
 485                                 <term><varname>ExecStopPost=</varname></term>
 486                                 <listitem><para>Additional commands
 487                                 that are executed after the service
 488                                 was stopped. This includes cases where
 489                                 the commands configured in
 490                                 <varname>ExecStop=</varname> were used,
 491                                 where the service does not have any
 492                                 <varname>ExecStop=</varname> defined, or
 493                                 where the service exited unexpectedly. This
 494                                 argument takes multiple command lines,
 495                                 following the same scheme as described
 496                                 for <varname>ExecStart</varname>. Use
 497                                 of these settings is
 498                                 optional. Specifier and environment
 499                                 variable substitution is
 500                                 supported.</para></listitem>
 501                         </varlistentry>
 502
 503                         <varlistentry>
 504                                 <term><varname>RestartSec=</varname></term>
 505                                 <listitem><para>Configures the time to
 506                                 sleep before restarting a service (as
 507                                 configured with
 508                                 <varname>Restart=</varname>). Takes a
 509                                 unit-less value in seconds, or a time
 510                                 span value such as "5min
 511                                 20s". Defaults to
 512                                 100ms.</para></listitem>
 513                         </varlistentry>
 514
 515                         <varlistentry>
 516                                 <term><varname>TimeoutStartSec=</varname></term>
 517                                 <listitem><para>Configures the time to
 518                                 wait for start-up. If a
 519                                 daemon service does not signal
 520                                 start-up completion within the
 521                                 configured time, the service will be
 522                                 considered failed and be shut down
 523                                 again.
 524                                 Takes a unit-less value in seconds, or a
 525                                 time span value such as "5min
 526                                 20s". Pass 0 to disable the timeout
 527                                 logic. Defaults to <varname>TimeoutStartSec=</varname> from the
 528                                 manager configuration file, except when
 529                                 <varname>Type=oneshot</varname> is
 530                                 used, in which case the timeout
 531                                 is disabled by default.
 532                                 </para></listitem>
 533                         </varlistentry>
 534
 535                         <varlistentry>
 536                                 <term><varname>TimeoutStopSec=</varname></term>
 537                                 <listitem><para>Configures the time to
 538                                 wait for stop. If a service is asked
 539                                 to stop but does not terminate in the
 540                                 specified time, it will be terminated
 541                                 forcibly via <constant>SIGTERM</constant>, and after
 542                                 another delay of this time with
 543                                 <constant>SIGKILL</constant> (See
 544                                 <varname>KillMode=</varname>
 545                                 in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
 546                                 Takes a unit-less value in seconds, or a
 547                                 time span value such as "5min
 548                                 20s". Pass 0 to disable the timeout
 549                                 logic. Defaults to <varname>TimeoutStartSec=</varname> from the
 550                                 manager configuration file.
 551                                 </para></listitem>
 552                         </varlistentry>
 553
 554                         <varlistentry>
 555                                 <term><varname>TimeoutSec=</varname></term>
 556                                 <listitem><para>A shorthand for configuring
 557                                 both <varname>TimeoutStartSec=</varname>
 558                                 and <varname>TimeoutStopSec=</varname>
 559                                 to the specified value.
