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
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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 neither
 143                                 <varname>Type=</varname> nor
 144                                 <varname>BusName=</varname> are
 145                                 specified), it is expected that the
 146                                 process configured with
 147                                 <varname>ExecStart=</varname> is the
 148                                 main process of the service. In this
 149                                 mode, if the process offers
 150                                 functionality to other processes on
 151                                 the system, its communication channels
 152                                 should be installed before the daemon
 153                                 is started up (e.g. sockets set up by
 154                                 systemd, via socket activation), as
 155                                 systemd will immediately proceed
 156                                 starting follow-up units.</para>
 157
 158                                 <para>If set to
 159                                 <option>forking</option>, it is
 160                                 expected that the process configured
 161                                 with <varname>ExecStart=</varname>
 162                                 will call <function>fork()</function>
 163                                 as part of its start-up. The parent process is
 164                                 expected to exit when start-up is
 165                                 complete and all communication
 166                                 channels are set up. The child continues
 167                                 to run as the main daemon
 168                                 process. This is the behavior of
 169                                 traditional UNIX daemons. If this
 170                                 setting is used, it is recommended to
 171                                 also use the
 172                                 <varname>PIDFile=</varname> option, so
 173                                 that systemd can identify the main
 174                                 process of the daemon. systemd will
 175                                 proceed starting follow-up units as
 176                                 soon as the parent process
 177                                 exits.</para>
 178
 179                                 <para>Behavior of
 180                                 <option>oneshot</option> is similar
 181                                 to <option>simple</option>, however
 182                                 it is expected that the process has to
 183                                 exit before systemd starts follow-up
 184                                 units. <varname>RemainAfterExit=</varname>
 185                                 is particularly useful for this type
 186                                 of service.</para>
 187
 188                                 <para>Behavior of
 189                                 <option>dbus</option> is similar to
 190                                 <option>simple</option>, however it is
 191                                 expected that the daemon acquires a
 192                                 name on the D-Bus bus, as configured
 193                                 by
 194                                 <varname>BusName=</varname>. systemd
 195                                 will proceed starting follow-up units
 196                                 after the D-Bus bus name has been
 197                                 acquired. Service units with this
 198                                 option configured implicitly gain
 199                                 dependencies on the
 200                                 <filename>dbus.socket</filename>
 201                                 unit. This type is the default if
 202                                 <varname>BusName=</varname> is
 203                                 specified.</para>
 204
 205                                 <para>Behavior of
 206                                 <option>notify</option> is similar to
 207                                 <option>simple</option>, however it is
 208                                 expected that the daemon sends a
 209                                 notification message via
 210                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 211                                 or an equivalent call when it finished
 212                                 starting up. systemd will proceed
 213                                 starting follow-up units after this
 214                                 notification message has been sent. If
 215                                 this option is used,
 216                                 <varname>NotifyAccess=</varname> (see
 217                                 below) should be set to open access to
 218                                 the notification socket provided by
 219                                 systemd. If
 220                                 <varname>NotifyAccess=</varname> is
 221                                 not set, it will be implicitly set to
 222                                 <option>main</option>. Note that
 223                                 currently
 224                                 <varname>Type=</varname><option>notify</option>
 225                                 will not work if used in combination with
 226                                 <varname>PrivateNetwork=</varname><option>yes</option>.</para>
 227
 228                                 <para>Behavior of
 229                                 <option>idle</option> is very similar
 230                                 to <option>simple</option>, however
 231                                 actual execution of the service
 232                                 binary is delayed until all jobs are
 233                                 dispatched. This may be used to avoid
 234                                 interleaving of output of shell
 235                                 services with the status output on the
 236                                 console.</para>
 237                                 </listitem>
 238                         </varlistentry>
 239
 240                         <varlistentry>
 241                                 <term><varname>RemainAfterExit=</varname></term>
 242
 243                                 <listitem><para>Takes a boolean value
 244                                 that specifies whether the service
 245                                 shall be considered active even when
 246                                 all its processes exited. Defaults to
 247                                 <option>no</option>.</para>
 248                                 </listitem>
 249                         </varlistentry>
