2 .TH "SYSTEMD\&.UNIT" "5" "" "systemd 220" "systemd.unit"
3 .\" -----------------------------------------------------------------
4 .\" * Define some portability stuff
5 .\" -----------------------------------------------------------------
6 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
7 .\" http://bugs.debian.org/507673
8 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
9 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12 .\" -----------------------------------------------------------------
13 .\" * set default formatting
14 .\" -----------------------------------------------------------------
15 .\" disable hyphenation
17 .\" disable justification (adjust text to left margin only)
19 .\" -----------------------------------------------------------------
20 .\" * MAIN CONTENT STARTS HERE *
21 .\" -----------------------------------------------------------------
23 systemd.unit \- Unit configuration
26 \fIservice\fR\&.service,
27 \fIsocket\fR\&.socket,
28 \fIdevice\fR\&.device,
30 \fIautomount\fR\&.automount,
32 \fItarget\fR\&.target,
35 \fIsnapshot\fR\&.snapshot,
42 /usr/lib/systemd/system/*
48 $XDG_CONFIG_HOME/systemd/user/*
49 $HOME/\&.config/systemd/user/*
51 $XDG_RUNTIME_DIR/systemd/user/*
53 $XDG_DATA_HOME/systemd/user/*
54 $HOME/\&.local/share/systemd/user/*
55 /usr/lib/systemd/user/*
61 A unit configuration file encodes information about a service, a socket, a device, a mount point, an automount point, a swap file or partition, a start\-up target, a watched file system path, a timer controlled and supervised by
62 \fBsystemd\fR(1), a temporary system state snapshot, a resource management slice or a group of externally created processes\&. The syntax is inspired by
63 \m[blue]\fBXDG Desktop Entry Specification\fR\m[]\&\s-2\u[1]\d\s+2\&.desktop
64 files, which are in turn inspired by Microsoft Windows
68 This man page lists the common configuration options of all the unit types\&. These options need to be configured in the [Unit] or [Install] sections of the unit files\&.
70 In addition to the generic [Unit] and [Install] sections described here, each unit may have a type\-specific section, e\&.g\&. [Service] for a service unit\&. See the respective man pages for more information:
71 \fBsystemd.service\fR(5),
72 \fBsystemd.socket\fR(5),
73 \fBsystemd.device\fR(5),
74 \fBsystemd.mount\fR(5),
75 \fBsystemd.automount\fR(5),
76 \fBsystemd.swap\fR(5),
77 \fBsystemd.target\fR(5),
78 \fBsystemd.path\fR(5),
79 \fBsystemd.timer\fR(5),
80 \fBsystemd.snapshot\fR(5)\&.
81 \fBsystemd.slice\fR(5)\&.
82 \fBsystemd.scope\fR(5)\&.
84 Various settings are allowed to be specified more than once, in which case the interpretation depends on the setting\&. Often, multiple settings form a list, and setting to an empty value "resets", which means that previous assignments are ignored\&. When this is allowed, it is mentioned in the description of the setting\&. Note that using multiple assignments to the same value makes the unit file incompatible with parsers for the XDG
88 Unit files are loaded from a set of paths determined during compilation, described in the next section\&.
90 Unit files may contain additional options on top of those listed here\&. If systemd encounters an unknown option, it will write a warning log message but continue loading the unit\&. If an option or section name is prefixed with
91 \fBX\-\fR, it is ignored completely by systemd\&. Options within an ignored section do not need the prefix\&. Applications may use this to include additional information in the unit files\&.
93 Boolean arguments used in unit files can be written in various formats\&. For positive settings the strings
99 are equivalent\&. For negative settings, the strings
107 Time span values encoded in unit files can be written in various formats\&. A stand\-alone number specifies a time in seconds\&. If suffixed with a time unit, the unit is honored\&. A concatenation of multiple values with units is supported, in which case the values are added up\&. Example: "50" refers to 50 seconds; "2min 200ms" refers to 2 minutes plus 200 milliseconds, i\&.e\&. 120200ms\&. The following time units are understood: s, min, h, d, w, ms, us\&. For details see
108 \fBsystemd.time\fR(7)\&.
110 Empty lines and lines starting with # or ; are ignored\&. This may be used for commenting\&. Lines ending in a backslash are concatenated with the following line while reading and the backslash is replaced by a space character\&. This may be used to wrap long lines\&.