 560                                 </para></listitem>
 561                         </varlistentry>
 562
 563                         <varlistentry>
 564                                 <term><varname>WatchdogSec=</varname></term>
 565                                 <listitem><para>Configures the
 566                                 watchdog timeout for a service. The
 567                                 watchdog is activated when the start-up is
 568                                 completed. The service must call
 569                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 570                                 regularly with "WATCHDOG=1" (i.e. the
 571                                 "keep-alive ping"). If the time
 572                                 between two such calls is larger than
 573                                 the configured time, then the service
 574                                 is placed in a failure state. By
 575                                 setting <varname>Restart=</varname> to
 576                                 <option>on-failure</option> or
 577                                 <option>always</option>, the service
 578                                 will be automatically restarted. The
 579                                 time configured here will be passed to
 580                                 the executed service process in the
 581                                 <varname>WATCHDOG_USEC=</varname>
 582                                 environment variable. This allows
 583                                 daemons to automatically enable the
 584                                 keep-alive pinging logic if watchdog
 585                                 support is enabled for the service. If
 586                                 this option is used,
 587                                 <varname>NotifyAccess=</varname> (see
 588                                 below) should be set to open access to
 589                                 the notification socket provided by
 590                                 systemd. If
 591                                 <varname>NotifyAccess=</varname> is
 592                                 not set, it will be implicitly set to
 593                                 <option>main</option>. Defaults to 0,
 594                                 which disables this
 595                                 feature.</para></listitem>
 596                         </varlistentry>
 597
 598                         <varlistentry>
 599                                 <term><varname>Restart=</varname></term>
 600                                 <listitem><para>Configures whether the
 601                                 service shall be restarted when the
 602                                 service process exits, is killed,
 603                                 or a timeout is reached. The service
 604                                 process may be the main service
 605                                 process, but also one of the processes
 606                                 specified with
 607                                 <varname>ExecStartPre=</varname>,
 608                                 <varname>ExecStartPost=</varname>,
 609                                 <varname>ExecStopPre=</varname>,
 610                                 <varname>ExecStopPost=</varname>, or
 611                                 <varname>ExecReload=</varname>.
 612                                 When the death of the process is a
 613                                 result of systemd operation (e.g. service
 614                                 stop or restart), the service will not be
 615                                 restarted. Timeouts include missing
 616                                 the watchdog "keep-alive ping"
 617                                 deadline and a service start, reload,
 618                                 and stop operation timeouts.</para>
 619
 620                                 <para>Takes one of
 621                                 <option>no</option>,
 622                                 <option>on-success</option>,
 623                                 <option>on-failure</option>,
 624                                 <option>on-watchdog</option>,
 625                                 <option>on-abort</option>, or
 626                                 <option>always</option>. If set to
 627                                 <option>no</option> (the default), the
 628                                 service will not be restarted. If set to
 629                                 <option>on-success</option>, it will be
 630                                 restarted only when the service process
 631                                 exits cleanly.
 632                                 In this context, a clean exit means
 633                                 an exit code of 0, or one of the signals
 634                                 <constant>SIGHUP</constant>, <constant>SIGINT</constant>, <constant>SIGTERM</constant>, or <constant>SIGPIPE</constant>, and
 635                                 additionally, exit statuses and signals
 636                                 specified in <varname>SuccessExitStatus=</varname>.
 637                                 If set to <option>on-failure</option>,
 638                                 the service will be restarted when the
 639                                 process exits with an nonzero exit code,
 640                                 is terminated by a signal (including on
 641                                 core dump), when an operation (such as
 642                                 service reload) times out, and when the
 643                                 configured watchdog timeout is triggered.
 644                                 If set to
 645                                 <option>on-abort</option>, the service
 646                                 will be restarted only if the service
 647                                 process exits due to an uncaught
 648                                 signal not specified as a clean exit
 649                                 status.
 650                                 If set to
 651                                 <option>on-watchdog</option>, the service
 652                                 will be restarted only if the watchdog
 653                                 timeout for the service expires.