 250
 251                         <varlistentry>
 252                                 <term><varname>GuessMainPID=</varname></term>
 253
 254                                 <listitem><para>Takes a boolean value
 255                                 that specifies whether systemd should
 256                                 try to guess the main PID of a service
 257                                 if it cannot be determined
 258                                 reliably. This option is ignored
 259                                 unless <option>Type=forking</option>
 260                                 is set and <option>PIDFile=</option>
 261                                 is unset because for the other types
 262                                 or with an explicitly configured PID
 263                                 file the main PID is always known. The
 264                                 guessing algorithm might come to
 265                                 incorrect conclusions if a daemon
 266                                 consists of more than one process. If
 267                                 the main PID cannot be determined,
 268                                 failure detection and automatic
 269                                 restarting of a service will not work
 270                                 reliably. Defaults to
 271                                 <option>yes</option>.</para>
 272                                 </listitem>
 273                         </varlistentry>
 274
 275                         <varlistentry>
 276                                 <term><varname>PIDFile=</varname></term>
 277
 278                                 <listitem><para>Takes an absolute file
 279                                 name pointing to the PID file of this
 280                                 daemon. Use of this option is
 281                                 recommended for services where
 282                                 <varname>Type=</varname> is set to
 283                                 <option>forking</option>. systemd will
 284                                 read the PID of the main process of
 285                                 the daemon after start-up of the
 286                                 service. systemd will not write to the
 287                                 file configured here.</para>
 288                                 </listitem>
 289                         </varlistentry>
 290
 291                         <varlistentry>
 292                                 <term><varname>BusName=</varname></term>
 293
 294                                 <listitem><para>Takes a D-Bus bus
 295                                 name, that this service is reachable
 296                                 as. This option is mandatory for
 297                                 services where
 298                                 <varname>Type=</varname> is set to
 299                                 <option>dbus</option>, but its use
 300                                 is otherwise recommended as well if
 301                                 the process takes a name on the D-Bus
 302                                 bus.</para>
 303                                 </listitem>
 304                         </varlistentry>
 305
 306                         <varlistentry>
 307                                 <term><varname>ExecStart=</varname></term>
 308                                 <listitem><para>Commands with their
 309                                 arguments that are executed when this
 310                                 service is started. For each of the
 311                                 specified commands, the first argument
 312                                 must be an absolute and literal path
 313                                 to an executable.</para>
 314
 315                                 <para>When <varname>Type</varname> is
 316                                 not <option>oneshot</option>, only one
 317                                 command may be given. When
 318                                 <varname>Type=oneshot</varname> is
 319                                 used, more than one command may be
 320                                 specified. Multiple command lines may
 321                                 be concatenated in a single directive,
 322                                 by separating them with semicolons
 323                                 (these semicolons must be passed as
 324                                 separate words). Alternatively, this
 325                                 directive may be specified more than
 326                                 once with the same effect.
 327                                 Lone semicolons may be escaped as
 328                                 <literal>\;</literal>. If the empty
 329                                 string is assigned to this option, the
 330                                 list of commands to start is reset,
 331                                 prior assignments of this option will
 332                                 have no effect.</para>
 333
 334                                 <para>Each command line is split on
 335                                 whitespace, with the first item being
 336                                 the command to execute, and the
 337                                 subsequent items being the arguments.
 338                                 Double quotes ("...") and single
 339                                 quotes ('...') may be used, in which
 340                                 case everything until the next
 341                                 matching quote becomes part of the
 342                                 same argument. Quotes themselves are
 343                                 removed after parsing. In addition, a
 344                                 trailing backslash
 345                                 (<literal>\</literal>) may be used to
 346                                 merge lines. This syntax is intended
 347                                 to be very similar to shell syntax,
 348                                 but only the meta-characters and
 349                                 expansions described in the following
 350                                 paragraphs are understood.
 351                                 Specifically, redirection using
 352                                 <literal>&lt;</literal>,
 353                                 <literal>&lt;&lt;</literal>,
 354                                 <literal>&gt;</literal>, and
 355                                 <literal>&gt;&gt;</literal>, pipes
 356                                 using <literal>|</literal>, and
 357                                 running programs in the background
 358                                 using <literal>&amp;</literal>
 359                                 and <emphasis>other elements of shell
 360                                 syntax are not supported</emphasis>.
