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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  21   You should have received a copy of the GNU Lesser General Public License
  22   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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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.</para>
  79
  80                 <para>Unless <varname>DefaultDependencies=</varname>
  81                 is set to <option>false</option>, service units will
  82                 implicitly have dependencies of type
  83                 <varname>Requires=</varname> and
  84                 <varname>After=</varname> on
  85                 <filename>basic.target</filename> as well as
  86                 dependencies of type <varname>Conflicts=</varname> and
  87                 <varname>Before=</varname> on
  88                 <filename>shutdown.target</filename>. These ensure
  89                 that normal service units pull in basic system
  90                 initialization, and are terminated cleanly prior to
  91                 system shutdown. Only services involved with early
  92                 boot or late system shutdown should disable this
  93                 option.</para>
  94
  95                 <para>If a service is requested under a certain name
  96                 but no unit configuration file is found, systemd looks
  97                 for a SysV init script by the same name (with the
  98                 <filename>.service</filename> suffix removed) and
  99                 dynamically creates a service unit from that
 100                 script. This is useful for compatibility with
 101                 SysV. Note that this compatibility is quite
 102                 comprehensive but not 100%. For details about the
 103                 incompatibilities see the <ulink
 104                 url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
 105                 with SysV</ulink> document.
 106                 </para>
 107         </refsect1>
 108
 109         <refsect1>
 110                 <title>Options</title>
 111
 112                 <para>Service files must include a
 113                 <literal>[Service]</literal> section, which carries
 114                 information about the service and the process it
 115                 supervises. A number of options that may be used in
 116                 this section are shared with other unit types. These
 117                 options are documented in
 118                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 119                 and
 120                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 121                 options specific to the <literal>[Service]</literal>
 122                 section of service units are the following:</para>
 123
 124                 <variablelist class='unit-directives'>
 125                         <varlistentry>
 126                                 <term><varname>Type=</varname></term>
 127
 128                                 <listitem><para>Configures the process
 129                                 start-up type for this service
 130                                 unit. One of <option>simple</option>,
 131                                 <option>forking</option>,
 132                                 <option>oneshot</option>,
 133                                 <option>dbus</option>,
 134                                 <option>notify</option> or
 135                                 <option>idle</option>.</para>
 136
 137                                 <para>If set to
 138                                 <option>simple</option> (the default
 139                                 value if <varname>BusName=</varname>
 140                                 is not specified) it is expected that
 141                                 the process configured with
 142                                 <varname>ExecStart=</varname> is the
 143                                 main process of the service. In this
 144                                 mode, if the process offers
 145                                 functionality to other processes on
 146                                 the system its communication channels
 147                                 should be installed before the daemon
 148                                 is started up (e.g. sockets set up by
 149                                 systemd, via socket activation), as
 150                                 systemd will immediately proceed
 151                                 starting follow-up units.</para>
 152
 153                                 <para>If set to
 154                                 <option>forking</option> it is
 155                                 expected that the process configured
 156                                 with <varname>ExecStart=</varname>
 157                                 will call <function>fork()</function>
 158                                 as part of its start-up. The parent process is
 159                                 expected to exit when start-up is
 160                                 complete and all communication
 161                                 channels set up. The child continues
 162                                 to run as the main daemon
 163                                 process. This is the behavior of
 164                                 traditional UNIX daemons. If this
 165                                 setting is used, it is recommended to
 166                                 also use the
 167                                 <varname>PIDFile=</varname> option, so
 168                                 that systemd can identify the main
 169                                 process of the daemon. systemd will
 170                                 proceed starting follow-up units as
 171                                 soon as the parent process
 172                                 exits.</para>
 173
 174                                 <para>Behavior of
 175                                 <option>oneshot</option> is similar
 176                                 to <option>simple</option>, however
 177                                 it is expected that the process has to
 178                                 exit before systemd starts follow-up
 179                                 units. <varname>RemainAfterExit=</varname>
 180                                 is particularly useful for this type
 181                                 of service.</para>
 182
 183                                 <para>Behavior of
 184                                 <option>dbus</option> is similar to
 185                                 <option>simple</option>, however it is
 186                                 expected that the daemon acquires a
 187                                 name on the D-Bus bus, as configured
 188                                 by
 189                                 <varname>BusName=</varname>. systemd
 190                                 will proceed starting follow-up units
 191                                 after the D-Bus bus name has been
 192                                 acquired. Service units with this
 193                                 option configured implicitly gain
 194                                 dependencies on the
 195                                 <filename>dbus.socket</filename>
 196                                 unit. This type is the default if