 654                                 If set to
 655                                 <option>always</option>, the service
 656                                 will be restarted regardless whether
 657                                 it exited cleanly or not, got
 658                                 terminated abnormally by a signal or
 659                                 hit a timeout.</para>
 660
 661                                 <para>In addition to the above settings,
 662                                 the service will not be restarted if the
 663                                 exit code or signal is specified in
 664                                 <varname>RestartPreventExitStatus=</varname>
 665                                 (see below).</para></listitem>
 666                         </varlistentry>
 667
 668                         <varlistentry>
 669                                 <term><varname>SuccessExitStatus=</varname></term>
 670                                 <listitem><para>Takes a list of exit
 671                                 status definitions that when returned
 672                                 by the main service process will be
 673                                 considered successful termination, in
 674                                 addition to the normal successful exit
 675                                 code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
 676                                 <constant>SIGTERM</constant> and <constant>SIGPIPE</constant>. Exit status
 677                                 definitions can either be numeric exit
 678                                 codes or termination signal names,
 679                                 separated by spaces. Example:
 680                                 <literal>SuccessExitStatus=1 2 8
 681                                 <constant>SIGKILL</constant></literal>, ensures that exit
 682                                 codes 1, 2, 8 and the termination
 683                                 signal <constant>SIGKILL</constant> are considered clean
 684                                 service terminations. This option may
 685                                 appear more than once in which case
 686                                 the list of successful exit statuses
 687                                 is merged. If the empty string is
 688                                 assigned to this option, the list is
 689                                 reset, all prior assignments of this
 690                                 option will have no
 691                                 effect.</para></listitem>
 692                         </varlistentry>
 693
 694                         <varlistentry>
 695                                 <term><varname>RestartPreventExitStatus=</varname></term>
 696                                 <listitem><para>Takes a list of exit
 697                                 status definitions that when returned
 698                                 by the main service process will
 699                                 prevent automatic service restarts
 700                                 regardless of the restart setting
 701                                 configured with
 702                                 <varname>Restart=</varname>. Exit
 703                                 status definitions can either be
 704                                 numeric exit codes or termination
 705                                 signal names, and are separated by
 706                                 spaces. Defaults to the empty list, so
 707                                 that by default no exit status is
 708                                 excluded from the configured restart
 709                                 logic. Example:
 710                                 <literal>RestartPreventExitStatus=1 6
 711                                 SIGABRT</literal>, ensures that exit
 712                                 codes 1 and 6 and the termination
 713                                 signal SIGABRT will not result in
 714                                 automatic service restarting. This
 715                                 option may appear more than once in
 716                                 which case the list of restart preventing
 717                                 statuses is merged. If the empty
 718                                 string is assigned to this option, the
 719                                 list is reset, all prior assignments
 720                                 of this option will have no
 721                                 effect.</para></listitem>
 722                         </varlistentry>
 723
 724                         <varlistentry>
 725                                 <term><varname>PermissionsStartOnly=</varname></term>
 726                                 <listitem><para>Takes a boolean
 727                                 argument. If true, the permission
 728                                 related execution options as
 729                                 configured with
 730                                 <varname>User=</varname> and similar
 731                                 options (see
 732                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 733                                 for more information) are only applied
 734                                 to the process started with
 735                                 <varname>ExecStart=</varname>, and not
 736                                 to the various other
 737                                 <varname>ExecStartPre=</varname>,
 738                                 <varname>ExecStartPost=</varname>,
 739                                 <varname>ExecReload=</varname>,
 740                                 <varname>ExecStop=</varname>,
 741                                 <varname>ExecStopPost=</varname>
 742                                 commands. If false, the setting is
 743                                 applied to all configured commands the
 744                                 same way. Defaults to
 745                                 false.</para></listitem>
 746                         </varlistentry>
 747
 748                         <varlistentry>
 749                                 <term><varname>RootDirectoryStartOnly=</varname></term>
 750                                 <listitem><para>Takes a boolean
 751                                 argument. If true, the root directory
 752                                 as configured with the
 753                                 <varname>RootDirectory=</varname>
 754                                 option (see
 755                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 756                                 for more information) is only applied
 757                                 to the process started with
 758                                 <varname>ExecStart=</varname>, and not
 759                                 to the various other
 760                                 <varname>ExecStartPre=</varname>,
 761                                 <varname>ExecStartPost=</varname>,
 762                                 <varname>ExecReload=</varname>,
 763                                 <varname>ExecStop=</varname>,
 764                                 <varname>ExecStopPost=</varname>
 765                                 commands. If false, the setting is
 766                                 applied to all configured commands the