 361                                 </para>
 362
 363                                 <para>If more than one command is
 364                                 specified, the commands are invoked
 365                                 one by one sequentially in the order
 366                                 they appear in the unit file. If one
 367                                 of the commands fails (and is not
 368                                 prefixed with <literal>-</literal>),
 369                                 other lines are not executed and the
 370                                 unit is considered failed.</para>
 371
 372                                 <para>Unless
 373                                 <varname>Type=forking</varname> is
 374                                 set, the process started via this
 375                                 command line will be considered the
 376                                 main process of the daemon.</para>
 377
 378                                 <para>The command line accepts
 379                                 <literal>%</literal> specifiers as
 380                                 described in
 381                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 382                                 Note that the first argument of the
 383                                 command line (i.e. the program to
 384                                 execute) may not include
 385                                 specifiers.</para>
 386
 387                                 <para>Basic environment variable
 388                                 substitution is supported. Use
 389                                 <literal>${FOO}</literal> as part of a
 390                                 word, or as a word of its own on the
 391                                 command line, in which case it will be
 392                                 replaced by the value of the
 393                                 environment variable including all
 394                                 whitespace it contains, resulting in a
 395                                 single argument.  Use
 396                                 <literal>$FOO</literal> as a separate
 397                                 word on the command line, in which
 398                                 case it will be replaced by the value
 399                                 of the environment variable split up
 400                                 at whitespace, resulting in zero or
 401                                 more arguments. To pass a literal dollar sign,
 402                                 use <literal>$$</literal>. Note that the first
 403                                 argument (i.e. the program to execute)
 404                                 may not be a variable.</para>
 405
 406                                 <para>Optionally, if the absolute file
 407                                 name is prefixed with
 408                                 <literal>@</literal>, the second token
 409                                 will be passed as
 410                                 <literal>argv[0]</literal> to the
 411                                 executed process, followed by the
 412                                 further arguments specified. If the
 413                                 absolute filename is prefixed with
 414                                 <literal>-</literal>, an exit code of
 415                                 the command normally considered a
 416                                 failure (i.e. non-zero exit status or
 417                                 abnormal exit due to signal) is ignored
 418                                 and considered success. If both
 419                                 <literal>-</literal> and
 420                                 <literal>@</literal> are used, they
 421                                 can appear in either order.</para>
 422
 423                                 <para>Note that this setting does not
 424                                 directly support shell command
 425                                 lines. If shell command lines are to
 426                                 be used, they need to be passed
 427                                 explicitly to a shell implementation
 428                                 of some kind. Example:</para>
 429                                 <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'
 430                                 </programlisting>
 431
 432                                 <para>Only select environment variables that
 433                                 are set for executed commands. See
 434                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 435                                 </para>
 436
 437                                 <para>Example:</para>
 438                                 <programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"
 439                                 </programlisting>
 440                                 <para>This will execute
 441                                 <command>/bin/echo</command> two
 442                                 times, each time with one argument,
 443                                 <literal>one</literal> and
 444                                 <literal>two two</literal>,
 445                                 respectively. Since two commands are
 446                                 specified,
 447                                 <varname>Type=oneshot</varname> must
 448                                 be used.</para>
 449
 450                                 <para>Example:</para>
 451                                 <programlisting>ExecStart=/bin/echo / &gt;/dev/null &amp; \; \
 452 /bin/ls
 453                                 </programlisting>
 454                                 <para>This will execute
 455                                 <command>/bin/echo</command> with five
 456                                 arguments: <literal>/</literal>,
 457                                 <literal>&gt;/dev/null</literal>,
 458                                 <literal>&amp;</literal>,
 459                                 <literal>;</literal>, and
 460                                 <literal>/bin/ls</literal>.</para>
 461
 462                                 <para>Example:</para>
 463                                 <programlisting>Environment="ONE=one" 'TWO=two two'
 464 ExecStart=/bin/echo $ONE $TWO ${TWO}
 465                                 </programlisting>
 466                                 <para>This will execute
 467                                 <command>/bin/echo</command> with four
 468                                 arguments: <literal>one</literal>,
 469                                 <literal>two</literal>,
 470                                 <literal>two</literal>, and
 471                                 <literal>two two</literal>.</para>
 472                               </listitem>
 473                         </varlistentry>
 474
 475                         <varlistentry>
 476                                 <term><varname>ExecStartPre=</varname></term>
 477                                 <term><varname>ExecStartPost=</varname></term>
 478                                 <listitem><para>Additional commands
 479                                 that are executed before or after
 480                                 the command in
 481                                 <varname>ExecStart=</varname>, respectively.
