| | 1 | <?xml version='1.0'?> <!--*-nxml-*--> |
| | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
| | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
| | 4 | |
| | 5 | <!-- |
| | 6 | This file is part of systemd. |
| | 7 | |
| | 8 | Copyright 2010 Lennart Poettering |
| | 9 | |
| | 10 | systemd is free software; you can redistribute it and/or modify it |
| | 11 | under the terms of the GNU General Public License as published by |
| | 12 | the Free Software Foundation; either version 2 of the License, or |
| | 13 | (at your option) any later version. |
| | 14 | |
| | 15 | systemd is distributed in the hope that it will be useful, but |
| | 16 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| | 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| | 18 | General Public License for more details. |
| | 19 | |
| | 20 | You should have received a copy of the GNU General Public License |
| | 21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| | 22 | --> |
| | 23 | |
| | 24 | <refentry id="systemd.unit"> |
| | 25 | |
| | 26 | <refentryinfo> |
| | 27 | <title>systemd.unit</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.unit</refentrytitle> |
| | 42 | <manvolnum>5</manvolnum> |
| | 43 | </refmeta> |
| | 44 | |
| | 45 | <refnamediv> |
| | 46 | <refname>systemd.unit</refname> |
| | 47 | <refpurpose>systemd unit configuration files</refpurpose> |
| | 48 | </refnamediv> |
| | 49 | |
| | 50 | <refsynopsisdiv> |
| | 51 | <para><filename>systemd.service</filename>, |
| | 52 | <filename>systemd.socket</filename>, |
| | 53 | <filename>systemd.device</filename>, |
| | 54 | <filename>systemd.mount</filename>, |
| | 55 | <filename>systemd.automount</filename>, |
| | 56 | <filename>systemd.swap</filename>, |
| | 57 | <filename>systemd.target</filename>, |
| | 58 | <filename>systemd.path</filename>, |
| | 59 | <filename>systemd.timer</filename>, |
| | 60 | <filename>systemd.snapshot</filename></para> |
| | 61 | </refsynopsisdiv> |
| | 62 | |
| | 63 | <refsect1> |
| | 64 | <title>Description</title> |
| | 65 | |
| | 66 | <para>A unit configuration file encodes information |
| | 67 | about a service, a socket, a device, a mount point, an |
| | 68 | automount point, a swap file or partition, a start-up |
| | 69 | target, a file system path or a timer controlled and |
| | 70 | supervised by |
| | 71 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>. The |
| | 72 | syntax is inspired by <ulink |
| | 73 | url="http://standards.freedesktop.org/desktop-entry-spec/latest/">XDG |
| | 74 | Desktop Entry Specification</ulink> <filename>.desktop</filename> files, which are in turn |
| | 75 | inspired by Microsoft Windows |
| | 76 | <filename>.ini</filename> files.</para> |
| | 77 | |
| | 78 | <para>This man pages lists the common configuration |
| | 79 | options of all the unit types. These options need to |
| | 80 | be configured in the [Unit] resp. [Install] |
| | 81 | section of the unit files.</para> |
| | 82 | |
| | 83 | <para>In addition to the generic [Unit] and [Install] |
| | 84 | sections described here, each unit should have a |
| | 85 | type-specific section, e.g. [Service] for a service |
| | 86 | unit. See the respective man pages for more |
| | 87 | information.</para> |
| | 88 | |
| | 89 | <para>Unit files may contain additional options on top |
| | 90 | of those listed here. If systemd encounters an unknown |
| | 91 | option it will write a warning log message but |
| | 92 | continue loading the unit. If an option is prefixed |
| | 93 | with <option>X-</option> it is ignored completely by |
| | 94 | systemd. Applications may use this to include |
| | 95 | additional information in the unit files.</para> |
| | 96 | |
| | 97 | <para>Boolean arguments used in unit files can be |
| | 98 | written in various formats. For positive settings the |
| | 99 | strings <option>1</option>, <option>yes</option>, |
| | 100 | <option>true</option> and <option>on</option> are |
| | 101 | equivalent. For negative settings the strings |
| | 102 | <option>0</option>, <option>no</option>, |
| | 103 | <option>false</option> and <option>off</option> are |
| | 104 | equivalent.</para> |
| | 105 | |
| | 106 | <para>Time span values encoded in unit files can be |
| | 107 | written in various formats. A stand-alone number |
| | 108 | specifies a time in seconds. If suffixed with a time |
| | 109 | unit, the unit is honored. A concatenation of |
| | 110 | multiple values with units is supported, in which case |
| | 111 | the values are added up. Example: "50" refers to 50 |
| | 112 | seconds; "2min 200ms" refers to 2 minutes plus 200 |
| | 113 | milliseconds, i.e. 120200ms. The following time units |
| | 114 | are understood: s, min, h, d, w, ms, us.</para> |
| | 115 | |
| | 116 | <para>Empty lines and lines starting with # or ; are |
| | 117 | ignored. This may be used for commenting. Lines ending |
| | 118 | in a backslash are concatenated with the following |