 197                                 <varname>BusName=</varname> is
 198                                 specified.</para>
 199
 200                                 <para>Behavior of
 201                                 <option>notify</option> is similar to
 202                                 <option>simple</option>, however it is
 203                                 expected that the daemon sends a
 204                                 notification message via
 205                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 206                                 or an equivalent call when it finished
 207                                 starting up. systemd will proceed
 208                                 starting follow-up units after this
 209                                 notification message has been sent. If
 210                                 this option is used
 211                                 <varname>NotifyAccess=</varname> (see
 212                                 below) should be set to open access to
 213                                 the notification socket provided by
 214                                 systemd. If
 215                                 <varname>NotifyAccess=</varname> is
 216                                 not set, it will be implicitly set to
 217                                 <option>main</option>.</para>
 218
 219                                 <para>Behavior of
 220                                 <option>idle</option> is very similar
 221                                 to <option>simple</option>, however
 222                                 actual execution of the service
 223                                 binary is delayed until all jobs are
 224                                 dispatched. This may be used to avoid
 225                                 interleaving of output of shell
 226                                 services with the status output on the
 227                                 console.</para>
 228                                 </listitem>
 229                         </varlistentry>
 230
 231                         <varlistentry>
 232                                 <term><varname>RemainAfterExit=</varname></term>
 233
 234                                 <listitem><para>Takes a boolean value
 235                                 that specifies whether the service
 236                                 shall be considered active even when
 237                                 all its processes exited. Defaults to
 238                                 <option>no</option>.</para>
 239                                 </listitem>
 240                         </varlistentry>
 241
 242                         <varlistentry>
 243                                 <term><varname>GuessMainPID=</varname></term>
 244
 245                                 <listitem><para>Takes a boolean value
 246                                 that specifies whether systemd should
 247                                 try to guess the main PID of a service
 248                                 if it cannot be determined
 249                                 reliably. This option is ignored
 250                                 unless <option>Type=forking</option>
 251                                 is set and <option>PIDFile=</option>
 252                                 is unset because for the other types
 253                                 or with an explicitly configured PID
 254                                 file the main PID is always known. The
 255                                 guessing algorithm might come to
 256                                 incorrect conclusions if a daemon
 257                                 consists of more than one process. If
 258                                 the main PID cannot be determined
 259                                 failure detection and automatic
 260                                 restarting of a service will not work
 261                                 reliably. Defaults to
 262                                 <option>yes</option>.</para>
 263                                 </listitem>
 264                         </varlistentry>
 265
 266                         <varlistentry>
 267                                 <term><varname>PIDFile=</varname></term>
 268
 269                                 <listitem><para>Takes an absolute file
 270                                 name pointing to the PID file of this
 271                                 daemon. Use of this option is
 272                                 recommended for services where
 273                                 <varname>Type=</varname> is set to
 274                                 <option>forking</option>. systemd will
 275                                 read the PID of the main process of
 276                                 the daemon after start-up of the
 277                                 service. systemd will not write to the
 278                                 file configured here.</para>
 279                                 </listitem>
 280                         </varlistentry>
 281
 282                         <varlistentry>
 283                                 <term><varname>BusName=</varname></term>
 284
 285                                 <listitem><para>Takes a D-Bus bus
 286                                 name, that this service is reachable
 287                                 as. This option is mandatory for
 288                                 services where
 289                                 <varname>Type=</varname> is set to
 290                                 <option>dbus</option>, but its use
 291                                 is otherwise recommended as well if
 292                                 the process takes a name on the D-Bus
 293                                 bus.</para>
 294                                 </listitem>
 295                         </varlistentry>
 296
 297                         <varlistentry>
 298                                 <term><varname>ExecStart=</varname></term>
 299                                 <listitem><para>Commands with their
 300                                 arguments that are executed when this
 301                                 service is started. The first
 302                                 argument must be an absolute path
 303                                 name.</para>
 304
 305                                 <para>When <varname>Type</varname> is
 306                                 not <option>oneshot</option>, only one
 307                                 command may be given. When
 308                                 <varname>Type=oneshot</varname> is
 309                                 used, more than one command may be
 310                                 specified. Multiple command lines may
 311                                 be concatenated in a single directive,
 312                                 by separating them with semicolons
 313                                 (these semicolons must be passed as
 314                                 separate words). Alternatively, this
 315                                 directive may be specified more than
 316                                 once with the same effect. However,
 317                                 the latter syntax is not recommended
 318                                 for compatibility with parsers
 319                                 suitable for XDG
 320                                 <filename>.desktop</filename> files.