 482                                 Syntax is the same as for
 483                                 <varname>ExecStart=</varname>, except
 484                                 that multiple command lines are allowed
 485                                 and the commands are executed one
 486                                 after the other, serially.</para>
 487
 488                                 <para>If any of those commands (not
 489                                 prefixed with <literal>-</literal>)
 490                                 fail, the rest are not executed and
 491                                 the unit is considered failed.</para>
 492                                 </listitem>
 493                         </varlistentry>
 494
 495                         <varlistentry>
 496                                 <term><varname>ExecReload=</varname></term>
 497                                 <listitem><para>Commands to execute to
 498                                 trigger a configuration reload in the
 499                                 service. This argument takes multiple
 500                                 command lines, following the same
 501                                 scheme as described for
 502                                 <varname>ExecStart=</varname>
 503                                 above. Use of this setting is
 504                                 optional. Specifier and environment
 505                                 variable substitution is supported
 506                                 here following the same scheme as for
 507                                 <varname>ExecStart=</varname>.</para>
 508
 509                                 <para>One additional special
 510                                 environment variables is set: if known
 511                                 <varname>$MAINPID</varname> is set to
 512                                 the main process of the daemon, and
 513                                 may be used for command lines like the
 514                                 following:</para>
 515
 516                                 <programlisting>/bin/kill -HUP $MAINPID</programlisting>
 517                                 </listitem>
 518                         </varlistentry>
 519
 520                         <varlistentry>
 521                                 <term><varname>ExecStop=</varname></term>
 522                                 <listitem><para>Commands to execute to
 523                                 stop the service started via
 524                                 <varname>ExecStart=</varname>. This
 525                                 argument takes multiple command lines,
 526                                 following the same scheme as described
 527                                 for <varname>ExecStart=</varname>
 528                                 above. Use of this setting is
 529                                 optional. All processes remaining for
 530                                 a service after the commands
 531                                 configured in this option are run are
 532                                 terminated according to the
 533                                 <varname>KillMode=</varname> setting
 534                                 (see
 535                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
 536                                 this option is not specified, the
 537                                 process is terminated right-away when
 538                                 service stop is requested. Specifier
 539                                 and environment variable substitution
 540                                 is supported (including
 541                                 <varname>$MAINPID</varname>, see
 542                                 above).</para></listitem>
 543                         </varlistentry>
 544
 545                         <varlistentry>
 546                                 <term><varname>ExecStopPost=</varname></term>
 547                                 <listitem><para>Additional commands
 548                                 that are executed after the service
 549                                 was stopped. This includes cases where
 550                                 the commands configured in
 551                                 <varname>ExecStop=</varname> were used,
 552                                 where the service does not have any
 553                                 <varname>ExecStop=</varname> defined, or
 554                                 where the service exited unexpectedly. This
 555                                 argument takes multiple command lines,
 556                                 following the same scheme as described
 557                                 for <varname>ExecStart</varname>. Use
 558                                 of these settings is
 559                                 optional. Specifier and environment
 560                                 variable substitution is
 561                                 supported.</para></listitem>
 562                         </varlistentry>
 563
 564                         <varlistentry>
 565                                 <term><varname>RestartSec=</varname></term>
 566                                 <listitem><para>Configures the time to
 567                                 sleep before restarting a service (as
 568                                 configured with
 569                                 <varname>Restart=</varname>). Takes a
 570                                 unit-less value in seconds, or a time
 571                                 span value such as "5min
 572                                 20s". Defaults to
 573                                 100ms.</para></listitem>
 574                         </varlistentry>
 575
 576                         <varlistentry>
 577                                 <term><varname>TimeoutStartSec=</varname></term>
 578                                 <listitem><para>Configures the time to
 579                                 wait for start-up. If a
 580                                 daemon service does not signal
 581                                 start-up completion within the
 582                                 configured time, the service will be
 583                                 considered failed and be shut down
 584                                 again.
 585                                 Takes a unit-less value in seconds, or a
 586                                 time span value such as "5min
 587                                 20s". Pass 0 to disable the timeout
 588                                 logic. Defaults to <varname>TimeoutStartSec=</varname> from the
 589                                 manager configuration file, except when
 590                                 <varname>Type=oneshot</varname> is
 591                                 used, in which case the timeout
 592                                 is disabled by default.
