man/systemd.service.xml

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   7   This file is part of systemd.
   8
   9   Copyright 2010 Lennart Poettering
  10
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  12   under the terms of the GNU General Public License as published by
  13   the Free Software Foundation; either version 2 of the License, or
  14   (at your option) any later version.
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  24
  25 <refentry id="systemd.service">
  26         <refentryinfo>
  27                 <title>systemd.service</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemd.service</refentrytitle>
  42                 <manvolnum>5</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.service</refname>
  47                 <refpurpose>systemd service configuration files</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>systemd.service</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para>A unit configuration file whose name ends in
  58                 .service encodes information about a process
  59                 controlled and supervised by systemd.</para>
  60
  61                 <para>This man page lists the configuration options
  62                 specific to this unit type. See
  63                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  64                 for the common options of all unit configuration
  65                 files. The common configuration items are configured
  66                 in the generic [Unit] and [Install] sections. The
  67                 service specific configuration options are configured
  68                 in the [Service] section.</para>
  69
  70                 <para>Additional options are listed in <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  71         </refsect1>
  72
  73         <refsect1>
  74                 <title>Options</title>
  75
  76                 <para>Service files must include a [Service] section,
  77                 which carries information about the service and the
  78                 process it supervises. A number of options that may be
  79                 used in this section are shared with other unit
  80                 types. These options are documented in
  81                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
  82                 options specific to the [Service] section of service
  83                 units are the following:</para>
  84
  85                 <variablelist>
  86                         <varlistentry>
  87                                 <term><varname>Type=</varname></term>
  88
  89                                 <listitem><para>Configures the process
  90                                 start-up type for this service
  91                                 unit. One of <option>simple</option>,
  92                                 <option>forking</option>,
  93                                 <option>finish</option>,
  94                                 <option>dbus</option>,
  95                                 <option>notify</option>.</para>
  96
  97                                 <para>If set to
  98                                 <option>simple</option> (the default
  99                                 value) it is expected that the process
 100                                 configured with
 101                                 <varname>ExecStart=</varname> is the
 102                                 main process of the service. In this
 103                                 mode, communication channels must be
 104                                 installed before the daemon is started
 105                                 up (e.g. sockets set up by systemd,
 106                                 via socket activation), as systemd
 107                                 will immediately proceed starting
 108                                 follow-up units.</para>
 109
 110                                 <para>If set to
 111                                 <option>forking</option> it is
 112                                 expected that the process configured
 113                                 with <varname>ExecStart=</varname>
 114                                 will start up and call
 115                                 <function>fork()</function>. The
 116                                 parent process is expected to finish
 117                                 when start-up is complete and all
 118                                 communication channels set up. The
 119                                 child continues to run as the main
 120                                 daemon process. This is the behaviour
 121                                 of traditional UNIX daemons. If this
 122                                 setting is used, it is recommended to
 123                                 also use the
 124                                 <varname>PIDFile=</varname> option, so
 125                                 that systemd can identify the main
 126                                 process of the daemon. systemd will
 127                                 proceed starting follow-up units as
 128                                 soon as the parent process
 129                                 exits.</para>
 130
 131                                 <para>Behaviour of
 132                                 <option>finish</option> is similar
 133                                 to <option>simple</option>, however
 134                                 it is expected that the process has to
 135                                 exit before systemd starts follow-up
 136                                 units. <varname>ValidNoProcess=</varname>
 137                                 is particularly useful for this type
 138                                 of service.</para>
 139
 140                                 <para>Behaviour of
 141                                 <option>dbus</option> is similar to
 142                                 <option>simple</option>, however it
 143                                 is expected that the daemon acquires a
 144                                 name on the D-Bus bus, as configured
 145                                 by