 321                                 Lone semicolons may be escaped as
 322                                 '<literal>\;</literal>'. If the empty
 323                                 string is assigned to this option the
 324                                 list of commands to start is reset,
 325                                 prior assignments of this option will
 326                                 have no effect.</para>
 327
 328                                 <para>If more than one command is
 329                                 specified, the commands are invoked
 330                                 one by one sequentially in the order
 331                                 they appear in the unit file. If one
 332                                 of the commands fails (and is not
 333                                 prefixed with '<literal>-</literal>'),
 334                                 other lines are not executed and the
 335                                 unit is considered failed.</para>
 336
 337                                 <para>Unless
 338                                 <varname>Type=forking</varname> is
 339                                 set, the process started via this
 340                                 command line will be considered the
 341                                 main process of the daemon.</para>
 342
 343                                 <para>The command line accepts
 344                                 '<literal>%</literal>' specifiers as
 345                                 described in
 346                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Note
 347                                 that the first argument of the command
 348                                 line (i.e. the program to execute) may
 349                                 not include specifiers.</para>
 350
 351                                 <para>Basic environment variable
 352                                 substitution is supported. Use
 353                                 <literal>${FOO}</literal> as part of a
 354                                 word, or as a word of its own on the
 355                                 command line, in which case it will be
 356                                 replaced by the value of the
 357                                 environment variable including all
 358                                 whitespace it contains, resulting in a
 359                                 single argument.  Use
 360                                 <literal>$FOO</literal> as a separate
 361                                 word on the command line, in which
 362                                 case it will be replaced by the value
 363                                 of the environment variable split up
 364                                 at whitespace, resulting in zero or
 365                                 more arguments. Note that the first
 366                                 argument (i.e. the program to execute)
 367                                 may not be a variable, since it must
 368                                 be a literal and absolute path
 369                                 name.</para>
 370
 371                                 <para>Optionally, if the absolute file
 372                                 name is prefixed with
 373                                 '<literal>@</literal>', the second token
 374                                 will be passed as
 375                                 <literal>argv[0]</literal> to the
 376                                 executed process, followed by the
 377                                 further arguments specified. If the
 378                                 absolute file name is prefixed with
 379                                 '<literal>-</literal>' an exit code of
 380                                 the command normally considered a
 381                                 failure (i.e. non-zero exit status or
 382                                 abnormal exit due to signal) is ignored
 383                                 and considered success. If both
 384                                 '<literal>-</literal>' and
 385                                 '<literal>@</literal>' are used they
 386                                 can appear in either order.</para>
 387
 388                                 <para>Note that this setting does not
 389                                 directly support shell command
 390                                 lines. If shell command lines are to
 391                                 be used they need to be passed
 392                                 explicitly to a shell implementation
 393                                 of some kind. Example:</para>
 394                                 <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'
 395                                 </programlisting>
 396
 397                                 <para>For services run by a user
 398                                 instance of systemd the special
 399                                 environment variable
 400                                 <varname>$MANAGERPID</varname> is set
 401                                 to the PID of the systemd
 402                                 instance.</para>
 403                                 </listitem>
 404                         </varlistentry>
 405
 406                         <varlistentry>
 407                                 <term><varname>ExecStartPre=</varname></term>
 408                                 <term><varname>ExecStartPost=</varname></term>
 409                                 <listitem><para>Additional commands
 410                                 that are executed before or after
 411                                 the command in
 412                                 <varname>ExecStart=</varname>, respectively.