112 Along with a unit file
113 foo\&.service, the directory
114 foo\&.service\&.wants/
115 may exist\&. All unit files symlinked from such a directory are implicitly added as dependencies of type
117 to the unit\&. This is useful to hook units into the start\-up of other units, without having to modify their unit files\&. For details about the semantics of
118 \fIWants=\fR, see below\&. The preferred way to create symlinks in the
120 directory of a unit file is with the
124 tool which reads information from the [Install] section of unit files (see below)\&. A similar functionality exists for
126 type dependencies as well, the directory suffix is
130 Along with a unit file
131 foo\&.service, a directory
133 may exist\&. All files with the suffix
135 from this directory will be parsed after the file itself is parsed\&. This is useful to alter or add configuration settings to a unit, without having to modify their unit files\&. Make sure that the file that is included has the appropriate section headers before any directive\&. Note that for instanced units this logic will first look for the instance
137 subdirectory and read its
139 files, followed by the template
141 subdirectory and reads its
145 Note that while systemd offers a flexible dependency system between units it is recommended to use this functionality only sparingly and instead rely on techniques such as bus\-based or socket\-based activation which make dependencies implicit, resulting in a both simpler and more flexible system\&.
147 Some unit names reflect paths existing in the file system namespace\&. Example: a device unit
149 refers to a device with the device node
151 in the file system namespace\&. If this applies, a special way to escape the path name is used, so that the result is usable as part of a filename\&. Basically, given a path, "/" is replaced by "\-" and all other characters which are not ASCII alphanumerics are replaced by C\-style "\ex2d" escapes (except that "_" is never replaced and "\&." is only replaced when it would be the first character in the escaped path)\&. The root directory "/" is encoded as single dash, while otherwise the initial and ending "/" are removed from all paths during transformation\&. This escaping is reversible\&. Properly escaped paths can be generated using the
152 \fBsystemd-escape\fR(1)
155 Optionally, units may be instantiated from a template file at runtime\&. This allows creation of multiple units from a single configuration file\&. If systemd looks for a unit configuration file, it will first search for the literal unit name in the file system\&. If that yields no success and the unit name contains an
157 character, systemd will look for a unit template that shares the same name but with the instance string (i\&.e\&. the part between the
159 character and the suffix) removed\&. Example: if a service
161 is requested and no file by that name is found, systemd will look for
163 and instantiate a service from that configuration file if it is found\&.
165 To refer to the instance string from within the configuration file you may use the special
167 specifier in many of the configuration options\&. See below for details\&.
169 If a unit file is empty (i\&.e\&. has the file size 0) or is symlinked to
170 /dev/null, its configuration will not be loaded and it appears with a load state of
171 "masked", and cannot be activated\&. Use this as an effective way to fully disable a unit, making it impossible to start it even manually\&.
173 The unit file format is covered by the
174 \m[blue]\fBInterface Stability Promise\fR\m[]\&\s-2\u[2]\d\s+2\&.
177 Unit files are loaded from a set of paths determined during compilation, described in the two tables below\&. Unit files found in directories listed earlier override files with the same name in directories lower in the list\&.
179 When systemd is running in user mode (\fB\-\-user\fR) and the variable
180 \fI$SYSTEMD_UNIT_PATH\fR
181 is set, the contents of this variable overrides the unit load path\&. If
182 \fI$SYSTEMD_UNIT_PATH\fR
183 ends with an empty component (":"), the usual unit load path will be appended to the contents of the variable\&.
186 .nr an-no-space-flag 1
189 .B Table\ \&1.\ \& Load path when running in system mode (\-\-system).
213 /usr/lib/systemd/system
215 Units of installed packages
221 .nr an-no-space-flag 1
224 .B Table\ \&2.\ \& Load path when running in user mode (\-\-user).
243 $XDG_CONFIG_HOME/systemd/user
245 User configuration (only used when $XDG_CONFIG_HOME is set)
248 $HOME/\&.config/systemd/user
250 User configuration (only used when $XDG_CONFIG_HOME is not set)
258 $XDG_RUNTIME_DIR/systemd/user
260 Runtime units (only used when $XDG_RUNTIME_DIR is set)
268 $XDG_DATA_HOME/systemd/user
270 Units of packages that have been installed in the home directory (only used when $XDG_DATA_HOME is set)
273 $HOME/\&.local/share/systemd/user
275 Units of packages that have been installed in the home directory (only used when $XDG_DATA_HOME is not set)
278 /usr/lib/systemd/user
280 Units of packages that have been installed system\-wide
285 Additional units might be loaded into systemd ("linked") from directories not on the unit load path\&. See the
288 \fBsystemctl\fR(1)\&. Also, some units are dynamically created via a
289 \fBsystemd.generator\fR(7)\&.
290 .SH "[UNIT] SECTION OPTIONS"
292 Unit file may include a [Unit] section, which carries generic information about the unit that is not dependent on the type of unit:
296 A free\-form string describing the unit\&. This is intended for use in UIs to show descriptive information along with the unit name\&. The description should contain a name that means something to the end user\&.
