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                 <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 [Unit] and [Install] sections. The
  68                 service specific configuration options are configured
  69                 in the [Service] section.</para>
  70
  71                 <para>Additional options are listed in
  72                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  73                 which define the execution environment the commands
  74                 are executed in.</para>
  75         </refsect1>
  76
  77         <refsect1>
  78                 <title>Options</title>
  79
  80                 <para>Service files must include a [Service] section,
  81                 which carries information about the service and the
  82                 process it supervises. A number of options that may be
  83                 used in this section are shared with other unit
  84                 types. These options are documented in
  85                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
  86                 options specific to the [Service] section of service
  87                 units are the following:</para>
  88
  89                 <variablelist>
  90                         <varlistentry>
  91                                 <term><varname>Type=</varname></term>
  92
  93                                 <listitem><para>Configures the process
  94                                 start-up type for this service
  95                                 unit. One of <option>simple</option>,
  96                                 <option>forking</option>,
  97                                 <option>finish</option>,
  98                                 <option>dbus</option>,
  99                                 <option>notify</option>.</para>
 100
 101                                 <para>If set to
 102                                 <option>simple</option> (the default
 103                                 value) it is expected that the process
 104                                 configured with
 105                                 <varname>ExecStart=</varname> is the
 106                                 main process of the service. In this
 107                                 mode, communication channels must be
 108                                 installed before the daemon is started
 109                                 up (e.g. sockets set up by systemd,
 110                                 via socket activation), as systemd
 111                                 will immediately proceed starting
 112                                 follow-up units.</para>
 113
 114                                 <para>If set to
 115                                 <option>forking</option> it is
 116                                 expected that the process configured
 117                                 with <varname>ExecStart=</varname>
 118                                 will start up and call
 119                                 <function>fork()</function>. The
 120                                 parent process is expected to finish
 121                                 when start-up is complete and all
 122                                 communication channels set up. The
 123                                 child continues to run as the main
 124                                 daemon process. This is the behaviour
 125                                 of traditional UNIX daemons. If this
 126                                 setting is used, it is recommended to
 127                                 also use the
 128                                 <varname>PIDFile=</varname> option, so
 129                                 that systemd can identify the main
 130                                 process of the daemon. systemd will
 131                                 proceed starting follow-up units as
 132                                 soon as the parent process
 133                                 exits.</para>
 134
 135                                 <para>Behaviour of
 136                                 <option>finish</option> is similar
 137                                 to <option>simple</option>, however
 138                                 it is expected that the process has to
 139                                 exit before systemd starts follow-up
 140                                 units. <varname>ValidNoProcess=</varname>
 141                                 is particularly useful for this type
 142                                 of service.</para>
 143
 144                                 <para>Behaviour of
 145                                 <option>dbus</option> is similar to
 146                                 <option>simple</option>, however it
 147                                 is expected that the daemon acquires a
 148                                 name on the D-Bus bus, as configured
 149                                 by
 150                                 <varname>BusName=</varname>. systemd
 151                                 will proceed starting follow-up units
 152                                 after the D-Bus bus name has been
 153                                 acquired.</para>
 154
 155                                 <para>Behaviour of
 156                                 <option>notify</option> is similar to
 157                                 <option>simple</option>, however it is
 158                                 expected that the daemon sends a
 159                                 notification message via
 160                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 161                                 or an equivalent call when it finished
 162                                 starting up. systemd will proceed
 163                                 starting follow-up units after this
 164                                 notification message has been sent. If
 165                                 this option is used
 166                                 <option>NotifyAccess=</option> (see
 167                                 below) must be set to open access to
 168                                 the notification socket provided by
 169                                 systemd.</para>
 170                                 </listitem>
 171                         </varlistentry>
 172
 173                         <varlistentry>
 174                                 <term><varname>ValidNoProcess=</varname></term>
 175
 176                                 <listitem><para>Takes a boolean value
 177                                 that specifies whether the service
 178                                 shall be considered active even when
 179                                 all its processes exited. Defaults to
 180                                 <option>no</option>.</para>