 146                                 <varname>BusName=</varname>. systemd
 147                                 will proceed starting follow-up units
 148                                 after the D-Bus bus name has been
 149                                 acquired.</para>
 150
 151                                 <para>Behaviour of
 152                                 <option>notify</option> is similar to
 153                                 <option>simple</option>, however it is
 154                                 expected that the daemon sends a
 155                                 notification message via
 156                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 157                                 or an equivalent call when it finished
 158                                 starting up. systemd will proceed
 159                                 starting follow-up units after this
 160                                 notification message has been sent. If
 161                                 this option is used
 162                                 <option>NotifyAccess=</option> (see
 163                                 below) must be set to open access to
 164                                 the notification socket provided by
 165                                 systemd.</para>
 166                                 </listitem>
 167                         </varlistentry>
 168
 169                         <varlistentry>
 170                                 <term><varname>ValidNoProcess=</varname></term>
 171
 172                                 <listitem><para>Takes a boolean value
 173                                 that specifies whether the service
 174                                 shall be considered active even when
 175                                 all its processes exited. Defaults to
 176                                 <option>no</option>.</para>
 177                                 </listitem>
 178                         </varlistentry>
 179
 180                         <varlistentry>
 181                                 <term><varname>PIDFile=</varname></term>
 182
 183                                 <listitem><para>Takes an absolute file
 184                                 name pointing to the PID file of this
 185                                 daemon. Use of this option is
 186                                 recommended for services where
 187                                 <varname>Type=</varname> is set to
 188                                 <option>forking</option>.</para>
 189                                 </listitem>
 190                         </varlistentry>
 191
 192                         <varlistentry>
 193                                 <term><varname>BusName=</varname></term>
 194
 195                                 <listitem><para>Takes a D-Bus bus
 196                                 name, where this service is reachable
 197                                 as. This option is mandatory for
 198                                 services where
 199                                 <varname>Type=</varname> is set to
 200                                 <option>dbus</option>, but its use
 201                                 is otherwise recommended as well if
 202                                 the process takes a name on the D-Bus
 203                                 bus.</para>
 204                                 </listitem>
 205                         </varlistentry>
 206
 207                         <varlistentry>
 208                                 <term><varname>ExecStart=</varname></term>
 209                                 <listitem><para>Takes a command line
 210                                 that is executed when this service
 211                                 shall be started up. The first token
 212                                 of the command line must be an
 213                                 absolute file name, then followed by
 214                                 arguments for the process. It is
 215                                 mandatory to set this option for all
 216                                 services. This option may not be
 217                                 specified more than once. Optionally,
 218                                 if the absolute file name is prefixed
 219                                 with @, the second token will be
 220                                 passed as argv[0] to the executed
 221                                 process, followed by the further
 222                                 arguments specified. Unless
 223                                 <option>Type=forking</option> is set,
 224                                 the process started via this command
 225                                 line will be considered the main
 226                                 process of the
 227                                 daemon.</para></listitem>
 228                         </varlistentry>
 229
 230                         <varlistentry>
 231                                 <term><varname>ExecStartPre=</varname></term>
 232                                 <term><varname>ExecStartPost=</varname></term>
 233                                 <listitem><para>Additional commands
 234                                 that are executed before (resp. after)
 235                                 the command in
 236                                 <varname>ExecStart=</varname>. If
 237                                 specified more than once, all commands
 238                                 are executed one after the other,
 239                                 serially. Use of these settings is
 240                                 optional.</para></listitem>
 241                         </varlistentry>
 242
 243                         <varlistentry>
 244                                 <term><varname>ExecReload=</varname></term>
 245                                 <listitem><para>Commands to execute to
 246                                 trigger a configuration reload in the
 247                                 service. If used more than once, all
 248                                 commands are executed one after the
 249                                 other, serially. Use of this setting is optional.