 767                                 same way. Defaults to
 768                                 false.</para></listitem>
 769                         </varlistentry>
 770
 771                         <varlistentry>
 772                                 <term><varname>NonBlocking=</varname></term>
 773                                 <listitem><para>Set O_NONBLOCK flag
 774                                 for all file descriptors passed via
 775                                 socket-based activation. If true, all
 776                                 file descriptors >= 3 (i.e. all except
 777                                 STDIN/STDOUT/STDERR) will have
 778                                 the O_NONBLOCK flag set and hence are in
 779                                 non-blocking mode. This option is only
 780                                 useful in conjunction with a socket
 781                                 unit, as described in
 782                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
 783                                 to false.</para></listitem>
 784                         </varlistentry>
 785
 786                         <varlistentry>
 787                                 <term><varname>NotifyAccess=</varname></term>
 788                                 <listitem><para>Controls access to the
 789                                 service status notification socket, as
 790                                 accessible via the
 791                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 792                                 call. Takes one of
 793                                 <option>none</option> (the default),
 794                                 <option>main</option> or
 795                                 <option>all</option>. If
 796                                 <option>none</option>, no daemon status
 797                                 updates are accepted from the service
 798                                 processes, all status update messages
 799                                 are ignored. If <option>main</option>,
 800                                 only service updates sent from the
 801                                 main process of the service are
 802                                 accepted. If <option>all</option>, all
 803                                 services updates from all members of
 804                                 the service's control group are
 805                                 accepted. This option should be set to
 806                                 open access to the notification socket
 807                                 when using
 808                                 <varname>Type=notify</varname> or
 809                                 <varname>WatchdogSec=</varname> (see
 810                                 above). If those options are used but
 811                                 <varname>NotifyAccess=</varname> is not
 812                                 configured, it will be implicitly set
 813                                 to
 814                                 <option>main</option>.</para></listitem>
 815                         </varlistentry>
 816
 817                         <varlistentry>
 818                                 <term><varname>Sockets=</varname></term>
 819                                 <listitem><para>Specifies the name of
 820                                 the socket units this service shall
 821                                 inherit the sockets from when the
 822                                 service is started. Normally it
 823                                 should not be necessary to use this
 824                                 setting as all sockets whose unit
 825                                 shares the same name as the service
 826                                 (ignoring the different suffix of course)
 827                                 are passed to the spawned
 828                                 process.</para>
 829
 830                                 <para>Note that the same socket may be
 831                                 passed to multiple processes at the
 832                                 same time. Also note that a different
 833                                 service may be activated on incoming
 834                                 traffic than inherits the sockets. Or
 835                                 in other words: the
 836                                 <varname>Service=</varname> setting of
 837                                 <filename>.socket</filename> units
 838                                 does not have to match the inverse of
 839                                 the <varname>Sockets=</varname>
 840                                 setting of the
 841                                 <filename>.service</filename> it
 842                                 refers to.</para>
 843
 844                                 <para>This option may appear more than
 845                                 once, in which case the list of socket
 846                                 units is merged. If the empty string
 847                                 is assigned to this option, the list of
 848                                 sockets is reset, all prior uses of
 849                                 this setting will have no
 850                                 effect.</para></listitem>
 851                         </varlistentry>
 852
 853                         <varlistentry>
 854                                 <term><varname>StartLimitInterval=</varname></term>
 855                                 <term><varname>StartLimitBurst=</varname></term>
 856
 857                                 <listitem><para>Configure service
 858                                 start rate limiting. By default,
 859                                 services which are started more often
 860                                 than 5 times within 10s are not
 861                                 permitted to start any more times
 862                                 until the 10s interval ends. With
 863                                 these two options, this rate limiting
 864                                 may be modified. Use
 865                                 <varname>StartLimitInterval=</varname>
 866                                 to configure the checking interval (defaults to
 867                                 <varname>DefaultStartLimitInterval=</varname> in
 868                                 manager configuration file, set to 0 to disable
 869                                 any kind of rate limiting). Use
 870                                 <varname>StartLimitBurst=</varname> to
 871                                 configure how many starts per interval
 872                                 are allowed (defaults to
 873                                 <varname>DefaultStartLimitBurst=</varname> in
 874                                 manager configuration file). These
 875                                 configuration options are particularly
 876                                 useful in conjunction with
 877                                 <varname>Restart=</varname>, however
 878                                 apply to all kinds of starts
 879                                 (including manual), not just those
 880                                 triggered by the
 881                                 <varname>Restart=</varname> logic.