 181                                 </listitem>
 182                         </varlistentry>
 183
 184                         <varlistentry>
 185                                 <term><varname>PIDFile=</varname></term>
 186
 187                                 <listitem><para>Takes an absolute file
 188                                 name pointing to the PID file of this
 189                                 daemon. Use of this option is
 190                                 recommended for services where
 191                                 <varname>Type=</varname> is set to
 192                                 <option>forking</option>.</para>
 193                                 </listitem>
 194                         </varlistentry>
 195
 196                         <varlistentry>
 197                                 <term><varname>BusName=</varname></term>
 198
 199                                 <listitem><para>Takes a D-Bus bus
 200                                 name, where this service is reachable
 201                                 as. This option is mandatory for
 202                                 services where
 203                                 <varname>Type=</varname> is set to
 204                                 <option>dbus</option>, but its use
 205                                 is otherwise recommended as well if
 206                                 the process takes a name on the D-Bus
 207                                 bus.</para>
 208                                 </listitem>
 209                         </varlistentry>
 210
 211                         <varlistentry>
 212                                 <term><varname>ExecStart=</varname></term>
 213                                 <listitem><para>Takes a command line
 214                                 that is executed when this service
 215                                 shall be started up. The first token
 216                                 of the command line must be an
 217                                 absolute file name, then followed by
 218                                 arguments for the process. It is
 219                                 mandatory to set this option for all
 220                                 services. This option may not be
 221                                 specified more than once. Optionally,
 222                                 if the absolute file name is prefixed
 223                                 with @, the second token will be
 224                                 passed as argv[0] to the executed
 225                                 process, followed by the further
 226                                 arguments specified. Unless
 227                                 <option>Type=forking</option> is set,
 228                                 the process started via this command
 229                                 line will be considered the main
 230                                 process of the
 231                                 daemon.</para></listitem>
 232                         </varlistentry>
 233
 234                         <varlistentry>
 235                                 <term><varname>ExecStartPre=</varname></term>
 236                                 <term><varname>ExecStartPost=</varname></term>
 237                                 <listitem><para>Additional commands
 238                                 that are executed before (resp. after)
 239                                 the command in
 240                                 <varname>ExecStart=</varname>. If
 241                                 specified more than once, all commands
 242                                 are executed one after the other,
 243                                 serially. Use of these settings is
 244                                 optional.</para></listitem>
 245                         </varlistentry>
 246
 247                         <varlistentry>
 248                                 <term><varname>ExecReload=</varname></term>
 249                                 <listitem><para>Commands to execute to
 250                                 trigger a configuration reload in the
 251                                 service. If used more than once, all
 252                                 commands are executed one after the
 253                                 other, serially. Use of this setting is optional.
 254                                 </para></listitem>
 255                         </varlistentry>
 256
 257                         <varlistentry>
 258                                 <term><varname>ExecStop=</varname></term>
 259                                 <listitem><para>Commands to execute to
 260                                 stop the service started via
 261                                 <varname>ExecStart=</varname>. If used
 262                                 more than once, all commands are
 263                                 executed one after the other,
 264                                 serially. Use of this setting is
 265                                 optional. All processes remaining for
 266                                 a service after the commands
 267                                 configured in this option are run are
 268                                 terminated according to the
 269                                 <varname>KillMode=</varname> setting
 270                                 (see below). If this option is not
 271                                 specified the process is terminated
 272                                 right-away when service stop is
 273                                 requested.</para></listitem>
 274                         </varlistentry>
 275
 276                         <varlistentry>
 277                                 <term><varname>ExecStopPost=</varname></term>
 278                                 <listitem><para>Additional commands
 279                                 that are executed after the service
 280                                 was stopped using the commands
 281                                 configured in
 282                                 <varname>ExecStop=</varname>. If
 283                                 specified more than once, all commands
 284                                 are executed one after the other,
 285                                 serially. Use of these settings is
 286                                 optional.</para></listitem>
 287                         </varlistentry>
 288
 289                         <varlistentry>
 290                                 <term><varname>RestartSec=</varname></term>
 291                                 <listitem><para>Configures the time to
 292                                 sleep before restarting a service (as
 293                                 configured with
 294                                 <varname>Restart=</varname>). Takes a