 593                                 </para></listitem>
 594                         </varlistentry>
 595
 596                         <varlistentry>
 597                                 <term><varname>TimeoutStopSec=</varname></term>
 598                                 <listitem><para>Configures the time to
 599                                 wait for stop. If a service is asked
 600                                 to stop but does not terminate in the
 601                                 specified time, it will be terminated
 602                                 forcibly via <constant>SIGTERM</constant>, and after
 603                                 another delay of this time with
 604                                 <constant>SIGKILL</constant> (See
 605                                 <varname>KillMode=</varname>
 606                                 in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
 607                                 Takes a unit-less value in seconds, or a
 608                                 time span value such as "5min
 609                                 20s". Pass 0 to disable the timeout
 610                                 logic. Defaults to <varname>TimeoutStartSec=</varname> from the
 611                                 manager configuration file.
 612                                 </para></listitem>
 613                         </varlistentry>
 614
 615                         <varlistentry>
 616                                 <term><varname>TimeoutSec=</varname></term>
 617                                 <listitem><para>A shorthand for configuring
 618                                 both <varname>TimeoutStartSec=</varname>
 619                                 and <varname>TimeoutStopSec=</varname>
 620                                 to the specified value.
 621                                 </para></listitem>
 622                         </varlistentry>
 623
 624                         <varlistentry>
 625                                 <term><varname>WatchdogSec=</varname></term>
 626                                 <listitem><para>Configures the
 627                                 watchdog timeout for a service. The
 628                                 watchdog is activated when the start-up is
 629                                 completed. The service must call
 630                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 631                                 regularly with "WATCHDOG=1" (i.e. the
 632                                 "keep-alive ping"). If the time
 633                                 between two such calls is larger than
 634                                 the configured time, then the service
 635                                 is placed in a failure state. By
 636                                 setting <varname>Restart=</varname> to
 637                                 <option>on-failure</option> or
 638                                 <option>always</option>, the service
 639                                 will be automatically restarted. The
 640                                 time configured here will be passed to
 641                                 the executed service process in the
 642                                 <varname>WATCHDOG_USEC=</varname>
 643                                 environment variable. This allows
 644                                 daemons to automatically enable the
 645                                 keep-alive pinging logic if watchdog
 646                                 support is enabled for the service. If
 647                                 this option is used,
 648                                 <varname>NotifyAccess=</varname> (see
 649                                 below) should be set to open access to
 650                                 the notification socket provided by
 651                                 systemd. If
 652                                 <varname>NotifyAccess=</varname> is
 653                                 not set, it will be implicitly set to
 654                                 <option>main</option>. Defaults to 0,
 655                                 which disables this
 656                                 feature.</para></listitem>
 657                         </varlistentry>
 658
 659                         <varlistentry>
 660                                 <term><varname>Restart=</varname></term>
 661                                 <listitem><para>Configures whether the
 662                                 service shall be restarted when the
 663                                 service process exits, is killed,
 664                                 or a timeout is reached. The service
 665                                 process may be the main service
 666                                 process, but also one of the processes
 667                                 specified with
 668                                 <varname>ExecStartPre=</varname>,
 669                                 <varname>ExecStartPost=</varname>,
 670                                 <varname>ExecStopPre=</varname>,
 671                                 <varname>ExecStopPost=</varname>, or
 672                                 <varname>ExecReload=</varname>.
 673                                 When the death of the process is a
 674                                 result of systemd operation (e.g. service
 675                                 stop or restart), the service will not be
 676                                 restarted. Timeouts include missing
 677                                 the watchdog "keep-alive ping"
 678                                 deadline and a service start, reload,
 679                                 and stop operation timeouts.</para>
 680
 681                                 <para>Takes one of
 682                                 <option>no</option>,
 683                                 <option>on-success</option>,
 684                                 <option>on-failure</option>,
 685                                 <option>on-watchdog</option>,
 686                                 <option>on-abort</option>, or
 687                                 <option>always</option>. If set to
 688                                 <option>no</option> (the default), the
 689                                 service will not be restarted. If set to
 690                                 <option>on-success</option>, it will be
 691                                 restarted only when the service process
 692                                 exits cleanly.
 693                                 In this context, a clean exit means
 694                                 an exit code of 0, or one of the signals
 695                                 <constant>SIGHUP</constant>, <constant>SIGINT</constant>, <constant>SIGTERM</constant>, or <constant>SIGPIPE</constant>, and
 696                                 additionally, exit statuses and signals
 697                                 specified in <varname>SuccessExitStatus=</varname>.
 698                                 If set to <option>on-failure</option>,
 699                                 the service will be restarted when the
 700                                 process exits with an nonzero exit code,
 701                                 is terminated by a signal (including on
 702                                 core dump), when an operation (such as
 703                                 service reload) times out, and when the
 704                                 configured watchdog timeout is triggered.