298 is a good example\&. Bad examples are
299 "high\-performance light\-weight HTTP server"
302 (too specific and meaningless for people who do not know Apache)\&.
307 A space\-separated list of URIs referencing documentation for this unit or its configuration\&. Accepted are only URIs of the types
312 "man:"\&. For more information about the syntax of these URIs, see
313 \fBuri\fR(7)\&. The URIs should be listed in order of relevance, starting with the most relevant\&. It is a good idea to first reference documentation that explains what the unit\*(Aqs purpose is, followed by how it is configured, followed by any other related documentation\&. This option may be specified more than once, in which case the specified list of URIs is merged\&. If the empty string is assigned to this option, the list is reset and all prior assignments will have no effect\&.
318 Configures requirement dependencies on other units\&. If this unit gets activated, the units listed here will be activated as well\&. If one of the other units gets deactivated or its activation fails, this unit will be deactivated\&. This option may be specified more than once or multiple space\-separated units may be specified in one option in which case requirement dependencies for all listed names will be created\&. Note that requirement dependencies do not influence the order in which services are started or stopped\&. This has to be configured independently with the
328 and no ordering is configured with
331 \fIBefore=\fR, then both units will be started simultaneously and without any delay between them if
333 is activated\&. Often it is a better choice to use
337 in order to achieve a system that is more robust when dealing with failing services\&.
339 Note that dependencies of this type may also be configured outside of the unit configuration file by adding a symlink to a
341 directory accompanying the unit file\&. For details see above\&.
344 \fIRequiresOverridable=\fR
347 \fIRequires=\fR\&. Dependencies listed in
348 \fIRequiresOverridable=\fR
349 which cannot be fulfilled or fail to start are ignored if the startup was explicitly requested by the user\&. If the start\-up was pulled in indirectly by some dependency or automatic start\-up of units that is not requested by the user, this dependency must be fulfilled and otherwise the transaction fails\&. Hence, this option may be used to configure dependencies that are normally honored unless the user explicitly starts up the unit, in which case whether they failed or not is irrelevant\&.
352 \fIRequisite=\fR, \fIRequisiteOverridable=\fR
357 \fIRequiresOverridable=\fR, respectively\&. However, if the units listed here are not started already, they will not be started and the transaction will fail immediately\&.
363 \fIRequires=\fR\&. Units listed in this option will be started if the configuring unit is\&. However, if the listed units fail to start or cannot be added to the transaction, this has no impact on the validity of the transaction as a whole\&. This is the recommended way to hook start\-up of one unit to the start\-up of another unit\&.
365 Note that dependencies of this type may also be configured outside of the unit configuration file by adding symlinks to a
367 directory accompanying the unit file\&. For details, see above\&.
372 Configures requirement dependencies, very similar in style to
373 \fIRequires=\fR, however in addition to this behavior, it also declares that this unit is stopped when any of the units listed suddenly disappears\&. Units can suddenly, unexpectedly disappear if a service terminates on its own choice, a device is unplugged or a mount point unmounted without involvement of systemd\&.
378 Configures dependencies similar to
379 \fIRequires=\fR, but limited to stopping and restarting of units\&. When systemd stops or restarts the units listed here, the action is propagated to this unit\&. Note that this is a one\-way dependency\ \&\(em changes to this unit do not affect the listed units\&.
384 A space\-separated list of unit names\&. Configures negative requirement dependencies\&. If a unit has a
386 setting on another unit, starting the former will stop the latter and vice versa\&. Note that this setting is independent of and orthogonal to the
390 ordering dependencies\&.
392 If a unit A that conflicts with a unit B is scheduled to be started at the same time as B, the transaction will either fail (in case both are required part of the transaction) or be modified to be fixed (in case one or both jobs are not a required part of the transaction)\&. In the latter case, the job that is not the required will be removed, or in case both are not required, the unit that conflicts will be started and the unit that is conflicted is stopped\&.
395 \fIBefore=\fR, \fIAfter=\fR
397 A space\-separated list of unit names\&. Configures ordering dependencies between units\&. If a unit
400 \fBBefore=bar\&.service\fR
401 and both units are being started,
402 bar\&.service\*(Aqs start\-up is delayed until
404 is started up\&. Note that this setting is independent of and orthogonal to the requirement dependencies as configured by
405 \fIRequires=\fR\&. It is a common pattern to include a unit name in both the
409 option, in which case the unit listed will be started before the unit that is configured with these options\&. This option may be specified more than once, in which case ordering dependencies for all listed names are created\&.