 295                                 unit-less value in seconds, or a time
 296                                 span value such as "5min
 297                                 20s". Defaults to
 298                                 100ms.</para></listitem>
 299                         </varlistentry>
 300
 301                         <varlistentry>
 302                                 <term><varname>TimeoutSec=</varname></term>
 303                                 <listitem><para>Configures the time to
 304                                 wait for start-up and stop. If a
 305                                 daemon service does not signal
 306                                 start-up completion within the
 307                                 configured time the service will be
 308                                 considered failed and be shut down
 309                                 again. If a service is asked to stop
 310                                 but does not terminate in the
 311                                 specified time it will be terminated
 312                                 forcibly via SIGTERM, and after
 313                                 another delay of this time with
 314                                 SIGKILL. (See
 315                                 <option>KillMode=</option>
 316                                 below.) Takes a unit-less value in seconds, or a
 317                                 time span value such as "5min
 318                                 20s". Pass 0 to disable the timeout
 319                                 logic. Defaults to
 320                                 60s.</para></listitem>
 321                         </varlistentry>
 322
 323                         <varlistentry>
 324                                 <term><varname>Restart=</varname></term>
 325                                 <listitem><para>Configures whether the
 326                                 main service process shall be restarted when
 327                                 it exists. Takes one of
 328                                 <option>once</option>,
 329                                 <option>restart-on-success</option> or
 330                                 <option>restart-always</option>. If
 331                                 set to <option>once</option> (the
 332                                 default) the service will not be
 333                                 restarted when it exits. If set to
 334                                 <option>restart-on-success</option> it
 335                                 will be restarted only when it exited
 336                                 cleanly, i.e. terminated with an exit
 337                                 code of 0. If set to
 338                                 <option>restart-always</option> the
 339                                 service will be restarted regardless
 340                                 whether it exited cleanly or not, or
 341                                 got terminated abnormally by a
 342                                 signal.</para></listitem>
 343                         </varlistentry>
 344
 345                         <varlistentry>
 346                                 <term><varname>PermissionsStartOnly=</varname></term>
 347                                 <listitem><para>Takes a boolean
 348                                 argument. If true, the permission
 349                                 related execution options as
 350                                 configured with
 351                                 <varname>User=</varname> and similar
 352                                 options (see
 353                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 354                                 for more information) are only applied
 355                                 to the process started with
 356                                 <varname>ExecStart=</varname>, and not
 357                                 to the various other
 358                                 <varname>ExecStartPre=</varname>,
 359                                 <varname>ExecStartPost=</varname>,
 360                                 <varname>ExecReload=</varname>,
 361                                 <varname>ExecStop=</varname>,
 362                                 <varname>ExecStopPost=</varname>
 363                                 commands. If false, the setting is
 364                                 applied to all configured commands the
 365                                 same way. Defaults to
 366                                 false.</para></listitem>
 367                         </varlistentry>
 368
 369                         <varlistentry>
 370                                 <term><varname>RootDirectoryStartOnly=</varname></term>
 371                                 <listitem><para>Takes a boolean
 372                                 argument. If true, the root directory
 373                                 as configured with the
 374                                 <varname>RootDirectory=</varname>
 375                                 option (see
 376                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 377                                 for more information) is only applied
 378                                 to the process started with
 379                                 <varname>ExecStart=</varname>, and not
 380                                 to the various other
 381                                 <varname>ExecStartPre=</varname>,
 382                                 <varname>ExecStartPost=</varname>,
 383                                 <varname>ExecReload=</varname>,
 384                                 <varname>ExecStop=</varname>,
 385                                 <varname>ExecStopPost=</varname>
 386                                 commands. If false, the setting is
 387                                 applied to all configured commands the
 388                                 same way. Defaults to
 389                                 false.</para></listitem>
 390                         </varlistentry>
 391
 392                         <varlistentry>
 393                                 <term><varname>SysVStartPriority=</varname></term>
 394                                 <listitem><para>Set the SysV start
 395                                 priority to use to order this service
 396                                 in relation to SysV services lacking
 397                                 LSB headers. This option is only
 398                                 necessary to fix ordering in relation
 399                                 to legacy SysV services, that have no
 400                                 ordering information encoded in the
 401                                 script headers. As such it should only