| | 119 | line while reading and the backslash is replaced by a |
| | 120 | space character. This may be used to wrap long lines.</para> |
| | 121 | |
| | 122 | <para>If a line starts with <option>.include</option> |
| | 123 | followed by a file name, the specified file will be |
| | 124 | read as if its contents were listed in place of the |
| | 125 | <option>.include</option> directive.</para> |
| | 126 | |
| | 127 | <para>Along with a unit file |
| | 128 | <filename>foo.service</filename> a directory |
| | 129 | <filename>foo.service.wants/</filename> may exist. All |
| | 130 | units symlinked from such a directory are implicitly |
| | 131 | added as dependencies of type |
| | 132 | <varname>Wanted=</varname> to the unit. This is useful |
| | 133 | to hook units into the start-up of other units, |
| | 134 | without having to modify their unit configuration |
| | 135 | files. For details about the semantics of |
| | 136 | <varname>Wanted=</varname> see below. The preferred |
| | 137 | way to create symlinks in the |
| | 138 | <filename>.wants/</filename> directory of a service is |
| | 139 | with the <command>enable</command> command of the |
| | 140 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| | 141 | tool which reads information from the [Install] |
| | 142 | section of unit files. (See below.) A similar |
| | 143 | functionality exists for <varname>Requires=</varname> |
| | 144 | type dependencies as well, the directory suffix is |
| | 145 | <filename>.requires/</filename> in this case.</para> |
| | 146 | |
| | 147 | <para>Note that while systemd offers a flexible |
| | 148 | dependency system between units it is recommended to |
| | 149 | use this functionality only sparsely and instead rely |
| | 150 | on techniques such as bus-based or socket-based |
| | 151 | activation which makes dependencies implicit, which |
| | 152 | both results in a simpler and more flexible |
| | 153 | system.</para> |
| | 154 | |
| | 155 | <para>Some unit names reflect paths existing in the |
| | 156 | file system name space. Example: a device unit |
| | 157 | <filename>dev-sda.device</filename> refers to a device |
| | 158 | with the device node <filename>/dev/sda</filename> in |
| | 159 | the file system namespace. If this applies a special |
| | 160 | way to escape the path name is used, so that the |
| | 161 | result is usable as part of a file name. Basically, |
| | 162 | given a path, "/" is replaced by "-", and all |
| | 163 | unprintable characters and the "-" are replaced by |
| | 164 | C-style "\x20" escapes. The root directory "/" is |
| | 165 | encoded as single dash, while otherwise the initial |
| | 166 | and ending "/" is removed from all paths during |
| | 167 | transformation. This escaping is reversible.</para> |
| | 168 | |
| | 169 | <para>Optionally, units may be instantiated from a |
| | 170 | template file at runtime. This allows creation of |
| | 171 | multiple units from a single configuration file. If |
| | 172 | systemd looks for a unit configuration file it will |
| | 173 | first search for the literal unit name in the |
| | 174 | filesystem. If that yields no success and the unit |
| | 175 | name contains an @ character, systemd will look for a |
| | 176 | unit template that shares the same name but with the |
| | 177 | instance string (i.e. the part between the @ character |
| | 178 | and the suffix) removed. Example: if a service |
| | 179 | <filename>getty@tty3.service</filename> is requested |
| | 180 | and no file by that name is found, systemd will look |
| | 181 | for <filename>getty@.service</filename> and |
| | 182 | instantiate a service from that configuration file if |
| | 183 | it is found.</para> |
| | 184 | |
| | 185 | <para>To refer to the instance string from |
| | 186 | within the configuration file you may use the special |
| | 187 | <literal>%i</literal> specifier in many of the |
| | 188 | configuration options. Other specifiers exist, the |
| | 189 | full list is:</para> |
| | 190 | |
| | 191 | <table> |
| | 192 | <title>Specifiers available in unit files</title> |
| | 193 | <tgroup cols='3' align='left' colsep='1' rowsep='1'> |
| | 194 | <colspec colname="spec" /> |
| | 195 | <colspec colname="mean" /> |
| | 196 | <colspec colname="detail" /> |
| | 197 | <thead> |
| | 198 | <row> |
| | 199 | <entry>Specifier</entry> |
| | 200 | <entry>Meaning</entry> |
| | 201 | <entry>Details</entry> |
| | 202 | </row> |
| | 203 | </thead> |
| | 204 | <tbody> |
| | 205 | <row> |
| | 206 | <entry><literal>%n</literal></entry> |
| | 207 | <entry>Full unit name</entry> |
| | 208 | <entry></entry> |
| | 209 | </row> |
| | 210 | <row> |
| | 211 | <entry><literal>%N</literal></entry> |
| | 212 | <entry>Unescaped full unit name</entry> |
| | 213 | <entry></entry> |
| | 214 | </row> |
| | 215 | <row> |
| | 216 | <entry><literal>%p</literal></entry> |
| | 217 | <entry>Prefix name</entry> |