 705                                 If set to
 706                                 <option>on-abort</option>, the service
 707                                 will be restarted only if the service
 708                                 process exits due to an uncaught
 709                                 signal not specified as a clean exit
 710                                 status.
 711                                 If set to
 712                                 <option>on-watchdog</option>, the service
 713                                 will be restarted only if the watchdog
 714                                 timeout for the service expires.
 715                                 If set to
 716                                 <option>always</option>, the service
 717                                 will be restarted regardless of whether
 718                                 it exited cleanly or not, got
 719                                 terminated abnormally by a signal or
 720                                 hit a timeout.</para>
 721
 722                                 <para>In addition to the above settings,
 723                                 the service will not be restarted if the
 724                                 exit code or signal is specified in
 725                                 <varname>RestartPreventExitStatus=</varname>
 726                                 (see below).</para></listitem>
 727                         </varlistentry>
 728
 729                         <varlistentry>
 730                                 <term><varname>SuccessExitStatus=</varname></term>
 731                                 <listitem><para>Takes a list of exit
 732                                 status definitions that when returned
 733                                 by the main service process will be
 734                                 considered successful termination, in
 735                                 addition to the normal successful exit
 736                                 code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
 737                                 <constant>SIGTERM</constant> and <constant>SIGPIPE</constant>. Exit status
 738                                 definitions can either be numeric exit
 739                                 codes or termination signal names,
 740                                 separated by spaces. Example:
 741                                 <literal>SuccessExitStatus=1 2 8
 742                                 <constant>SIGKILL</constant></literal>, ensures that exit
 743                                 codes 1, 2, 8 and the termination
 744                                 signal <constant>SIGKILL</constant> are considered clean
 745                                 service terminations. This option may
 746                                 appear more than once in which case
 747                                 the list of successful exit statuses
 748                                 is merged. If the empty string is
 749                                 assigned to this option, the list is
 750                                 reset, all prior assignments of this
 751                                 option will have no
 752                                 effect.</para></listitem>
 753                         </varlistentry>
 754
 755                         <varlistentry>
 756                                 <term><varname>RestartPreventExitStatus=</varname></term>
 757                                 <listitem><para>Takes a list of exit
 758                                 status definitions that when returned
 759                                 by the main service process will
 760                                 prevent automatic service restarts
 761                                 regardless of the restart setting
 762                                 configured with
 763                                 <varname>Restart=</varname>. Exit
 764                                 status definitions can either be
 765                                 numeric exit codes or termination
 766                                 signal names, and are separated by
 767                                 spaces. Defaults to the empty list, so
 768                                 that by default no exit status is
 769                                 excluded from the configured restart
 770                                 logic. Example:
 771                                 <literal>RestartPreventExitStatus=1 6
 772                                 SIGABRT</literal>, ensures that exit
 773                                 codes 1 and 6 and the termination
 774                                 signal SIGABRT will not result in
 775                                 automatic service restarting. This
 776                                 option may appear more than once in
 777                                 which case the list of restart preventing
 778                                 statuses is merged. If the empty
 779                                 string is assigned to this option, the
 780                                 list is reset, all prior assignments
 781                                 of this option will have no
 782                                 effect.</para></listitem>
 783                         </varlistentry>
 784
 785                         <varlistentry>
 786                                 <term><varname>PermissionsStartOnly=</varname></term>
 787                                 <listitem><para>Takes a boolean
 788                                 argument. If true, the permission
 789                                 related execution options as
 790                                 configured with
 791                                 <varname>User=</varname> and similar
 792                                 options (see
 793                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 794                                 for more information) are only applied
 795                                 to the process started with
 796                                 <varname>ExecStart=</varname>, and not
 797                                 to the various other
 798                                 <varname>ExecStartPre=</varname>,
 799                                 <varname>ExecStartPost=</varname>,
 800                                 <varname>ExecReload=</varname>,
 801                                 <varname>ExecStop=</varname>,
 802                                 <varname>ExecStopPost=</varname>
 803                                 commands. If false, the setting is
 804                                 applied to all configured commands the
 805                                 same way. Defaults to
 806                                 false.</para></listitem>
 807                         </varlistentry>
 808
 809                         <varlistentry>
 810                                 <term><varname>RootDirectoryStartOnly=</varname></term>
 811                                 <listitem><para>Takes a boolean
 812                                 argument. If true, the root directory
 813                                 as configured with the
 814                                 <varname>RootDirectory=</varname>
 815                                 option (see
 816                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 817                                 for more information) is only applied
 818                                 to the process started with
 819                                 <varname>ExecStart=</varname>, and not
 820                                 to the various other
 821                                 <varname>ExecStartPre=</varname>,
 822                                 <varname>ExecStartPost=</varname>,