 402                                 be used as temporary compatibility
 403                                 option, and not be used in new unit
 404                                 files. Almost always it is a better
 405                                 choice to add explicit ordering
 406                                 directives via
 407                                 <varname>After=</varname> or
 408                                 <varname>Before=</varname>,
 409                                 instead. For more details see
 410                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
 411                                 used, pass an integer value in the
 412                                 range 0-99.</para></listitem>
 413                         </varlistentry>
 414
 415                         <varlistentry>
 416                                 <term><varname>KillMode=</varname></term>
 417                                 <listitem><para>Specifies how
 418                                 processes of this service shall be
 419                                 killed. One of
 420                                 <option>control-group</option>,
 421                                 <option>process-group</option>,
 422                                 <option>process</option>,
 423                                 <option>none</option>.</para>
 424
 425                                 <para>If set to
 426                                 <option>control-group</option> all
 427                                 remaining processes in the control
 428                                 group of this service will be
 429                                 terminated on service stop, after the
 430                                 stop command (as configured with
 431                                 <varname>ExecStop=</varname>) is
 432                                 executed. If set to
 433                                 <option>process-group</option> only
 434                                 the members of the process group of
 435                                 the main service process are
 436                                 killed. If set to
 437                                 <option>process</option> only the main
 438                                 process itself is killed. If set to
 439                                 <option>none</option> no process is
 440                                 killed. In this case only the stop
 441                                 command will be executed on service
 442                                 stop, but no process be killed
 443                                 otherwise. Processes remaining alive
 444                                 after stop are left in their control
 445                                 group and the control group continues
 446                                 to exist after stop unless it is
 447                                 empty. Defaults to
 448                                 <option>control-croup</option>.</para>
 449
 450                                 <para>Processes will first be
 451                                 terminated via SIGTERM. If then after
 452                                 a delay (configured via the
 453                                 <option>TimeoutSec=</option> option)
 454                                 processes still remain, the
 455                                 termination request is repeated with
 456                                 the SIGKILL signal. See
 457                                 <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 458                                 for more
 459                                 information.</para></listitem>
 460                         </varlistentry>
 461
 462                         <varlistentry>
 463                                 <term><varname>NonBlocking=</varname></term>
 464                                 <listitem><para>Set O_NONBLOCK flag
 465                                 for all file descriptors passed via
 466                                 socket-based activation. If true, all
 467                                 file descriptors >= 3 (i.e. all except
 468                                 STDIN/STDOUT/STDERR) will have
 469                                 the O_NONBLOCK flag set and hence are in
 470                                 non-blocking mode. This option is only
 471                                 useful in conjunction with a socket
 472                                 unit, as described in
 473                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
 474                                 to false.</para></listitem>
 475                         </varlistentry>
 476
 477                         <varlistentry>
 478                                 <term><varname>NotifyAccess=</varname></term>
 479                                 <listitem><para>Controls access to the
 480                                 service status notification socket, as
 481                                 accessible via the
 482                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 483                                 call. Takes one of
 484                                 <option>none</option> (the default),
 485                                 <option>main</option> or
 486                                 <option>all</option>. If
 487                                 <option>none</option> no daemon status
 488                                 updates are accepted by the service
 489                                 processes, all status update messages
 490                                 are ignored. If <option>main</option>
 491                                 only service updates sent from the
 492                                 main process of the service are
 493                                 accepted. If <option>all</option> all
 494                                 services updates from all members of
 495                                 the service's control group are
 496                                 accepted. This option must be set to
 497                                 open access to the notification socket
 498                                 when using
 499                                 <varname>Type=notify</varname> (see above).</para></listitem>
 500                         </varlistentry>
 501
 502                 </variablelist>
 503         </refsect1>
 504
 505         <refsect1>
 506                   <title>See Also</title>
 507                   <para>
 508                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 509                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 510                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 511                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 512                   </para>
 513         </refsect1>
 514
 515 </refentry>