| | 218 | <entry>This refers to the string before the @, i.e. "getty" in the example above, where "tty3" is the instance name.</entry> |
| | 219 | </row> |
| | 220 | <row> |
| | 221 | <entry><literal>%P</literal></entry> |
| | 222 | <entry>Unescaped prefix name</entry> |
| | 223 | <entry></entry> |
| | 224 | </row> |
| | 225 | <row> |
| | 226 | <entry><literal>%i</literal></entry> |
| | 227 | <entry>Instance name</entry> |
| | 228 | <entry>This is the string between the @ character and the suffix.</entry> |
| | 229 | </row> |
| | 230 | <row> |
| | 231 | <entry><literal>%I</literal></entry> |
| | 232 | <entry>Unescaped instance name</entry> |
| | 233 | <entry></entry> |
| | 234 | </row> |
| | 235 | <row> |
| | 236 | <entry><literal>%f</literal></entry> |
| | 237 | <entry>Unescaped file name</entry> |
| | 238 | <entry>This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /.</entry> |
| | 239 | </row> |
| | 240 | <row> |
| | 241 | <entry><literal>%c</literal></entry> |
| | 242 | <entry>Control group path of the unit</entry> |
| | 243 | <entry></entry> |
| | 244 | </row> |
| | 245 | <row> |
| | 246 | <entry><literal>%r</literal></entry> |
| | 247 | <entry>Root control group path of systemd</entry> |
| | 248 | <entry></entry> |
| | 249 | </row> |
| | 250 | <row> |
| | 251 | <entry><literal>%R</literal></entry> |
| | 252 | <entry>Parent directory of the root control group path of systemd</entry> |
| | 253 | <entry></entry> |
| | 254 | </row> |
| | 255 | <row> |
| | 256 | <entry><literal>%t</literal></entry> |
| | 257 | <entry>Runtime socket dir</entry> |
| | 258 | <entry>This is either /run (for the system manager) or $XDG_RUNTIME_DIR (for user managers).</entry> |
| | 259 | </row> |
| | 260 | </tbody> |
| | 261 | </tgroup> |
| | 262 | </table> |
| | 263 | |
| | 264 | <para>If a unit file is empty (i.e. has the file size |
| | 265 | 0) or is symlinked to <filename>/dev/null</filename> |
| | 266 | its configuration will not be loaded and it appears |
| | 267 | with a load state of <literal>masked</literal>, and |
| | 268 | cannot be activated. Use this as an effective way to |
| | 269 | fully disable a unit, making it impossible to start it |
| | 270 | even manually.</para> |
| | 271 | |
| | 272 | <para>The unit file format is covered by the |
| | 273 | <ulink |
| | 274 | url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface |
| | 275 | Stability Promise</ulink>.</para> |
| | 276 | </refsect1> |
| | 277 | |
| | 278 | <refsect1> |
| | 279 | <title>Options</title> |
| | 280 | |
| | 281 | <para>Unit file may include a [Unit] section, which |
| | 282 | carries generic information about the unit that is not |
| | 283 | dependent on the type of unit:</para> |
| | 284 | |
| | 285 | <variablelist> |
| | 286 | |
| | 287 | <varlistentry> |
| | 288 | <term><varname>Description=</varname></term> |
| | 289 | <listitem><para>A free-form string |
| | 290 | describing the unit. This is intended |
| | 291 | for use in UIs to show descriptive |
| | 292 | information along with the unit |
| | 293 | name.</para></listitem> |
| | 294 | </varlistentry> |
| | 295 | |
| | 296 | <varlistentry> |
| | 297 | <term><varname>Requires=</varname></term> |
| | 298 | |
| | 299 | <listitem><para>Configures requirement |
| | 300 | dependencies on other units. If this |
| | 301 | unit gets activated, the units listed |
| | 302 | here will be activated as well. If one |
| | 303 | of the other units gets deactivated or |
| | 304 | its activation fails, this unit will |
| | 305 | be deactivated. This option may be |
| | 306 | specified more than once, in which |
| | 307 | case requirement dependencies for all |
| | 308 | listed names are created. Note that |
| | 309 | requirement dependencies do not |
| | 310 | influence the order in which services |
| | 311 | are started or stopped. This has to be |
| | 312 | configured independently with the |
| | 313 | <varname>After=</varname> or |
| | 314 | <varname>Before=</varname> options. If |
| | 315 | a unit |
| | 316 | <filename>foo.service</filename> |
| | 317 | requires a unit |
| | 318 | <filename>bar.service</filename> as |
| | 319 | configured with |
| | 320 | <varname>Requires=</varname> and no |
| | 321 | ordering is configured with |
| | 322 | <varname>After=</varname> or |
| | 323 | <varname>Before=</varname>, then both |
| | 324 | units will be started simultaneously |
| | 325 | and without any delay between them if |
| | 326 | <filename>foo.service</filename> is |
| | 327 | activated. Often it is a better choice |
| | 328 | to use <varname>Wants=</varname> |
| | 329 | instead of |
| | 330 | <varname>Requires=</varname> in order |
| | 331 | to achieve a system that is more |
| | 332 | robust when dealing with failing |
| | 333 | services.</para></listitem> |
| | 334 | </varlistentry> |
| | 335 | |
| | 336 | <varlistentry> |
| | 337 | <term><varname>RequiresOverridable=</varname></term> |
| | 338 | |
| | 339 | <listitem><para>Similar to |
