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>systemd service configuration files</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>systemd.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.</para>
  76
  77                 <para>Unless <varname>DefaultDependencies=</varname>
  78                 is set to <option>false</option>, service units will
  79                 implicitly have dependencies of type
  80                 <varname>Requires=</varname> and
  81                 <varname>After=</varname> on
  82                 <filename>basic.target</filename> as well as
  83                 dependencies of type <varname>Conflicts=</varname> and
  84                 <varname>Before=</varname> on
  85                 <filename>shutdown.target</filename>. These ensure
  86                 that normal service units pull in basic system
  87                 initialization, and are terminated cleanly prior to
  88                 system shutdown. Only services involved with early
  89                 boot or late system shutdown should disable this
  90                 option.</para>
  91
  92                 <para>If a service is requested under a certain name
  93                 but no unit configuration file is found, systemd looks
  94                 for a SysV init script by the same name (with the
  95                 <filename>.service</filename> suffix removed) and
  96                 dynamically creates a service unit from that
  97                 script. This is useful for compatibility with
  98                 SysV. Note that this compatibility is quite
  99                 comprehensive but not 100%. For details about the
 100                 incomptibilities see the <ulink
 101                 url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
 102                 with SysV</ulink> document.
 103                 </para>
 104         </refsect1>
 105
 106         <refsect1>
 107                 <title>Options</title>
 108
 109                 <para>Service files must include a
 110                 <literal>[Service]</literal> section, which carries
 111                 information about the service and the process it
 112                 supervises. A number of options that may be used in
 113                 this section are shared with other unit types. These
 114                 options are documented in
 115                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 116                 options specific to the <literal>[Service]</literal>
 117                 section of service units are the following:</para>
 118
 119                 <variablelist>
 120                         <varlistentry>
 121                                 <term><varname>Type=</varname></term>
 122
 123                                 <listitem><para>Configures the process
 124                                 start-up type for this service
 125                                 unit. One of <option>simple</option>,
 126                                 <option>forking</option>,
 127                                 <option>oneshot</option>,
 128                                 <option>dbus</option>,
 129                                 <option>notify</option> or
 130                                 <option>idle</option>.</para>
 131
 132                                 <para>If set to
 133                                 <option>simple</option> (the default
 134                                 value if <varname>BusName=</varname>
 135                                 is not specified) it is expected that
 136                                 the process configured with
 137                                 <varname>ExecStart=</varname> is the
 138                                 main process of the service. In this
 139                                 mode, if the process offers
 140                                 functionality to other processes on
 141                                 the system its communication channels
 142                                 should be installed before the daemon
 143                                 is started up (e.g. sockets set up by
 144                                 systemd, via socket activation), as
 145                                 systemd will immediately proceed
 146                                 starting follow-up units.</para>
 147
 148                                 <para>If set to
 149                                 <option>forking</option> it is
 150                                 expected that the process configured
 151                                 with <varname>ExecStart=</varname>
 152                                 will call <function>fork()</function>
 153                                 as part of its start-up. The parent process is
 154                                 expected to exit when start-up is
 155                                 complete and all communication
 156                                 channels set up. The child continues
 157                                 to run as the main daemon
 158                                 process. This is the behaviour of
 159                                 traditional UNIX daemons. If this
 160                                 setting is used, it is recommended to
 161                                 also use the
 162                                 <varname>PIDFile=</varname> option, so
 163                                 that systemd can identify the main
 164                                 process of the daemon. systemd will
 165                                 proceed starting follow-up units as
 166                                 soon as the parent process
 167                                 exits.</para>
 168
 169                                 <para>Behaviour of
 170                                 <option>oneshot</option> is similar
 171                                 to <option>simple</option>, however
 172                                 it is expected that the process has to
 173                                 exit before systemd starts follow-up
 174                                 units. <varname>RemainAfterExit=</varname>
 175                                 is particularly useful for this type
 176                                 of service.</para>
 177
 178                                 <para>Behaviour of
 179                                 <option>dbus</option> is similar to
 180                                 <option>simple</option>, however it is
 181                                 expected that the daemon acquires a
 182                                 name on the D-Bus bus, as configured
 183                                 by
 184                                 <varname>BusName=</varname>. systemd
 185                                 will proceed starting follow-up units
 186                                 after the D-Bus bus name has been
 187                                 acquired. Service units with this
 188                                 option configured implicitly gain
 189                                 dependencies on the
 190                                 <filename>dbus.socket</filename>
 191                                 unit. This type is the default if
 192                                 <varname>BusName=</varname> is