 250                                 </para></listitem>
 251                         </varlistentry>
 252
 253                         <varlistentry>
 254                                 <term><varname>ExecStop=</varname></term>
 255                                 <listitem><para>Commands to execute to
 256                                 stop the service started via
 257                                 <varname>ExecStart=</varname>. If used
 258                                 more than once, all commands are
 259                                 executed one after the other,
 260                                 serially. Use of this setting is
 261                                 optional. All processes remaining for
 262                                 a service after the commands
 263                                 configured in this option are run are
 264                                 terminated according to the
 265                                 <varname>KillMode=</varname> setting
 266                                 (see below). If this option is not
 267                                 specified the process is terminated
 268                                 right-away when service stop is
 269                                 requested.</para></listitem>
 270                         </varlistentry>
 271
 272                         <varlistentry>
 273                                 <term><varname>ExecStopPost=</varname></term>
 274                                 <listitem><para>Additional commands
 275                                 that are executed after the service
 276                                 was stopped using the commands
 277                                 configured in
 278                                 <varname>ExecStop=</varname>. If
 279                                 specified more than once, all commands
 280                                 are executed one after the other,
 281                                 serially. Use of these settings is
 282                                 optional.</para></listitem>
 283                         </varlistentry>
 284
 285                         <varlistentry>
 286                                 <term><varname>RestartSec=</varname></term>
 287                                 <listitem><para>Configures the time to
 288                                 sleep before restarting a service (as
 289                                 configured with
 290                                 <varname>Restart=</varname>). Takes a
 291                                 unit-less value in seconds, or a time
 292                                 span value such as "5min
 293                                 20s". Defaults to
 294                                 100ms.</para></listitem>
 295                         </varlistentry>
 296
 297                         <varlistentry>
 298                                 <term><varname>TimeoutSec=</varname></term>
 299                                 <listitem><para>Configures the time to
 300                                 wait for start-up and stop. If a
 301                                 daemon service does not signal
 302                                 start-up completion within the
 303                                 configured time the service will be
 304                                 considered failed and be shut down
 305                                 again. If a service is asked to stop
 306                                 but does not terminate in the
 307                                 specified time it will be terminated
 308                                 forcibly via SIGTERM, and after
 309                                 another delay of this time with
 310                                 SIGKILL. (See
 311                                 <option>KillMode=</option>
 312                                 below.) Takes a unit-less value in seconds, or a
 313                                 time span value such as "5min
 314                                 20s". Pass 0 to disable the timeout
 315                                 logic. Defaults to
 316                                 60s.</para></listitem>
 317                         </varlistentry>
 318
 319                         <varlistentry>
 320                                 <term><varname>Restart=</varname></term>
 321                                 <listitem><para>Configures whether the
 322                                 main service process shall be restarted when
 323                                 it exists. Takes one of
 324                                 <option>once</option>,
 325                                 <option>restart-on-success</option> or
 326                                 <option>restart-always</option>. If
 327                                 set to <option>once</option> (the
 328                                 default) the service will not be
 329                                 restarted when it exits. If set to
 330                                 <option>restart-on-success</option> it
 331                                 will be restarted only when it exited
 332                                 cleanly, i.e. terminated with an exit
 333                                 code of 0. If set to
 334                                 <option>restart-always</option> the
 335                                 service will be restarted regardless
 336                                 whether it exited cleanly or not, or
 337                                 got terminated abnormally by a
 338                                 signal.</para></listitem>
 339                         </varlistentry>
 340
 341                         <varlistentry>
 342                                 <term><varname>PermissionsStartOnly=</varname></term>
 343                                 <listitem><para>Takes a boolean
 344                                 argument. If true, the permission
 345                                 related execution options as
 346                                 configured with
 347                                 <varname>User=</varname> and similar
 348                                 options (see
 349                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 350                                 for more information) are only applied
 351                                 to the process started with
 352                                 <varname>ExecStart=</varname>, and not
 353                                 to the various other
 354                                 <varname>ExecStartPre=</varname>,
 355                                 <varname>ExecStartPost=</varname>,
 356                                 <varname>ExecReload=</varname>,
 357                                 <varname>ExecStop=</varname>,
 358                                 <varname>ExecStopPost=</varname>
 359                                 commands. If false, the setting is
 360                                 applied to all configured commands the
 361                                 same way. Defaults to
 362                                 false.</para></listitem>
 363                         </varlistentry>
 364
 365                         <varlistentry>
 366                                 <term><varname>RootDirectoryStartOnly=</varname></term>
 367                                 <listitem><para>Takes a boolean
 368                                 argument. If true, the root directory
 369                                 as configured with the
 370                                 <varname>RootDirectory=</varname>
 371                                 option (see
 372                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 373                                 for more information) is only applied
 374                                 to the process started with
 375                                 <varname>ExecStart=</varname>, and not
 376                                 to the various other
 377                                 <varname>ExecStartPre=</varname>,
 378                                 <varname>ExecStartPost=</varname>,