| | 340 | <varname>Requires=</varname>. |
| | 341 | Dependencies listed in |
| | 342 | <varname>RequiresOverridable=</varname> |
| | 343 | which cannot be fulfilled or fail to |
| | 344 | start are ignored if the startup was |
| | 345 | explicitly requested by the user. If |
| | 346 | the start-up was pulled in indirectly |
| | 347 | by some dependency or automatic |
| | 348 | start-up of units that is not |
| | 349 | requested by the user this dependency |
| | 350 | must be fulfilled and otherwise the |
| | 351 | transaction fails. Hence, this option |
| | 352 | may be used to configure dependencies |
| | 353 | that are normally honored unless the |
| | 354 | user explicitly starts up the unit, in |
| | 355 | which case whether they failed or not |
| | 356 | is irrelevant.</para></listitem> |
| | 357 | |
| | 358 | </varlistentry> |
| | 359 | <varlistentry> |
| | 360 | <term><varname>Requisite=</varname></term> |
| | 361 | <term><varname>RequisiteOverridable=</varname></term> |
| | 362 | |
| | 363 | <listitem><para>Similar to |
| | 364 | <varname>Requires=</varname> |
| | 365 | resp. <varname>RequiresOverridable=</varname>. However, |
| | 366 | if a unit listed here is not started |
| | 367 | already it will not be started and the |
| | 368 | transaction fails |
| | 369 | immediately.</para></listitem> |
| | 370 | </varlistentry> |
| | 371 | |
| | 372 | <varlistentry> |
| | 373 | <term><varname>Wants=</varname></term> |
| | 374 | |
| | 375 | <listitem><para>A weaker version of |
| | 376 | <varname>Requires=</varname>. A unit |
| | 377 | listed in this option will be started |
| | 378 | if the configuring unit is. However, |
| | 379 | if the listed unit fails to start up |
| | 380 | or cannot be added to the transaction |
| | 381 | this has no impact on the validity of |
| | 382 | the transaction as a whole. This is |
| | 383 | the recommended way to hook start-up |
| | 384 | of one unit to the start-up of another |
| | 385 | unit. Note that dependencies of this |
| | 386 | type may also be configured outside of |
| | 387 | the unit configuration file by |
| | 388 | adding a symlink to a |
| | 389 | <filename>.wants/</filename> directory |
| | 390 | accompanying the unit file. For |
| | 391 | details see above.</para></listitem> |
| | 392 | </varlistentry> |
| | 393 | |
| | 394 | <varlistentry> |
| | 395 | <term><varname>BindTo=</varname></term> |
| | 396 | |
| | 397 | <listitem><para>Configures requirement |
| | 398 | dependencies, very similar in style to |
| | 399 | <varname>Requires=</varname>, however |
| | 400 | in addition to this behaviour it also |
| | 401 | declares that this unit is stopped |
| | 402 | when any of the units listed suddenly |
| | 403 | disappears. Units can suddenly, |
| | 404 | unexpectedly disappear if a service |
| | 405 | terminates on its own choice, a device |
| | 406 | is unplugged or a mount point |
| | 407 | unmounted without involvement of |
| | 408 | systemd.</para></listitem> |
| | 409 | </varlistentry> |
| | 410 | |
| | 411 | <varlistentry> |
| | 412 | <term><varname>Conflicts=</varname></term> |
| | 413 | |
| | 414 | <listitem><para>Configures negative |
| | 415 | requirement dependencies. If a unit |
| | 416 | has a |
| | 417 | <varname>Conflicts=</varname> setting |
| | 418 | on another unit, starting the former |
| | 419 | will stop the latter and vice |
| | 420 | versa. Note that this setting is |
| | 421 | independent of and orthogonal to the |
| | 422 | <varname>After=</varname> and |
| | 423 | <varname>Before=</varname> ordering |
| | 424 | dependencies.</para> |
| | 425 | |
| | 426 | <para>If a unit A that conflicts with |
| | 427 | a unit B is scheduled to be started at |
| | 428 | the same time as B, the transaction |
| | 429 | will either fail (in case both are |
| | 430 | required part of the transaction) or |
| | 431 | be modified to be fixed (in case one |
| | 432 | or both jobs are not a required part |
| | 433 | of the transaction). In the latter |
| | 434 | case the job that is not the required |
| | 435 | will be removed, or in case both are |
| | 436 | not required the unit that conflicts |
| | 437 | will be started and the unit that is |
| | 438 | conflicted is |
| | 439 | stopped.</para></listitem> |
| | 440 | </varlistentry> |
| | 441 | |
| | 442 | <varlistentry> |
| | 443 | <term><varname>Before=</varname></term> |
| | 444 | <term><varname>After=</varname></term> |
| | 445 | |
| | 446 | <listitem><para>Configures ordering |
| | 447 | dependencies between units. If a unit |
| | 448 | <filename>foo.service</filename> |
| | 449 | contains a setting |
| | 450 | <option>Before=bar.service</option> |
| | 451 | and both units are being started, |
| | 452 | <filename>bar.service</filename>'s |
| | 453 | start-up is delayed until |
| | 454 | <filename>foo.service</filename> is |
| | 455 | started up. Note that this setting is |
| | 456 | independent of and orthogonal to the |