 193                                 specified.</para>
 194
 195                                 <para>Behaviour of
 196                                 <option>notify</option> is similar to
 197                                 <option>simple</option>, however it is
 198                                 expected that the daemon sends a
 199                                 notification message via
 200                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 201                                 or an equivalent call when it finished
 202                                 starting up. systemd will proceed
 203                                 starting follow-up units after this
 204                                 notification message has been sent. If
 205                                 this option is used
 206                                 <varname>NotifyAccess=</varname> (see
 207                                 below) should be set to open access to
 208                                 the notification socket provided by
 209                                 systemd. If
 210                                 <varname>NotifyAccess=</varname> is
 211                                 not set, it will be implicitly set to
 212                                 <option>main</option>.</para>
 213
 214                                 <para>Behaviour of
 215                                 <option>idle</option> is very similar
 216                                 to <option>simple</option>, however
 217                                 actual execution of a the service
 218                                 binary is delayed until all jobs are
 219                                 dispatched. This may be used to avoid
 220                                 interleaving of output of shell
 221                                 services with the status output on the
 222                                 console.</para>
 223                                 </listitem>
 224                         </varlistentry>
 225
 226                         <varlistentry>
 227                                 <term><varname>RemainAfterExit=</varname></term>
 228
 229                                 <listitem><para>Takes a boolean value
 230                                 that specifies whether the service
 231                                 shall be considered active even when
 232                                 all its processes exited. Defaults to
 233                                 <option>no</option>.</para>
 234                                 </listitem>
 235                         </varlistentry>
 236
 237                         <varlistentry>
 238                                 <term><varname>GuessMainPID=</varname></term>
 239
 240                                 <listitem><para>Takes a boolean value
 241                                 that specifies whether systemd should
 242                                 try to guess the main PID of a service
 243                                 should if it cannot be determined
 244                                 reliably. This option is ignored
 245                                 unless <option>Type=forking</option>
 246                                 is set and <option>PIDFile=</option>
 247                                 is unset because for the other types
 248                                 or with an explicitly configured PID
 249                                 file the main PID is always known. The
 250                                 guessing algorithm might come to
 251                                 incorrect conclusions if a daemon
 252                                 consists of more than one process. If
 253                                 the main PID cannot be determined
 254                                 failure detection and automatic
 255                                 restarting of a service will not work
 256                                 reliably. Defaults to
 257                                 <option>yes</option>.</para>
 258                                 </listitem>
 259                         </varlistentry>
 260
 261                         <varlistentry>
 262                                 <term><varname>PIDFile=</varname></term>
 263
 264                                 <listitem><para>Takes an absolute file
 265                                 name pointing to the PID file of this
 266                                 daemon. Use of this option is
 267                                 recommended for services where
 268                                 <varname>Type=</varname> is set to
 269                                 <option>forking</option>. systemd will
 270                                 read the PID of the main process of
 271                                 the daemon after start-up of the
 272                                 service. systemd will not write to the
 273                                 file configured here.</para>
 274                                 </listitem>
 275                         </varlistentry>
 276
 277                         <varlistentry>
 278                                 <term><varname>BusName=</varname></term>
 279
 280                                 <listitem><para>Takes a D-Bus bus
 281                                 name, where this service is reachable
 282                                 as. This option is mandatory for
 283                                 services where
 284                                 <varname>Type=</varname> is set to
 285                                 <option>dbus</option>, but its use
 286                                 is otherwise recommended as well if
 287                                 the process takes a name on the D-Bus
 288                                 bus.</para>
 289                                 </listitem>
 290                         </varlistentry>
 291
 292                         <varlistentry>
 293                                 <term><varname>ExecStart=</varname></term>
 294                                 <listitem><para>Takes a command line
 295                                 that is executed when this service
 296                                 shall be started up. The first token
 297                                 of the command line must be an
 298                                 absolute file name, then followed by
 299                                 arguments for the process. It is
 300                                 mandatory to set this option for all
 301                                 services. This option may not be
 302                                 specified more than once, except when
 303                                 <varname>Type=oneshot</varname> is
 304                                 used in which case more than one
 305                                 <varname>ExecStart=</varname> line is
 306                                 accepted which are then invoked one by
 307                                 one, sequentially in the order they
 308                                 appear in the unit file.</para>
 309
 310                                 <para>Optionally, if the absolute file
 311                                 name is prefixed with
 312                                 <literal>@</literal>, the second token