 379                                 <varname>ExecReload=</varname>,
 380                                 <varname>ExecStop=</varname>,
 381                                 <varname>ExecStopPost=</varname>
 382                                 commands. If false, the setting is
 383                                 applied to all configured commands the
 384                                 same way. Defaults to
 385                                 false.</para></listitem>
 386                         </varlistentry>
 387
 388                         <varlistentry>
 389                                 <term><varname>SysVStartPriority=</varname></term>
 390                                 <listitem><para>Set the SysV start
 391                                 priority to use to order this service
 392                                 in relation to SysV services lacking
 393                                 LSB headers. This option is only
 394                                 necessary to fix ordering in relation
 395                                 to legacy SysV services, that have no
 396                                 ordering information encoded in the
 397                                 script headers. As such it should only
 398                                 be used as temporary compatibility
 399                                 option, and not be used in new unit
 400                                 files. Almost always it is a better
 401                                 choice to add explicit ordering
 402                                 directives via
 403                                 <varname>After=</varname> or
 404                                 <varname>Before=</varname>,
 405                                 instead. For more details see
 406                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
 407                                 used, pass an integer value in the
 408                                 range 0-99.</para></listitem>
 409                         </varlistentry>
 410
 411                         <varlistentry>
 412                                 <term><varname>KillMode=</varname></term>
 413                                 <listitem><para>Specifies how
 414                                 processes of this service shall be
 415                                 killed. One of
 416                                 <option>control-group</option>,
 417                                 <option>process-group</option>,
 418                                 <option>process</option>,
 419                                 <option>none</option>.</para>
 420
 421                                 <para>If set to
 422                                 <option>control-group</option> all
 423                                 remaining processes in the control
 424                                 group of this service will be
 425                                 terminated on service stop, after the
 426                                 stop command (as configured with
 427                                 <varname>ExecStop=</varname>) is
 428                                 executed. If set to
 429                                 <option>process-group</option> only
 430                                 the members of the process group of
 431                                 the main service process are
 432                                 killed. If set to
 433                                 <option>process</option> only the main
 434                                 process itself is killed. If set to
 435                                 <option>none</option> no process is
 436                                 killed. In this case only the stop
 437                                 command will be executed on service
 438                                 stop, but no process be killed
 439                                 otherwise. Processes remaining alive
 440                                 after stop are left in their control
 441                                 group and the control group continues
 442                                 to exist after stop unless it is
 443                                 empty. Defaults to
 444                                 <option>control-croup</option>.</para>
 445
 446                                 <para>Processes will first be
 447                                 terminated via SIGTERM. If then after
 448                                 a delay (configured via the
 449                                 <option>TimeoutSec=</option> option)
 450                                 processes still remain, the
 451                                 termination request is repeated with
 452                                 the SIGKILL signal. See
 453                                 <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 454                                 for more
 455                                 information.</para></listitem>
 456                         </varlistentry>
 457
 458                         <varlistentry>
 459                                 <term><varname>NonBlocking=</varname></term>
 460                                 <listitem><para>Set O_NONBLOCK flag
 461                                 for all file descriptors passed via
 462                                 socket-based activation. If true, all
 463                                 file descriptors >= 3 (i.e. all except
 464                                 STDIN/STDOUT/STDERR) will have
 465                                 the O_NONBLOCK flag set and hence are in
 466                                 non-blocking mode. This option is only
 467                                 useful in conjunction with a socket
 468                                 unit, as described in
 469                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
 470                                 to false.</para></listitem>
 471                         </varlistentry>
 472
 473                         <varlistentry>
 474                                 <term><varname>NotifyAccess=</varname></term>
 475                                 <listitem><para>Controls access to the
 476                                 service status notification socket, as
 477                                 accessible via the
 478                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 479                                 call. Takes one of
 480                                 <option>none</option> (the default),
 481                                 <option>main</option> or
 482                                 <option>all</option>. If
 483                                 <option>none</option> no daemon status
 484                                 updates are accepted by the service
 485                                 processes, all status update messages
 486                                 are ignored. If <option>main</option>
 487                                 only service updates sent from the
 488                                 main process of the service are
 489                                 accepted. If <option>all</option> all
 490                                 services updates from all members of
 491                                 the service's control group are
 492                                 accepted. This option must be set to
 493                                 open access to the notification socket
 494                                 when using
 495                                 <varname>Type=notify</varname> (see above).</para></listitem>
 496                         </varlistentry>
 497
 498                 </variablelist>
 499         </refsect1>
 500
 501         <refsect1>
 502                   <title>See Also</title>
 503                   <para>
 504                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 505                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 506                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 507                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 508                   </para>
 509         </refsect1>
 510
 511 </refentry>