| | 457 | requirement dependencies as configured |
| | 458 | by <varname>Requires=</varname>. It is |
| | 459 | a common pattern to include a unit |
| | 460 | name in both the |
| | 461 | <varname>After=</varname> and |
| | 462 | <varname>Requires=</varname> option in |
| | 463 | which case the unit listed will be |
| | 464 | started before the unit that is |
| | 465 | configured with these options. This |
| | 466 | option may be specified more than |
| | 467 | once, in which case ordering |
| | 468 | dependencies for all listed names are |
| | 469 | created. <varname>After=</varname> is |
| | 470 | the inverse of |
| | 471 | <varname>Before=</varname>, i.e. while |
| | 472 | <varname>After=</varname> ensures that |
| | 473 | the configured unit is started after |
| | 474 | the listed unit finished starting up, |
| | 475 | <varname>Before=</varname> ensures the |
| | 476 | opposite, i.e. that the configured |
| | 477 | unit is fully started up before the |
| | 478 | listed unit is started. Note that when |
| | 479 | two units with an ordering dependency |
| | 480 | between them are shut down, the |
| | 481 | inverse of the start-up order is |
| | 482 | applied. i.e. if a unit is configured |
| | 483 | with <varname>After=</varname> on |
| | 484 | another unit, the former is stopped |
| | 485 | before the latter if both are shut |
| | 486 | down. If one unit with an ordering |
| | 487 | dependency on another unit is shut |
| | 488 | down while the latter is started up, |
| | 489 | the shut down is ordered before the |
| | 490 | start-up regardless whether the |
| | 491 | ordering dependency is actually of |
| | 492 | type <varname>After=</varname> or |
| | 493 | <varname>Before=</varname>. If two |
| | 494 | units have no ordering dependencies |
| | 495 | between them they are shut down |
| | 496 | resp. started up simultaneously, and |
| | 497 | no ordering takes |
| | 498 | place. </para></listitem> |
| | 499 | </varlistentry> |
| | 500 | |
| | 501 | <varlistentry> |
| | 502 | <term><varname>OnFailure=</varname></term> |
| | 503 | |
| | 504 | <listitem><para>Lists one or more |
| | 505 | units that are activated when this |
| | 506 | unit enters the |
| | 507 | '<literal>failed</literal>' |
| | 508 | state.</para></listitem> |
| | 509 | </varlistentry> |
| | 510 | |
| | 511 | <varlistentry> |
| | 512 | <term><varname>OnFailureIsolate=</varname></term> |
| | 513 | |
| | 514 | <listitem><para>Takes a boolean |
| | 515 | argument. If <option>true</option> the |
| | 516 | unit listed in |
| | 517 | <varname>OnFailure=</varname> will be |
| | 518 | enqueued in isolation mode, i.e. all |
| | 519 | units that are not its dependency will |
| | 520 | be stopped. If this is set only a |
| | 521 | single unit may be listed in |
| | 522 | <varname>OnFailure=</varname>. Defaults |
| | 523 | to |
| | 524 | <option>false</option>.</para></listitem> |
| | 525 | </varlistentry> |
| | 526 | |
| | 527 | <varlistentry> |
| | 528 | <term><varname>IgnoreOnIsolate=</varname></term> |
| | 529 | |
| | 530 | <listitem><para>Takes a boolean |
| | 531 | argument. If <option>true</option> |
| | 532 | this unit will not be stopped when |
| | 533 | isolating another unit. Defaults to |
| | 534 | <option>false</option>.</para></listitem> |
| | 535 | </varlistentry> |
| | 536 | |
| | 537 | <varlistentry> |
| | 538 | <term><varname>IgnoreOnSnapshot=</varname></term> |
| | 539 | |
| | 540 | <listitem><para>Takes a boolean |
| | 541 | argument. If <option>true</option> |
| | 542 | this unit will not be included in |
| | 543 | snapshots. Defaults to |
| | 544 | <option>true</option> for device and |
| | 545 | snapshot units, <option>false</option> |
| | 546 | for the others.</para></listitem> |
| | 547 | </varlistentry> |
| | 548 | |
| | 549 | <varlistentry> |
| | 550 | <term><varname>StopWhenUnneeded=</varname></term> |
| | 551 | |
| | 552 | <listitem><para>Takes a boolean |
| | 553 | argument. If <option>true</option> |
| | 554 | this unit will be stopped when it is |
| | 555 | no longer used. Note that in order to |
| | 556 | minimize the work to be executed, |
| | 557 | systemd will not stop units by default |
| | 558 | unless they are conflicting with other |
| | 559 | units, or the user explicitly |
| | 560 | requested their shut down. If this |
| | 561 | option is set, a unit will be |
| | 562 | automatically cleaned up if no other |
| | 563 | active unit requires it. Defaults to |
| | 564 | <option>false</option>.</para></listitem> |
| | 565 | </varlistentry> |
| | 566 | |
| | 567 | <varlistentry> |
| | 568 | <term><varname>RefuseManualStart=</varname></term> |
| | 569 | <term><varname>RefuseManualStop=</varname></term> |
| | 570 | |
| | 571 | <listitem><para>Takes a boolean |
| | 572 | argument. If <option>true</option> |
| | 573 | this unit can only be activated |
| | 574 | (resp. deactivated) indirectly. In |
| | 575 | this case explicit start-up |
| | 576 | (resp. termination) requested by the |