 413                                 Syntax is the same as for
 414                                 <varname>ExecStart=</varname>, except
 415                                 that multiple command lines are allowed
 416                                 and the commands are executed one
 417                                 after the other, serially.</para>
 418
 419                                 <para>If any of those commands (not
 420                                 prefixed with '<literal>-</literal>')
 421                                 fail, the rest are not executed and
 422                                 the unit is considered failed.</para>
 423                                 </listitem>
 424                         </varlistentry>
 425
 426                         <varlistentry>
 427                                 <term><varname>ExecReload=</varname></term>
 428                                 <listitem><para>Commands to execute to
 429                                 trigger a configuration reload in the
 430                                 service. This argument takes multiple
 431                                 command lines, following the same
 432                                 scheme as described for
 433                                 <varname>ExecStart=</varname>
 434                                 above. Use of this setting is
 435                                 optional. Specifier and environment
 436                                 variable substitution is supported
 437                                 here following the same scheme as for
 438                                 <varname>ExecStart=</varname>.</para>
 439
 440                                 <para>One additional special
 441                                 environment variables is set: if known
 442                                 <varname>$MAINPID</varname> is set to
 443                                 the main process of the daemon, and
 444                                 may be used for command lines like the
 445                                 following:</para>
 446
 447                                 <programlisting>/bin/kill -HUP $MAINPID</programlisting>
 448                                 </listitem>
 449                         </varlistentry>
 450
 451                         <varlistentry>
 452                                 <term><varname>ExecStop=</varname></term>
 453                                 <listitem><para>Commands to execute to
 454                                 stop the service started via
 455                                 <varname>ExecStart=</varname>. This
 456                                 argument takes multiple command lines,
 457                                 following the same scheme as described
 458                                 for <varname>ExecStart=</varname>
 459                                 above. Use of this setting is
 460                                 optional. All processes remaining for
 461                                 a service after the commands
 462                                 configured in this option are run are
 463                                 terminated according to the
 464                                 <varname>KillMode=</varname> setting
 465                                 (see
 466                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
 467                                 this option is not specified the
 468                                 process is terminated right-away when
 469                                 service stop is requested. Specifier
 470                                 and environment variable substitution
 471                                 is supported (including
 472                                 <varname>$MAINPID</varname>, see
 473                                 above).</para></listitem>
 474                         </varlistentry>
 475
 476                         <varlistentry>
 477                                 <term><varname>ExecStopPost=</varname></term>
 478                                 <listitem><para>Additional commands
 479                                 that are executed after the service
 480                                 was stopped. This includes cases where
 481                                 the commands configured in
 482                                 <varname>ExecStop=</varname> were used,
 483                                 where the service doesn't have any
 484                                 <varname>ExecStop=</varname> defined, or
 485                                 where the service exited unexpectedly. This
 486                                 argument takes multiple command lines,
 487                                 following the same scheme as described
 488                                 for <varname>ExecStart</varname>. Use
 489                                 of these settings is
 490                                 optional. Specifier and environment
 491                                 variable substitution is
 492                                 supported.</para></listitem>
 493                         </varlistentry>
 494
 495                         <varlistentry>
 496                                 <term><varname>RestartSec=</varname></term>
 497                                 <listitem><para>Configures the time to
 498                                 sleep before restarting a service (as
 499                                 configured with
 500                                 <varname>Restart=</varname>). Takes a
 501                                 unit-less value in seconds, or a time
 502                                 span value such as "5min
 503                                 20s". Defaults to
 504                                 100ms.</para></listitem>
 505                         </varlistentry>
 506
 507                         <varlistentry>
 508                                 <term><varname>TimeoutStartSec=</varname></term>
 509                                 <listitem><para>Configures the time to
 510                                 wait for start-up. If a
 511                                 daemon service does not signal
 512                                 start-up completion within the
 513                                 configured time, the service will be
 514                                 considered failed and be shut down
 515                                 again.
 516                                 Takes a unit-less value in seconds, or a
 517                                 time span value such as "5min
 518                                 20s". Pass 0 to disable the timeout
 519                                 logic. Defaults to 90s, except when
 520                                 <varname>Type=oneshot</varname> is
 521                                 used in which case the timeout
 522                                 is disabled by default.