 823                                 <varname>ExecReload=</varname>,
 824                                 <varname>ExecStop=</varname>,
 825                                 <varname>ExecStopPost=</varname>
 826                                 commands. If false, the setting is
 827                                 applied to all configured commands the
 828                                 same way. Defaults to
 829                                 false.</para></listitem>
 830                         </varlistentry>
 831
 832                         <varlistentry>
 833                                 <term><varname>NonBlocking=</varname></term>
 834                                 <listitem><para>Set O_NONBLOCK flag
 835                                 for all file descriptors passed via
 836                                 socket-based activation. If true, all
 837                                 file descriptors >= 3 (i.e. all except
 838                                 STDIN/STDOUT/STDERR) will have
 839                                 the O_NONBLOCK flag set and hence are in
 840                                 non-blocking mode. This option is only
 841                                 useful in conjunction with a socket
 842                                 unit, as described in
 843                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
 844                                 to false.</para></listitem>
 845                         </varlistentry>
 846
 847                         <varlistentry>
 848                                 <term><varname>NotifyAccess=</varname></term>
 849                                 <listitem><para>Controls access to the
 850                                 service status notification socket, as
 851                                 accessible via the
 852                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 853                                 call. Takes one of
 854                                 <option>none</option> (the default),
 855                                 <option>main</option> or
 856                                 <option>all</option>. If
 857                                 <option>none</option>, no daemon status
 858                                 updates are accepted from the service
 859                                 processes, all status update messages
 860                                 are ignored. If <option>main</option>,
 861                                 only service updates sent from the
 862                                 main process of the service are
 863                                 accepted. If <option>all</option>, all
 864                                 services updates from all members of
 865                                 the service's control group are
 866                                 accepted. This option should be set to
 867                                 open access to the notification socket
 868                                 when using
 869                                 <varname>Type=notify</varname> or
 870                                 <varname>WatchdogSec=</varname> (see
 871                                 above). If those options are used but
 872                                 <varname>NotifyAccess=</varname> is not
 873                                 configured, it will be implicitly set
 874                                 to
 875                                 <option>main</option>.</para></listitem>
 876                         </varlistentry>
 877
 878                         <varlistentry>
 879                                 <term><varname>Sockets=</varname></term>
 880                                 <listitem><para>Specifies the name of
 881                                 the socket units this service shall
 882                                 inherit the sockets from when the
 883                                 service is started. Normally it
 884                                 should not be necessary to use this
 885                                 setting as all sockets whose unit
 886                                 shares the same name as the service
 887                                 (ignoring the different suffix of course)
 888                                 are passed to the spawned
 889                                 process.</para>
 890
 891                                 <para>Note that the same socket may be
 892                                 passed to multiple processes at the
 893                                 same time. Also note that a different
 894                                 service may be activated on incoming
 895                                 traffic than inherits the sockets. Or
 896                                 in other words: the
 897                                 <varname>Service=</varname> setting of
 898                                 <filename>.socket</filename> units
 899                                 does not have to match the inverse of
 900                                 the <varname>Sockets=</varname>
 901                                 setting of the
 902                                 <filename>.service</filename> it
 903                                 refers to.</para>
 904
 905                                 <para>This option may appear more than
 906                                 once, in which case the list of socket
 907                                 units is merged. If the empty string
 908                                 is assigned to this option, the list of
 909                                 sockets is reset, all prior uses of
 910                                 this setting will have no
 911                                 effect.</para></listitem>
 912                         </varlistentry>
 913
 914                         <varlistentry>
 915                                 <term><varname>StartLimitInterval=</varname></term>
 916                                 <term><varname>StartLimitBurst=</varname></term>
 917
 918                                 <listitem><para>Configure service
 919                                 start rate limiting. By default,
 920                                 services which are started more often
 921                                 than 5 times within 10s are not
 922                                 permitted to start any more times
 923                                 until the 10s interval ends. With
 924                                 these two options, this rate limiting
 925                                 may be modified. Use
 926                                 <varname>StartLimitInterval=</varname>
 927                                 to configure the checking interval (defaults to
 928                                 <varname>DefaultStartLimitInterval=</varname> in
 929                                 manager configuration file, set to 0 to disable
 930                                 any kind of rate limiting). Use
 931                                 <varname>StartLimitBurst=</varname> to
 932                                 configure how many starts per interval
 933                                 are allowed (defaults to
 934                                 <varname>DefaultStartLimitBurst=</varname> in
 935                                 manager configuration file). These
 936                                 configuration options are particularly
 937                                 useful in conjunction with
 938                                 <varname>Restart=</varname>, however
 939                                 apply to all kinds of starts
 940                                 (including manual), not just those
 941                                 triggered by the
 942                                 <varname>Restart=</varname> logic.