| | 577 | user is denied, however if it is |
| | 578 | started (resp. stopped) as a |
| | 579 | dependency of another unit, start-up |
| | 580 | (resp. termination) will succeed. This |
| | 581 | is mostly a safety feature to ensure |
| | 582 | that the user does not accidentally |
| | 583 | activate units that are not intended |
| | 584 | to be activated explicitly, and not |
| | 585 | accidentally deactivate units that are |
| | 586 | not intended to be deactivated. |
| | 587 | These options default to |
| | 588 | <option>false</option>.</para></listitem> |
| | 589 | </varlistentry> |
| | 590 | |
| | 591 | <varlistentry> |
| | 592 | <term><varname>AllowIsolate=</varname></term> |
| | 593 | |
| | 594 | <listitem><para>Takes a boolean |
| | 595 | argument. If <option>true</option> |
| | 596 | this unit may be used with the |
| | 597 | <command>systemctl isolate</command> |
| | 598 | command. Otherwise this will be |
| | 599 | refused. It probably is a good idea to |
| | 600 | leave this disabled except for target |
| | 601 | units that shall be used similar to |
| | 602 | runlevels in SysV init systems, just |
| | 603 | as a precaution to avoid unusable |
| | 604 | system states. This option defaults to |
| | 605 | <option>false</option>.</para></listitem> |
| | 606 | </varlistentry> |
| | 607 | |
| | 608 | <varlistentry> |
| | 609 | <term><varname>DefaultDependencies=</varname></term> |
| | 610 | |
| | 611 | <listitem><para>Takes a boolean |
| | 612 | argument. If <option>true</option> |
| | 613 | (the default), a few default |
| | 614 | dependencies will implicitly be |
| | 615 | created for the unit. The actual |
| | 616 | dependencies created depend on the |
| | 617 | unit type. For example, for service |
| | 618 | units, these dependencies ensure that |
| | 619 | the service is started only after |
| | 620 | basic system initialization is |
| | 621 | completed and is properly terminated on |
| | 622 | system shutdown. See the respective |
| | 623 | man pages for details. Generally, only |
| | 624 | services involved with early boot or |
| | 625 | late shutdown should set this option |
| | 626 | to <option>false</option>. It is |
| | 627 | highly recommended to leave this |
| | 628 | option enabled for the majority of |
| | 629 | common units. If set to |
| | 630 | <option>false</option> this option |
| | 631 | does not disable all implicit |
| | 632 | dependencies, just non-essential |
| | 633 | ones.</para></listitem> |
| | 634 | </varlistentry> |
| | 635 | |
| | 636 | <varlistentry> |
| | 637 | <term><varname>JobTimeoutSec=</varname></term> |
| | 638 | |
| | 639 | <listitem><para>When clients are |
| | 640 | waiting for a job of this unit to |
| | 641 | complete, time out after the specified |
| | 642 | time. If this time limit is reached |
| | 643 | the job will be cancelled, the unit |
| | 644 | however will not change state or even |
| | 645 | enter the '<literal>failed</literal>' |
| | 646 | mode. This value defaults to 0 (job |
| | 647 | timeouts disabled), except for device |
| | 648 | units. NB: this timeout is independent |
| | 649 | from any unit-specific timeout (for |
| | 650 | example, the timeout set with |
| | 651 | <varname>Timeout=</varname> in service |
| | 652 | units) as the job timeout has no |
| | 653 | effect on the unit itself, only on the |
| | 654 | job that might be pending for it. Or |
| | 655 | in other words: unit-specific timeouts |
| | 656 | are useful to abort unit state |
| | 657 | changes, and revert them. The job |
| | 658 | timeout set with this option however |
| | 659 | is useful to abort only the job |
| | 660 | waiting for the unit state to |
| | 661 | change.</para></listitem> |
| | 662 | </varlistentry> |
| | 663 | |
| | 664 | <varlistentry> |
| | 665 | <term><varname>ConditionPathExists=</varname></term> |
| | 666 | <term><varname>ConditionPathExistsGlob=</varname></term> |
| | 667 | <term><varname>ConditionPathIsDirectory=</varname></term> |
| | 668 | <term><varname>ConditionDirectoryNotEmpty=</varname></term> |
| | 669 | <term><varname>ConditionFileIsExecutable=</varname></term> |
| | 670 | <term><varname>ConditionKernelCommandLine=</varname></term> |
| | 671 | <term><varname>ConditionVirtualization=</varname></term> |
| | 672 | <term><varname>ConditionSecurity=</varname></term> |
| | 673 | <term><varname>ConditionNull=</varname></term> |
| | 674 | |
| | 675 | <listitem><para>Before starting a unit |
| | 676 | verify that the specified condition is |
| | 677 | true. With |
| | 678 | <varname>ConditionPathExists=</varname> |
| | 679 | a file existence condition can be |
| | 680 | checked before a unit is started. If |
| | 681 | the specified absolute path name does |
| | 682 | not exist startup of a unit will not |
| | 683 | actually happen, however the unit is |
| | 684 | still useful for ordering purposes in |
| | 685 | this case. The condition is checked at |