 313                                 will be passed as
 314                                 <literal>argv[0]</literal> to the
 315                                 executed process, followed by the
 316                                 further arguments specified. If the
 317                                 first token is prefixed with
 318                                 <literal>-</literal> an exit code of
 319                                 the command normally considered a
 320                                 failure (i.e. non-zero exit status or
 321                                 abnormal exit due to signal) is ignored
 322                                 and considered success. If both
 323                                 <literal>-</literal> and
 324                                 <literal>@</literal> are used for the
 325                                 same command the former must precede
 326                                 the latter. Unless
 327                                 <varname>Type=forking</varname> is
 328                                 set, the process started via this
 329                                 command line will be considered the
 330                                 main process of the daemon. The
 331                                 command line accepts % specifiers as
 332                                 described in
 333                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 334
 335                                 <para>On top of that basic environment
 336                                 variable substitution is
 337                                 supported. Use
 338                                 <literal>${FOO}</literal> as part of a
 339                                 word, or as word of its own on the
 340                                 command line, in which case it will be
 341                                 replaced by the value of the
 342                                 environment variable including all
 343                                 whitespace it contains, resulting in a
 344                                 single argument.  Use
 345                                 <literal>$FOO</literal> as a separate
 346                                 word on the command line, in which
 347                                 case it will be replaced by the value
 348                                 of the environment variable split up
 349                                 at whitespace, resulting in no or more
 350                                 arguments. Note that the first
 351                                 argument (i.e. the program to execute)
 352                                 may not be a variable, and must be a
 353                                 literal and absolute path
 354                                 name.</para></listitem>
 355                         </varlistentry>
 356
 357                         <varlistentry>
 358                                 <term><varname>ExecStartPre=</varname></term>
 359                                 <term><varname>ExecStartPost=</varname></term>
 360                                 <listitem><para>Additional commands
 361                                 that are executed before (resp. after)
 362                                 the command in
 363                                 <varname>ExecStart=</varname>. Multiple
 364                                 command lines may be concatenated in a
 365                                 single directive, by separating them
 366                                 by semicolons (these semicolons must
 367                                 be passed as separate words). In that
 368                                 case, the commands are executed one
 369                                 after the other,
 370                                 serially. Alternatively, these
 371                                 directives may be specified more than
 372                                 once with the same effect. However,
 373                                 the latter syntax is not recommended
 374                                 for compatibility with parsers
 375                                 suitable for XDG
 376                                 <filename>.desktop</filename> files.
 377                                 Use of these settings is
 378                                 optional. Specifier and environment
 379                                 variable substitution is
 380                                 supported.</para></listitem>
 381                         </varlistentry>
 382
 383                         <varlistentry>
 384                                 <term><varname>ExecReload=</varname></term>
 385                                 <listitem><para>Commands to execute to
 386                                 trigger a configuration reload in the
 387                                 service. This argument takes multiple
 388                                 command lines, following the same
 389                                 scheme as pointed out for
 390                                 <varname>ExecStartPre=</varname>
 391                                 above. Use of this setting is
 392                                 optional. Specifier and environment
 393                                 variable substitution is supported
 394                                 here following the same scheme as for
 395                                 <varname>ExecStart=</varname>. One
 396                                 special environment variable is set:
 397                                 if known <literal>$MAINPID</literal> is
 398                                 set to the main process of the
 399                                 daemon, and may be used for command
 400                                 lines like the following:
 401                                 <command>/bin/kill -HUP
 402                                 $MAINPID</command>.</para></listitem>
 403                         </varlistentry>
 404
 405                         <varlistentry>
 406                                 <term><varname>ExecStop=</varname></term>
 407                                 <listitem><para>Commands to execute to
 408                                 stop the service started via
 409                                 <varname>ExecStart=</varname>. This
 410                                 argument takes multiple command lines,
 411                                 following the same scheme as pointed
 412                                 out for
 413                                 <varname>ExecStartPre=</varname>
 414                                 above. Use of this setting is
 415                                 optional. All processes remaining for
 416                                 a service after the commands
 417                                 configured in this option are run are
 418                                 terminated according to the
 419                                 <varname>KillMode=</varname> setting
 420                                 (see below). If this option is not
 421                                 specified the process is terminated
 422                                 right-away when service stop is