 523                                 </para></listitem>
 524                         </varlistentry>
 525
 526                         <varlistentry>
 527                                 <term><varname>TimeoutStopSec=</varname></term>
 528                                 <listitem><para>Configures the time to
 529                                 wait for stop. If a service is asked
 530                                 to stop but does not terminate in the
 531                                 specified time, it will be terminated
 532                                 forcibly via SIGTERM, and after
 533                                 another delay of this time with
 534                                 SIGKILL (See
 535                                 <varname>KillMode=</varname>
 536                                 in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
 537                                 Takes a unit-less value in seconds, or a
 538                                 time span value such as "5min
 539                                 20s". Pass 0 to disable the timeout
 540                                 logic. Defaults to 90s.
 541                                 </para></listitem>
 542                         </varlistentry>
 543
 544                         <varlistentry>
 545                                 <term><varname>TimeoutSec=</varname></term>
 546                                 <listitem><para>A shorthand for configuring
 547                                 both <varname>TimeoutStartSec=</varname>
 548                                 and <varname>TimeoutStopSec=</varname>
 549                                 to the specified value.
 550                                 </para></listitem>
 551                         </varlistentry>
 552
 553                         <varlistentry>
 554                                 <term><varname>WatchdogSec=</varname></term>
 555                                 <listitem><para>Configures the
 556                                 watchdog timeout for a service. This
 557                                 is activated when the start-up is
 558                                 completed. The service must call
 559                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 560                                 regularly with "WATCHDOG=1" (i.e. the
 561                                 "keep-alive ping"). If the time
 562                                 between two such calls is larger than
 563                                 the configured time then the service
 564                                 is placed in a failure state. By
 565                                 setting <varname>Restart=</varname> to
 566                                 <option>on-failure</option> or
 567                                 <option>always</option> the service
 568                                 will be automatically restarted. The
 569                                 time configured here will be passed to
 570                                 the executed service process in the
 571                                 <varname>WATCHDOG_USEC=</varname>
 572                                 environment variable. This allows
 573                                 daemons to automatically enable the
 574                                 keep-alive pinging logic if watchdog
 575                                 support is enabled for the service. If
 576                                 this option is used
 577                                 <varname>NotifyAccess=</varname> (see
 578                                 below) should be set to open access to
 579                                 the notification socket provided by
 580                                 systemd. If
 581                                 <varname>NotifyAccess=</varname> is
 582                                 not set, it will be implicitly set to
 583                                 <option>main</option>. Defaults to 0,
 584                                 which disables this
 585                                 feature.</para></listitem>
 586                         </varlistentry>
 587
 588                         <varlistentry>
 589                                 <term><varname>Restart=</varname></term>
 590                                 <listitem><para>Configures whether the
 591                                 main service process shall be
 592                                 restarted when it exits. Takes one of
 593                                 <option>no</option>,
 594                                 <option>on-success</option>,
 595                                 <option>on-failure</option>,
 596                                 <option>on-abort</option> or
 597                                 <option>always</option>. If set to
 598                                 <option>no</option> (the default) the
 599                                 service will not be restarted when it
 600                                 exits. If set to
 601                                 <option>on-success</option> it will be
 602                                 restarted only when it exited cleanly,
 603                                 i.e. terminated with an exit code of
 604                                 0. If set to
 605                                 <option>on-failure</option> it will be
 606                                 restarted only when it exited with an
 607                                 exit code not equaling 0, when
 608                                 terminated by a signal (including on
 609                                 core dump), when an operation (such as
 610                                 service reload) times out or when the
 611                                 configured watchdog timeout is
 612                                 triggered. If set to
 613                                 <option>on-abort</option> it will be
 614                                 restarted only if it exits due to
 615                                 reception of an uncaught signal
 616                                 (including on core dump). If set to
 617                                 <option>always</option> the service
 618                                 will be restarted regardless whether
 619                                 it exited cleanly or not, got
 620                                 terminated abnormally by a signal or
 621                                 hit a timeout.</para></listitem>
 622                         </varlistentry>
 623
 624                         <varlistentry>
 625                                 <term><varname>SuccessExitStatus=</varname></term>
 626                                 <listitem><para>Takes a list of exit