| | 686 | the time the queued start job is to be |
| | 687 | executed. If the absolute path name |
| | 688 | passed to |
| | 689 | <varname>ConditionPathExists=</varname> |
| | 690 | is prefixed with an exclamation mark |
| | 691 | (!), the test is negated, and the unit |
| | 692 | only started if the path does not |
| | 693 | exist. <varname>ConditionPathExistsGlob=</varname> |
| | 694 | work in a similar way, but checks for |
| | 695 | the existance of at least one file or |
| | 696 | directory matching the specified |
| | 697 | globbing |
| | 698 | pattern. <varname>ConditionPathIsDirectory=</varname> |
| | 699 | is similar to |
| | 700 | <varname>ConditionPathExists=</varname> |
| | 701 | but verifies whether a certain path |
| | 702 | exists and is a |
| | 703 | directory. <varname>ConditionFileIsExecutable=</varname> |
| | 704 | is similar to |
| | 705 | <varname>ConditionPathExists=</varname> |
| | 706 | but verifies whether a certain path |
| | 707 | exists, is a regular file and marked |
| | 708 | executable. |
| | 709 | <varname>ConditionDirectoryNotEmpty=</varname> |
| | 710 | is similar to |
| | 711 | <varname>ConditionPathExists=</varname> |
| | 712 | but verifies whether a certain path |
| | 713 | exists and is a non-empty |
| | 714 | directory. Similarly |
| | 715 | <varname>ConditionKernelCommandLine=</varname> |
| | 716 | may be used to check whether a |
| | 717 | specific kernel command line option is |
| | 718 | set (or if prefixed with the |
| | 719 | exclamation mark unset). The argument |
| | 720 | must either be a single word, or an |
| | 721 | assignment (i.e. two words, separated |
| | 722 | by the equality sign). In the former |
| | 723 | case the kernel command line is |
| | 724 | searched for the word appearing as is, |
| | 725 | or as left hand side of an |
| | 726 | assignment. In the latter case the |
| | 727 | exact assignment is looked for with |
| | 728 | right and left hand side |
| | 729 | matching. <varname>ConditionVirtualization=</varname> |
| | 730 | may be used to check whether the |
| | 731 | system is executed in a virtualized |
| | 732 | environment and optionally test |
| | 733 | whether it is a specific |
| | 734 | implementation. Takes either boolean |
| | 735 | value to check if being executed in |
| | 736 | any virtual environment or one of the |
| | 737 | <varname>qemu</varname>, |
| | 738 | <varname>kvm</varname>, |
| | 739 | <varname>vmware</varname>, |
| | 740 | <varname>microsoft</varname>, |
| | 741 | <varname>oracle</varname>, |
| | 742 | <varname>xen</varname>, |
| | 743 | <varname>pidns</varname>, |
| | 744 | <varname>openvz</varname> to test |
| | 745 | against a specific implementation. The |
| | 746 | test may be negated by prepending an |
| | 747 | exclamation mark. |
| | 748 | <varname>ConditionSecurity=</varname> |
| | 749 | may be used to check whether the given |
| | 750 | security module is enabled on the |
| | 751 | system. Currently the only recognized |
| | 752 | value is <varname>selinux</varname>. |
| | 753 | The test may be negated by prepending |
| | 754 | an exclamation mark. Finally, |
| | 755 | <varname>ConditionNull=</varname> may |
| | 756 | be used to add a constant condition |
| | 757 | check value to the unit. It takes a |
| | 758 | boolean argument. If set to |
| | 759 | <varname>false</varname> the condition |
| | 760 | will always fail, otherwise |
| | 761 | succeed. If multiple conditions are |
| | 762 | specified the unit will be executed if |
| | 763 | all of them apply (i.e. a logical AND |
| | 764 | is applied). Condition checks can be |
| | 765 | prefixed with a pipe symbol (|) in |
| | 766 | which case a condition becomes a |
| | 767 | triggering condition. If at least one |
| | 768 | triggering condition is defined for a |
| | 769 | unit then the unit will be executed if |
| | 770 | at least one of the triggering |
| | 771 | conditions apply and all of the |
| | 772 | non-triggering conditions. If you |
| | 773 | prefix an argument with the pipe |
| | 774 | symbol and an exclamation mark the |
| | 775 | pipe symbol must be passed first, the |
| | 776 | exclamation second.</para></listitem> |
| | 777 | </varlistentry> |
| | 778 | |
| | 779 | <varlistentry> |
| | 780 | <term><varname>Names=</varname></term> |
| | 781 | |
| | 782 | <listitem><para>Additional names for |
| | 783 | this unit. The names listed here must |
| | 784 | have the same suffix (i.e. type) as |
| | 785 | the unit file name. This option may be |
| | 786 | specified more than once, in which |
| | 787 | case all listed names are used. Note |
| | 788 | that this option is different from the |
| | 789 | <varname>Alias=</varname> option from |
| | 790 | the [Install] section mentioned |
| | 791 | below. See below for details. Note |
| | 792 | that in almost all cases this option |
| | 793 | is not what you want. A symlink alias |
| | 794 | in the file system is generally |
| | 795 | preferable since it can be used as |