 423                                 requested. Specifier and environment
 424                                 variable substitution is supported
 425                                 (including
 426                                 <literal>$MAINPID</literal>, see
 427                                 above).</para></listitem>
 428                         </varlistentry>
 429
 430                         <varlistentry>
 431                                 <term><varname>ExecStopPost=</varname></term>
 432                                 <listitem><para>Additional commands
 433                                 that are executed after the service
 434                                 was stopped using the commands
 435                                 configured in
 436                                 <varname>ExecStop=</varname>. This
 437                                 argument takes multiple command lines,
 438                                 following the same scheme as pointed
 439                                 out for
 440                                 <varname>ExecStartPre</varname>. Use
 441                                 of these settings is
 442                                 optional. Specifier and environment
 443                                 variable substitution is
 444                                 supported.</para></listitem>
 445                         </varlistentry>
 446
 447                         <varlistentry>
 448                                 <term><varname>RestartSec=</varname></term>
 449                                 <listitem><para>Configures the time to
 450                                 sleep before restarting a service (as
 451                                 configured with
 452                                 <varname>Restart=</varname>). Takes a
 453                                 unit-less value in seconds, or a time
 454                                 span value such as "5min
 455                                 20s". Defaults to
 456                                 100ms.</para></listitem>
 457                         </varlistentry>
 458
 459                         <varlistentry>
 460                                 <term><varname>TimeoutSec=</varname></term>
 461                                 <listitem><para>Configures the time to
 462                                 wait for start-up and stop. If a
 463                                 daemon service does not signal
 464                                 start-up completion within the
 465                                 configured time the service will be
 466                                 considered failed and be shut down
 467                                 again. If a service is asked to stop
 468                                 but does not terminate in the
 469                                 specified time it will be terminated
 470                                 forcibly via SIGTERM, and after
 471                                 another delay of this time with
 472                                 SIGKILL. (See
 473                                 <varname>KillMode=</varname>
 474                                 below.) Takes a unit-less value in seconds, or a
 475                                 time span value such as "5min
 476                                 20s". Pass 0 to disable the timeout
 477                                 logic. Defaults to
 478                                 90s, except when <varname>Type=oneshot</varname> is
 479                                 used in which case the timeout
 480                                 is disabled by default.</para></listitem>
 481                         </varlistentry>
 482
 483                         <varlistentry>
 484                                 <term><varname>WatchdogSec=</varname></term>
 485                                 <listitem><para>Configures the
 486                                 watchdog timeout for a service. This
 487                                 is activated when the start-up is
 488                                 completed. The service must call
 489                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 490                                 regularly with "WATCHDOG=1" (i.e. the
 491                                 "keep-alive ping"). If the time
 492                                 between two such calls is larger than
 493                                 the configured time then the service
 494                                 is placed in a failure state. By
 495                                 setting <varname>Restart=</varname> to
 496                                 <option>on-failure</option> or
 497                                 <option>always</option> the service
 498                                 will be automatically restarted. The
 499                                 time configured here will be passed to
 500                                 the executed service process in the
 501                                 <varname>WATCHDOG_USEC=</varname>
 502                                 environment variable. This allows
 503                                 daemons to automatically enable the
 504                                 keep-alive pinging logic if watchdog
 505                                 support is enabled for the service. If
 506                                 this option is used
 507                                 <varname>NotifyAccess=</varname> (see
 508                                 below) should be set to open access to
 509                                 the notification socket provided by
 510                                 systemd. If
 511                                 <varname>NotifyAccess=</varname> is
 512                                 not set, it will be implicitly set to
 513                                 <option>main</option>. Defaults to 0,
 514                                 which disables this
 515                                 feature.</para></listitem>
 516                         </varlistentry>
 517
 518                         <varlistentry>
 519                                 <term><varname>Restart=</varname></term>
 520                                 <listitem><para>Configures whether the
 521                                 main service process shall be
 522                                 restarted when it exits. Takes one of
 523                                 <option>no</option>,
 524                                 <option>on-success</option>,
 525                                 <option>on-failure</option>,
 526                                 <option>on-abort</option> or
 527                                 <option>always</option>. If set to
 528                                 <option>no</option> (the default) the
 529                                 service will not be restarted when it
 530                                 exits. If set to
 531                                 <option>on-success</option> it will be
 532                                 restarted only when it exited cleanly,
 533                                 i.e. terminated with an exit code of
 534                                 0. If set to
 535                                 <option>on-failure</option> it will be
