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