 627                                 status definitions that when returned
 628                                 by the main service process will be
 629                                 considered successful termination, in
 630                                 addition to the normal successful exit
 631                                 code 0 and the signals SIGHUP, SIGINT,
 632                                 SIGTERM and SIGPIPE. Exit status
 633                                 definitions can either be numeric exit
 634                                 codes or termination signal names, and
 635                                 are separated by spaces. Example:
 636                                 "<literal>SuccessExitStatus=1 2 8
 637                                 SIGKILL</literal>", ensures that exit
 638                                 codes 1, 2, 8 and the termination
 639                                 signal SIGKILL are considered clean
 640                                 service terminations. This option may
 641                                 appear more than once in which case
 642                                 the list of successful exit statuses
 643                                 is merged. If the empty string is
 644                                 assigned to this option the list is
 645                                 reset, all prior assignments of this
 646                                 option will have no
 647                                 effect.</para></listitem>
 648                         </varlistentry>
 649
 650                         <varlistentry>
 651                                 <term><varname>RestartPreventExitStatus=</varname></term>
 652                                 <listitem><para>Takes a list of exit
 653                                 status definitions that when returned
 654                                 by the main service process will
 655                                 prevent automatic service restarts
 656                                 regardless of the restart setting
 657                                 configured with
 658                                 <varname>Restart=</varname>. Exit
 659                                 status definitions can either be
 660                                 numeric exit codes or termination
 661                                 signal names, and are separated by
 662                                 spaces. Defaults to the empty list, so
 663                                 that by default no exit status is
 664                                 excluded from the configured restart
 665                                 logic. Example:
 666                                 "<literal>RestartPreventExitStatus=1 6
 667                                 SIGABRT</literal>", ensures that exit
 668                                 codes 1 and 6 and the termination
 669                                 signal SIGABRT will not result in
 670                                 automatic service restarting. This
 671                                 option may appear more than once in
 672                                 which case the list of restart preventing
 673                                 statuses is merged. If the empty
 674                                 string is assigned to this option the
 675                                 list is reset, all prior assignments
 676                                 of this option will have no
 677                                 effect.</para></listitem>
 678                         </varlistentry>
 679
 680                         <varlistentry>
 681                                 <term><varname>PermissionsStartOnly=</varname></term>
 682                                 <listitem><para>Takes a boolean
 683                                 argument. If true, the permission
 684                                 related execution options as
 685                                 configured with
 686                                 <varname>User=</varname> and similar
 687                                 options (see
 688                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 689                                 for more information) are only applied
 690                                 to the process started with
 691                                 <varname>ExecStart=</varname>, and not
 692                                 to the various other
 693                                 <varname>ExecStartPre=</varname>,
 694                                 <varname>ExecStartPost=</varname>,
 695                                 <varname>ExecReload=</varname>,
 696                                 <varname>ExecStop=</varname>,
 697                                 <varname>ExecStopPost=</varname>
 698                                 commands. If false, the setting is
 699                                 applied to all configured commands the
 700                                 same way. Defaults to
 701                                 false.</para></listitem>
 702                         </varlistentry>
 703
 704                         <varlistentry>
 705                                 <term><varname>RootDirectoryStartOnly=</varname></term>
 706                                 <listitem><para>Takes a boolean
 707                                 argument. If true, the root directory
 708                                 as configured with the
 709                                 <varname>RootDirectory=</varname>
 710                                 option (see
 711                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 712                                 for more information) is only applied
 713                                 to the process started with
 714                                 <varname>ExecStart=</varname>, and not
 715                                 to the various other
 716                                 <varname>ExecStartPre=</varname>,
 717                                 <varname>ExecStartPost=</varname>,
 718                                 <varname>ExecReload=</varname>,
 719                                 <varname>ExecStop=</varname>,
 720                                 <varname>ExecStopPost=</varname>
 721                                 commands. If false, the setting is
 722                                 applied to all configured commands the
 723                                 same way. Defaults to
 724                                 false.</para></listitem>
 725                         </varlistentry>
 726
 727                         <varlistentry>
 728                                 <term><varname>NonBlocking=</varname></term>
 729                                 <listitem><para>Set O_NONBLOCK flag
 730                                 for all file descriptors passed via