 536                                 restarted only when it exited with an
 537                                 exit code not equalling 0, when
 538                                 terminated by a signal, when an
 539                                 operation times out or when the
 540                                 configured watchdog timeout is
 541                                 triggered. If set to
 542                                 <option>on-abort</option> it will be
 543                                 restarted only if it exits due to
 544                                 reception of an uncaught signal. If
 545                                 set to <option>always</option> the
 546                                 service will be restarted regardless
 547                                 whether it exited cleanly or not,
 548                                 got terminated abnormally by a
 549                                 signal or hit a timeout.</para></listitem>
 550                         </varlistentry>
 551
 552                         <varlistentry>
 553                                 <term><varname>PermissionsStartOnly=</varname></term>
 554                                 <listitem><para>Takes a boolean
 555                                 argument. If true, the permission
 556                                 related execution options as
 557                                 configured with
 558                                 <varname>User=</varname> and similar
 559                                 options (see
 560                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 561                                 for more information) are only applied
 562                                 to the process started with
 563                                 <varname>ExecStart=</varname>, and not
 564                                 to the various other
 565                                 <varname>ExecStartPre=</varname>,
 566                                 <varname>ExecStartPost=</varname>,
 567                                 <varname>ExecReload=</varname>,
 568                                 <varname>ExecStop=</varname>,
 569                                 <varname>ExecStopPost=</varname>
 570                                 commands. If false, the setting is
 571                                 applied to all configured commands the
 572                                 same way. Defaults to
 573                                 false.</para></listitem>
 574                         </varlistentry>
 575
 576                         <varlistentry>
 577                                 <term><varname>RootDirectoryStartOnly=</varname></term>
 578                                 <listitem><para>Takes a boolean
 579                                 argument. If true, the root directory
 580                                 as configured with the
 581                                 <varname>RootDirectory=</varname>
 582                                 option (see
 583                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 584                                 for more information) is only applied
 585                                 to the process started with
 586                                 <varname>ExecStart=</varname>, and not
 587                                 to the various other
 588                                 <varname>ExecStartPre=</varname>,
 589                                 <varname>ExecStartPost=</varname>,
 590                                 <varname>ExecReload=</varname>,
 591                                 <varname>ExecStop=</varname>,
 592                                 <varname>ExecStopPost=</varname>
 593                                 commands. If false, the setting is
 594                                 applied to all configured commands the
 595                                 same way. Defaults to
 596                                 false.</para></listitem>
 597                         </varlistentry>
 598
 599                         <varlistentry>
 600                                 <term><varname>KillMode=</varname></term>
 601                                 <listitem><para>Specifies how
 602                                 processes of this service shall be
 603                                 killed. One of
 604                                 <option>control-group</option>,
 605                                 <option>process</option>,
 606                                 <option>none</option>.</para>
 607
 608                                 <para>If set to
 609                                 <option>control-group</option> all
 610                                 remaining processes in the control
 611                                 group of this service will be
 612                                 terminated on service stop, after the
 613                                 stop command (as configured with
 614                                 <varname>ExecStop=</varname>) is
 615                                 executed. If set to
 616                                 <option>process</option> only the main
 617                                 process itself is killed. If set to
 618                                 <option>none</option> no process is
 619                                 killed. In this case only the stop
 620                                 command will be executed on service
 621                                 stop, but no process be killed
 622                                 otherwise. Processes remaining alive
 623                                 after stop are left in their control
 624                                 group and the control group continues
 625                                 to exist after stop unless it is
 626                                 empty. Defaults to
 627                                 <option>control-group</option>.</para>
 628
 629                                 <para>Processes will first be
 630                                 terminated via SIGTERM (unless the
 631                                 signal to send is changed via
 632                                 <varname>KillSignal=</varname>). If
 633                                 then after a delay (configured via the
 634                                 <varname>TimeoutSec=</varname> option)
 635                                 processes still remain, the
 636                                 termination request is repeated with
 637                                 the SIGKILL signal (unless this is
 638                                 disabled via the
 639                                 <varname>SendSIGKILL=</varname>
 640                                 option). See
 641                                 <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 642                                 for more
 643                                 information.</para></listitem>
 644                         </varlistentry>
 645
 646                         <varlistentry>
 647                                 <term><varname>KillSignal=</varname></term>
 648                                 <listitem><para>Specifies which signal
 649                                 to use when killing a
 650                                 service. Defaults to SIGTERM.