| | 796 | lookup key. If a unit with a symlinked |
| | 797 | alias name is not loaded and needs to |
| | 798 | be it is easily found via the |
| | 799 | symlink. However, if a unit with an |
| | 800 | alias name configured with this |
| | 801 | setting is not loaded it will not be |
| | 802 | discovered. This settings' only use is |
| | 803 | in conjunction with service |
| | 804 | instances.</para> |
| | 805 | </listitem> |
| | 806 | </varlistentry> |
| | 807 | </variablelist> |
| | 808 | |
| | 809 | <para>Unit file may include a [Install] section, which |
| | 810 | carries installation information for the unit. This |
| | 811 | section is not interpreted by |
| | 812 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| | 813 | during runtime. It is used exclusively by the |
| | 814 | <command>enable</command> and |
| | 815 | <command>disable</command> commands of the |
| | 816 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| | 817 | tool during installation of a unit:</para> |
| | 818 | |
| | 819 | <variablelist> |
| | 820 | <varlistentry> |
| | 821 | <term><varname>Alias=</varname></term> |
| | 822 | |
| | 823 | <listitem><para>Additional names this |
| | 824 | unit shall be installed under. The |
| | 825 | names listed here must have the same |
| | 826 | suffix (i.e. type) as the unit file |
| | 827 | name. This option may be specified |
| | 828 | more than once, in which case all |
| | 829 | listed names are used. At installation |
| | 830 | time, |
| | 831 | <command>systemctl enable</command> |
| | 832 | will create symlinks from these names |
| | 833 | to the unit file name. Note that this |
| | 834 | is different from the |
| | 835 | <varname>Names=</varname> option from |
| | 836 | the [Unit] section mentioned above: |
| | 837 | The names from |
| | 838 | <varname>Names=</varname> apply |
| | 839 | unconditionally if the unit is |
| | 840 | loaded. The names from |
| | 841 | <varname>Alias=</varname> apply only |
| | 842 | if the unit has actually been |
| | 843 | installed with the |
| | 844 | <command>systemctl enable</command> |
| | 845 | command. Also, if systemd searches for a |
| | 846 | unit, it will discover symlinked alias |
| | 847 | names as configured with |
| | 848 | <varname>Alias=</varname>, but not |
| | 849 | names configured with |
| | 850 | <varname>Names=</varname> only. It is |
| | 851 | a common pattern to list a name in |
| | 852 | both options. In this case, a unit |
| | 853 | will be active under all names if |
| | 854 | installed, but also if not installed |
| | 855 | but requested explicitly under its |
| | 856 | main name.</para></listitem> |
| | 857 | </varlistentry> |
| | 858 | |
| | 859 | <varlistentry> |
| | 860 | <term><varname>WantedBy=</varname></term> |
| | 861 | |
| | 862 | <listitem><para>Installs a symlink in |
| | 863 | the <filename>.wants/</filename> |
| | 864 | subdirectory for a unit. This has the |
| | 865 | effect that when the listed unit name |
| | 866 | is activated the unit listing it is |
| | 867 | activated |
| | 868 | too. <command>WantedBy=foo.service</command> |
| | 869 | in a service |
| | 870 | <filename>bar.service</filename> is |
| | 871 | mostly equivalent to |
| | 872 | <command>Alias=foo.service.wants/bar.service</command> |
| | 873 | in the same file.</para></listitem> |
| | 874 | </varlistentry> |
| | 875 | |
| | 876 | <varlistentry> |
| | 877 | <term><varname>Also=</varname></term> |
| | 878 | |
| | 879 | <listitem><para>Additional units to |
| | 880 | install when this unit is |
| | 881 | installed. If the user requests |
| | 882 | installation of a unit with this |
| | 883 | option configured, |
| | 884 | <command>systemctl enable</command> |
| | 885 | will automatically install units |
| | 886 | listed in this option as |
| | 887 | well.</para></listitem> |
| | 888 | </varlistentry> |
| | 889 | </variablelist> |
| | 890 | |
| | 891 | </refsect1> |
| | 892 | |
| | 893 | <refsect1> |
| | 894 | <title>See Also</title> |
| | 895 | <para> |
| | 896 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| | 897 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| | 898 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| | 899 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 900 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 901 | <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 902 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 903 | <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 904 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 905 | <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 906 | <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 907 | <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| | 908 | <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
| | 909 | </para> |
| | 910 | </refsect1> |
| | 911 | |
| | 912 | </refentry> |
projects / thirdparty / systemd.git / blame_incremental