 882                                 Note that units which are configured
 883                                 for <varname>Restart=</varname> and
 884                                 which reach the start limit are not
 885                                 attempted to be restarted anymore,
 886                                 however they may still be restarted
 887                                 manually at a later point from which
 888                                 point on the restart logic is again
 889                                 activated. Note that
 890                                 <command>systemctl
 891                                 reset-failed</command> will cause the
 892                                 restart rate counter for a service to
 893                                 be flushed, which is useful if the
 894                                 administrator wants to manually start
 895                                 a service and the start limit
 896                                 interferes with
 897                                 that.</para></listitem>
 898                         </varlistentry>
 899
 900                         <varlistentry>
 901                                 <term><varname>StartLimitAction=</varname></term>
 902
 903                                 <listitem><para>Configure the action
 904                                 to take if the rate limit configured
 905                                 with
 906                                 <varname>StartLimitInterval=</varname>
 907                                 and
 908                                 <varname>StartLimitBurst=</varname> is
 909                                 hit. Takes one of
 910                                 <option>none</option>,
 911                                 <option>reboot</option>,
 912                                 <option>reboot-force</option> or
 913                                 <option>reboot-immediate</option>. If
 914                                 <option>none</option> is set,
 915                                 hitting the rate limit will trigger no
 916                                 action besides that the start will not
 917                                 be
 918                                 permitted. <option>reboot</option>
 919                                 causes a reboot following the normal
 920                                 shutdown procedure (i.e. equivalent to
 921                                 <command>systemctl reboot</command>),
 922                                 <option>reboot-force</option> causes
 923                                 an forced reboot which will terminate
 924                                 all processes forcibly but should
 925                                 cause no dirty file systems on reboot
 926                                 (i.e. equivalent to <command>systemctl
 927                                 reboot -f</command>) and
 928                                 <option>reboot-immediate</option>
 929                                 causes immediate execution of the
 930                                 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 931                                 system call, which might result in
 932                                 data loss.  Defaults to
 933                                 <option>none</option>.</para></listitem>
 934                         </varlistentry>
 935
 936                 </variablelist>
 937
 938                 <para>Check
 939                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 940                 and
 941                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 942                 for more settings.</para>
 943
 944         </refsect1>
 945
 946         <refsect1>
 947                 <title>Compatibility Options</title>
 948
 949                 <para>The following options are also available in the
 950                 <literal>[Service]</literal> section, but exist purely
 951                 for compatibility reasons and should not be used in
 952                 newly written service files.</para>
 953
 954                 <variablelist class='unit-directives'>
 955                         <varlistentry>
 956                                 <term><varname>SysVStartPriority=</varname></term>
 957                                 <listitem><para>Set the SysV start
 958                                 priority to use to order this service
 959                                 in relation to SysV services lacking
 960                                 LSB headers. This option is only
 961                                 necessary to fix ordering in relation
 962                                 to legacy SysV services, that have no
 963                                 ordering information encoded in the
 964                                 script headers. As such it should only
 965                                 be used as temporary compatibility
 966                                 option, and not be used in new unit
 967                                 files. Almost always it is a better
 968                                 choice to add explicit ordering
 969                                 directives via
 970                                 <varname>After=</varname> or
 971                                 <varname>Before=</varname>,
 972                                 instead. For more details see
 973                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
 974                                 used, pass an integer value in the
 975                                 range 0-99.</para></listitem>
 976                         </varlistentry>
 977
 978                 </variablelist>
 979         </refsect1>
 980
 981         <refsect1>
 982                   <title>See Also</title>
 983                   <para>
 984                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 985                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 986                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 987                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 988                           <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 989                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 990                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 991                   </para>
 992         </refsect1>
 993
 994 </refentry>