 651                                 </para></listitem>
 652                         </varlistentry>
 653
 654                         <varlistentry>
 655                                 <term><varname>SendSIGKILL=</varname></term>
 656                                 <listitem><para>Specifies whether to
 657                                 send SIGKILL to remaining processes
 658                                 after a timeout, if the normal
 659                                 shutdown procedure left processes of
 660                                 the service around. Takes a boolean
 661                                 value. Defaults to "yes".
 662                                 </para></listitem>
 663                         </varlistentry>
 664
 665                         <varlistentry>
 666                                 <term><varname>NonBlocking=</varname></term>
 667                                 <listitem><para>Set O_NONBLOCK flag
 668                                 for all file descriptors passed via
 669                                 socket-based activation. If true, all
 670                                 file descriptors >= 3 (i.e. all except
 671                                 STDIN/STDOUT/STDERR) will have
 672                                 the O_NONBLOCK flag set and hence are in
 673                                 non-blocking mode. This option is only
 674                                 useful in conjunction with a socket
 675                                 unit, as described in
 676                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
 677                                 to false.</para></listitem>
 678                         </varlistentry>
 679
 680                         <varlistentry>
 681                                 <term><varname>NotifyAccess=</varname></term>
 682                                 <listitem><para>Controls access to the
 683                                 service status notification socket, as
 684                                 accessible via the
 685                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 686                                 call. Takes one of
 687                                 <option>none</option> (the default),
 688                                 <option>main</option> or
 689                                 <option>all</option>. If
 690                                 <option>none</option> no daemon status
 691                                 updates are accepted from the service
 692                                 processes, all status update messages
 693                                 are ignored. If <option>main</option>
 694                                 only service updates sent from the
 695                                 main process of the service are
 696                                 accepted. If <option>all</option> all
 697                                 services updates from all members of
 698                                 the service's control group are
 699                                 accepted. This option should be set to
 700                                 open access to the notification socket
 701                                 when using
 702                                 <varname>Type=notify</varname> or
 703                                 <varname>WatchdogUsec=</varname> (see
 704                                 above). If those options are used but
 705                                 <varname>NotifyAccess=</varname> not
 706                                 configured it will be implicitly set
 707                                 to
 708                                 <option>main</option>.</para></listitem>
 709                         </varlistentry>
 710
 711                         <varlistentry>
 712                                 <term><varname>Sockets=</varname></term>
 713                                 <listitem><para>Specifies the name of
 714                                 the socket units this service shall
 715                                 inherit the sockets from when the
 716                                 service is started. Normally it
 717                                 should not be necessary to use this
 718                                 setting as all sockets whose unit
 719                                 shares the same name as the service
 720                                 (ignoring the different suffix of course)
 721                                 are passed to the spawned
 722                                 process.</para>
 723
 724                                 <para>Note that the same socket may be
 725                                 passed to multiple processes at the
 726                                 same time. Also note that a different
 727                                 service may be activated on incoming
 728                                 traffic than inherits the sockets. Or
 729                                 in other words: The
 730                                 <varname>Service=</varname> setting of
 731                                 <filename>.socket</filename> units
 732                                 doesn't have to match the inverse of the
 733                                 <varname>Sockets=</varname> setting of
 734                                 the <filename>.service</filename> it
 735                                 refers to.</para></listitem>
 736                         </varlistentry>
 737
 738                         <varlistentry>
 739                                 <term><varname>StartLimitInterval=</varname></term>
 740                                 <term><varname>StartLimitBurst=</varname></term>
 741
 742                                 <listitem><para>Configure service
 743                                 start rate limiting. By default
 744                                 services which are started more often
 745                                 than 5 times within 10s are not
 746                                 permitted to start any more times
 747                                 until the 10s interval ends. With
 748                                 these two options this rate limiting
 749                                 may be modified. Use
 750                                 <varname>StartLimitInterval=</varname>
 751                                 to configure the checking interval
 752                                 (defaults to 10s, set to 0 to disable
 753                                 any kind of rate limiting). Use
 754                                 <varname>StartLimitBurst=</varname> to
 755                                 configure how many starts per interval
 756                                 are allowed (defaults to 5). These
 757                                 configuration options are particularly