 731                                 socket-based activation. If true, all
 732                                 file descriptors >= 3 (i.e. all except
 733                                 STDIN/STDOUT/STDERR) will have
 734                                 the O_NONBLOCK flag set and hence are in
 735                                 non-blocking mode. This option is only
 736                                 useful in conjunction with a socket
 737                                 unit, as described in
 738                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
 739                                 to false.</para></listitem>
 740                         </varlistentry>
 741
 742                         <varlistentry>
 743                                 <term><varname>NotifyAccess=</varname></term>
 744                                 <listitem><para>Controls access to the
 745                                 service status notification socket, as
 746                                 accessible via the
 747                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 748                                 call. Takes one of
 749                                 <option>none</option> (the default),
 750                                 <option>main</option> or
 751                                 <option>all</option>. If
 752                                 <option>none</option> no daemon status
 753                                 updates are accepted from the service
 754                                 processes, all status update messages
 755                                 are ignored. If <option>main</option>
 756                                 only service updates sent from the
 757                                 main process of the service are
 758                                 accepted. If <option>all</option> all
 759                                 services updates from all members of
 760                                 the service's control group are
 761                                 accepted. This option should be set to
 762                                 open access to the notification socket
 763                                 when using
 764                                 <varname>Type=notify</varname> or
 765                                 <varname>WatchdogSec=</varname> (see
 766                                 above). If those options are used but
 767                                 <varname>NotifyAccess=</varname> not
 768                                 configured it will be implicitly set
 769                                 to
 770                                 <option>main</option>.</para></listitem>
 771                         </varlistentry>
 772
 773                         <varlistentry>
 774                                 <term><varname>Sockets=</varname></term>
 775                                 <listitem><para>Specifies the name of
 776                                 the socket units this service shall
 777                                 inherit the sockets from when the
 778                                 service is started. Normally it
 779                                 should not be necessary to use this
 780                                 setting as all sockets whose unit
 781                                 shares the same name as the service
 782                                 (ignoring the different suffix of course)
 783                                 are passed to the spawned
 784                                 process.</para>
 785
 786                                 <para>Note that the same socket may be
 787                                 passed to multiple processes at the
 788                                 same time. Also note that a different
 789                                 service may be activated on incoming
 790                                 traffic than inherits the sockets. Or
 791                                 in other words: the
 792                                 <varname>Service=</varname> setting of
 793                                 <filename>.socket</filename> units
 794                                 doesn't have to match the inverse of
 795                                 the <varname>Sockets=</varname>
 796                                 setting of the
 797                                 <filename>.service</filename> it
 798                                 refers to.</para>
 799
 800                                 <para>This option may appear more than
 801                                 once, in which case the list of socket
 802                                 units is merged. If the empty string
 803                                 is assigned to this option the list of
 804                                 sockets is reset, all prior uses of
 805                                 this setting will have no
 806                                 effect.</para></listitem>
 807                         </varlistentry>
 808
 809                         <varlistentry>
 810                                 <term><varname>StartLimitInterval=</varname></term>
 811                                 <term><varname>StartLimitBurst=</varname></term>
 812
 813                                 <listitem><para>Configure service
 814                                 start rate limiting. By default
 815                                 services which are started more often
 816                                 than 5 times within 10s are not
 817                                 permitted to start any more times
 818                                 until the 10s interval ends. With
 819                                 these two options this rate limiting
 820                                 may be modified. Use
 821                                 <varname>StartLimitInterval=</varname>
 822                                 to configure the checking interval
 823                                 (defaults to 10s, set to 0 to disable
 824                                 any kind of rate limiting). Use
 825                                 <varname>StartLimitBurst=</varname> to
 826                                 configure how many starts per interval
 827                                 are allowed (defaults to 5). These
 828                                 configuration options are particularly
 829                                 useful in conjunction with
 830                                 <varname>Restart=</varname>, however
 831                                 apply to all kinds of starts
 832                                 (including manual), not just those
 833                                 triggered by the
 834                                 <varname>Restart=</varname> logic.