 943                                 Note that units which are configured
 944                                 for <varname>Restart=</varname> and
 945                                 which reach the start limit are not
 946                                 attempted to be restarted anymore,
 947                                 however they may still be restarted
 948                                 manually at a later point from which
 949                                 point on the restart logic is again
 950                                 activated. Note that
 951                                 <command>systemctl
 952                                 reset-failed</command> will cause the
 953                                 restart rate counter for a service to
 954                                 be flushed, which is useful if the
 955                                 administrator wants to manually start
 956                                 a service and the start limit
 957                                 interferes with
 958                                 that.</para></listitem>
 959                         </varlistentry>
 960
 961                         <varlistentry>
 962                                 <term><varname>StartLimitAction=</varname></term>
 963
 964                                 <listitem><para>Configure the action
 965                                 to take if the rate limit configured
 966                                 with
 967                                 <varname>StartLimitInterval=</varname>
 968                                 and
 969                                 <varname>StartLimitBurst=</varname> is
 970                                 hit. Takes one of
 971                                 <option>none</option>,
 972                                 <option>reboot</option>,
 973                                 <option>reboot-force</option> or
 974                                 <option>reboot-immediate</option>. If
 975                                 <option>none</option> is set,
 976                                 hitting the rate limit will trigger no
 977                                 action besides that the start will not
 978                                 be
 979                                 permitted. <option>reboot</option>
 980                                 causes a reboot following the normal
 981                                 shutdown procedure (i.e. equivalent to
 982                                 <command>systemctl reboot</command>),
 983                                 <option>reboot-force</option> causes
 984                                 an forced reboot which will terminate
 985                                 all processes forcibly but should
 986                                 cause no dirty file systems on reboot
 987                                 (i.e. equivalent to <command>systemctl
 988                                 reboot -f</command>) and
 989                                 <option>reboot-immediate</option>
 990                                 causes immediate execution of the
 991                                 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 992                                 system call, which might result in
 993                                 data loss.  Defaults to
 994                                 <option>none</option>.</para></listitem>
 995                         </varlistentry>
 996
 997                 </variablelist>
 998
 999                 <para>Check
1000                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1001                 and
1002                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1003                 for more settings.</para>
1004
1005         </refsect1>
1006
1007         <refsect1>
1008                 <title>Compatibility Options</title>
1009
1010                 <para>The following options are also available in the
1011                 <literal>[Service]</literal> section, but exist purely
1012                 for compatibility reasons and should not be used in
1013                 newly written service files.</para>
1014
1015                 <variablelist class='unit-directives'>
1016                         <varlistentry>
1017                                 <term><varname>SysVStartPriority=</varname></term>
1018                                 <listitem><para>Set the SysV start
1019                                 priority to use to order this service
1020                                 in relation to SysV services lacking
1021                                 LSB headers. This option is only
1022                                 necessary to fix ordering in relation
1023                                 to legacy SysV services, that have no
1024                                 ordering information encoded in the
1025                                 script headers. As such it should only
1026                                 be used as temporary compatibility
1027                                 option, and not be used in new unit
1028                                 files. Almost always it is a better
1029                                 choice to add explicit ordering
1030                                 directives via
1031                                 <varname>After=</varname> or
1032                                 <varname>Before=</varname>,
1033                                 instead. For more details see
1034                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
1035                                 used, pass an integer value in the
1036                                 range 0-99.</para></listitem>
1037                         </varlistentry>
1038
1039                 </variablelist>
1040         </refsect1>
1041
1042         <refsect1>
1043                   <title>See Also</title>
1044                   <para>
1045                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1046                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1047                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1048                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1049                           <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1050                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1051                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
1052                   </para>
1053         </refsect1>
1054
1055 </refentry>