 758                                 useful in conjunction with
 759                                 <varname>Restart=</varname>.</para></listitem>
 760                         </varlistentry>
 761
 762                         <varlistentry>
 763                                 <term><varname>StartLimitAction=</varname></term>
 764
 765                                 <listitem><para>Configure the action
 766                                 to take if the rate limit configured
 767                                 with
 768                                 <varname>StartLimitInterval=</varname>
 769                                 and
 770                                 <varname>StartLimitBurst=</varname> is
 771                                 hit. Takes one of
 772                                 <option>none</option>,
 773                                 <option>reboot</option>,
 774                                 <option>reboot-force</option> or
 775                                 <option>reboot-immediate</option>. If
 776                                 <option>none</option> is set,
 777                                 hitting the rate limit will trigger no
 778                                 action besides that the start will not
 779                                 be
 780                                 permitted. <option>reboot</option>
 781                                 causes a reboot following the normal
 782                                 shutdown procedure (i.e. equivalent to
 783                                 <command>systemctl reboot</command>),
 784                                 <option>reboot-force</option> causes
 785                                 an forced reboot which will terminate
 786                                 all processes forcibly but should
 787                                 cause no dirty file systems on reboot
 788                                 (i.e. equivalent to <command>systemctl
 789                                 reboot -f</command>) and
 790                                 <option>reboot-immediate</option>
 791                                 causes immediate execution of the
 792                                 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 793                                 system call, which might result in
 794                                 data loss.  Defaults to
 795                                 <option>none</option>.</para></listitem>
 796                         </varlistentry>
 797
 798                 </variablelist>
 799         </refsect1>
 800
 801         <refsect1>
 802                 <title>Compatibility Options</title>
 803
 804                 <para>The following options are also available in the
 805                 <literal>[Service]</literal> section, but exist purely
 806                 for compatibility reasons and should not be used in
 807                 newly written service files.</para>
 808
 809                 <variablelist>
 810                         <varlistentry>
 811                                 <term><varname>SysVStartPriority=</varname></term>
 812                                 <listitem><para>Set the SysV start
 813                                 priority to use to order this service
 814                                 in relation to SysV services lacking
 815                                 LSB headers. This option is only
 816                                 necessary to fix ordering in relation
 817                                 to legacy SysV services, that have no
 818                                 ordering information encoded in the
 819                                 script headers. As such it should only
 820                                 be used as temporary compatibility
 821                                 option, and not be used in new unit
 822                                 files. Almost always it is a better
 823                                 choice to add explicit ordering
 824                                 directives via
 825                                 <varname>After=</varname> or
 826                                 <varname>Before=</varname>,
 827                                 instead. For more details see
 828                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
 829                                 used, pass an integer value in the
 830                                 range 0-99.</para></listitem>
 831                         </varlistentry>
 832
 833                         <varlistentry>
 834                                 <term><varname>FsckPassNo=</varname></term>
 835                                 <listitem><para>Set the fsck passno
 836                                 priority to use to order this service
 837                                 in relation to other file system
 838                                 checking services. This option is only
 839                                 necessary to fix ordering in relation
 840                                 to fsck jobs automatically created for
 841                                 all <filename>/etc/fstab</filename>
 842                                 entries with a value in the fs_passno
 843                                 column > 0. As such it should only be
 844                                 used as option for fsck
 845                                 services. Almost always it is a better
 846                                 choice to add explicit ordering
 847                                 directives via
 848                                 <varname>After=</varname> or
 849                                 <varname>Before=</varname>,
 850                                 instead. For more details see
 851                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
 852                                 used, pass an integer value in the
 853                                 same range as
 854                                 <filename>/etc/fstab</filename>'s
 855                                 fs_passno column. See
 856                                 <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 857                                 for details.</para></listitem>
 858                         </varlistentry>
 859
 860                 </variablelist>
 861         </refsect1>
 862
 863         <refsect1>
 864                   <title>See Also</title>
 865                   <para>
 866                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 867                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 868                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 869                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 870                   </para>
 871         </refsect1>
 872
 873 </refentry>