 835                                 Note that units which are configured
 836                                 for <varname>Restart=</varname> and
 837                                 which reach the start limit are not
 838                                 attempted to be restarted anymore,
 839                                 however they may still be restarted
 840                                 manually at a later point from which
 841                                 point on the restart logic is again
 842                                 activated. Note that
 843                                 <command>systemctl
 844                                 reset-failed</command> will cause the
 845                                 restart rate counter for a service to
 846                                 be flushed, which is useful if the
 847                                 administrator wants to manually start
 848                                 a service and the start limit
 849                                 interferes with
 850                                 that.</para></listitem>
 851                         </varlistentry>
 852
 853                         <varlistentry>
 854                                 <term><varname>StartLimitAction=</varname></term>
 855
 856                                 <listitem><para>Configure the action
 857                                 to take if the rate limit configured
 858                                 with
 859                                 <varname>StartLimitInterval=</varname>
 860                                 and
 861                                 <varname>StartLimitBurst=</varname> is
 862                                 hit. Takes one of
 863                                 <option>none</option>,
 864                                 <option>reboot</option>,
 865                                 <option>reboot-force</option> or
 866                                 <option>reboot-immediate</option>. If
 867                                 <option>none</option> is set,
 868                                 hitting the rate limit will trigger no
 869                                 action besides that the start will not
 870                                 be
 871                                 permitted. <option>reboot</option>
 872                                 causes a reboot following the normal
 873                                 shutdown procedure (i.e. equivalent to
 874                                 <command>systemctl reboot</command>),
 875                                 <option>reboot-force</option> causes
 876                                 an forced reboot which will terminate
 877                                 all processes forcibly but should
 878                                 cause no dirty file systems on reboot
 879                                 (i.e. equivalent to <command>systemctl
 880                                 reboot -f</command>) and
 881                                 <option>reboot-immediate</option>
 882                                 causes immediate execution of the
 883                                 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 884                                 system call, which might result in
 885                                 data loss.  Defaults to
 886                                 <option>none</option>.</para></listitem>
 887                         </varlistentry>
 888
 889                 </variablelist>
 890
 891                 <para>Check
 892                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 893                 and
 894                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 895                 for more settings.</para>
 896
 897         </refsect1>
 898
 899         <refsect1>
 900                 <title>Compatibility Options</title>
 901
 902                 <para>The following options are also available in the
 903                 <literal>[Service]</literal> section, but exist purely
 904                 for compatibility reasons and should not be used in
 905                 newly written service files.</para>
 906
 907                 <variablelist class='unit-directives'>
 908                         <varlistentry>
 909                                 <term><varname>SysVStartPriority=</varname></term>
 910                                 <listitem><para>Set the SysV start
 911                                 priority to use to order this service
 912                                 in relation to SysV services lacking
 913                                 LSB headers. This option is only
 914                                 necessary to fix ordering in relation
 915                                 to legacy SysV services, that have no
 916                                 ordering information encoded in the
 917                                 script headers. As such it should only
 918                                 be used as temporary compatibility
 919                                 option, and not be used in new unit
 920                                 files. Almost always it is a better
 921                                 choice to add explicit ordering
 922                                 directives via
 923                                 <varname>After=</varname> or
 924                                 <varname>Before=</varname>,
 925                                 instead. For more details see
 926                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
 927                                 used, pass an integer value in the
 928                                 range 0-99.</para></listitem>
 929                         </varlistentry>
 930
 931                         <varlistentry>
 932                                 <term><varname>FsckPassNo=</varname></term>
 933                                 <listitem><para>Set the fsck passno
 934                                 priority to use to order this service
 935                                 in relation to other file system
 936                                 checking services. This option is only
 937                                 necessary to fix ordering in relation
 938                                 to fsck jobs automatically created for
 939                                 all <filename>/etc/fstab</filename>
 940                                 entries with a value in the fs_passno
 941                                 column > 0. As such it should only be
 942                                 used as option for fsck
 943                                 services. Almost always it is a better
 944                                 choice to add explicit ordering
 945                                 directives via
 946                                 <varname>After=</varname> or
 947                                 <varname>Before=</varname>,
 948                                 instead. For more details see
 949                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
 950                                 used, pass an integer value in the
 951                                 same range as
 952                                 <filename>/etc/fstab</filename>'s
 953                                 fs_passno column. See
 954                                 <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 955                                 for details.</para></listitem>
 956                         </varlistentry>
 957
 958                 </variablelist>
 959         </refsect1>
 960
 961         <refsect1>
 962                   <title>See Also</title>
 963                   <para>
 964                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 965                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 966                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 967                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 968                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 969                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 970                   </para>
 971         </refsect1>
 972
 973 </refentry>