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