412 \fIBefore=\fR, i\&.e\&. while
414 ensures that the configured unit is started after the listed unit finished starting up,
416 ensures the opposite, i\&.e\&. that the configured unit is fully started up before the listed unit is started\&. Note that when two units with an ordering dependency between them are shut down, the inverse of the start\-up order is applied\&. i\&.e\&. if a unit is configured with
418 on another unit, the former is stopped before the latter if both are shut down\&. If one unit with an ordering dependency on another unit is shut down while the latter is started up, the shut down is ordered before the start\-up regardless of whether the ordering dependency is actually of type
421 \fIBefore=\fR\&. If two units have no ordering dependencies between them, they are shut down or started up simultaneously, and no ordering takes place\&.
426 A space\-separated list of one or more units that are activated when this unit enters the
431 \fIPropagatesReloadTo=\fR, \fIReloadPropagatedFrom=\fR
433 A space\-separated list of one or more units where reload requests on this unit will be propagated to, or reload requests on the other unit will be propagated to this unit, respectively\&. Issuing a reload request on a unit will automatically also enqueue a reload request on all units that the reload request shall be propagated to via these two settings\&.
436 \fIJoinsNamespaceOf=\fR
438 For units that start processes (such as service units), lists one or more other units whose network and/or temporary file namespace to join\&. This only applies to unit types which support the
439 \fIPrivateNetwork=\fR
443 \fBsystemd.exec\fR(5)
444 for details)\&. If a unit that has this setting set is started, its processes will see the same
447 and network namespace as one listed unit that is started\&. If multiple listed units are already started, it is not defined which namespace is joined\&. Note that this setting only has an effect if
448 \fIPrivateNetwork=\fR
451 is enabled for both the unit that joins the namespace and the unit whose namespace is joined\&.
454 \fIRequiresMountsFor=\fR
456 Takes a space\-separated list of absolute paths\&. Automatically adds dependencies of type
460 for all mount units required to access the specified path\&.
462 Mount points marked with
464 are not mounted automatically and will be ignored for the purposes of this option\&. If such a mount should be a requirement for this unit, direct dependencies on the mount units may be added (\fIRequires=\fR
467 or some other combination)\&.
470 \fIOnFailureJobMode=\fR
475 "replace\-irreversibly",
478 "ignore\-dependencies"
480 "ignore\-requirements"\&. Defaults to
481 "replace"\&. Specifies how the units listed in
483 will be enqueued\&. See
484 \fBsystemctl\fR(1)\*(Aqs
486 option for details on the possible values\&. If this is set to
487 "isolate", only a single unit may be listed in
488 \fIOnFailure=\fR\&.\&.
491 \fIIgnoreOnIsolate=\fR
493 Takes a boolean argument\&. If
494 \fBtrue\fR, this unit will not be stopped when isolating another unit\&. Defaults to
498 \fIIgnoreOnSnapshot=\fR
500 Takes a boolean argument\&. If
501 \fBtrue\fR, this unit will not be included in snapshots\&. Defaults to
503 for device and snapshot units,
508 \fIStopWhenUnneeded=\fR
510 Takes a boolean argument\&. If
511 \fBtrue\fR, this unit will be stopped when it is no longer used\&. Note that in order to minimize the work to be executed, systemd will not stop units by default unless they are conflicting with other units, or the user explicitly requested their shut down\&. If this option is set, a unit will be automatically cleaned up if no other active unit requires it\&. Defaults to
515 \fIRefuseManualStart=\fR, \fIRefuseManualStop=\fR
517 Takes a boolean argument\&. If
518 \fBtrue\fR, this unit can only be activated or deactivated indirectly\&. In this case, explicit start\-up or termination requested by the user is denied, however if it is started or stopped as a dependency of another unit, start\-up or termination will succeed\&. This is mostly a safety feature to ensure that the user does not accidentally activate units that are not intended to be activated explicitly, and not accidentally deactivate units that are not intended to be deactivated\&. These options default to
524 Takes a boolean argument\&. If
525 \fBtrue\fR, this unit may be used with the
526 \fBsystemctl isolate\fR
527 command\&. Otherwise, this will be refused\&. It probably is a good idea to leave this disabled except for target units that shall be used similar to runlevels in SysV init systems, just as a precaution to avoid unusable system states\&. This option defaults to
531 \fIDefaultDependencies=\fR
533 Takes a boolean argument\&. If
534 \fBtrue\fR, (the default), a few default dependencies will implicitly be created for the unit\&. The actual dependencies created depend on the unit type\&. For example, for service units, these dependencies ensure that the service is started only after basic system initialization is completed and is properly terminated on system shutdown\&. See the respective man pages for details\&. Generally, only services involved with early boot or late shutdown should set this option to
535 \fBfalse\fR\&. It is highly recommended to leave this option enabled for the majority of common units\&. If set to
536 \fBfalse\fR, this option does not disable all implicit dependencies, just non\-essential ones\&.
539 \fIJobTimeoutSec=\fR, \fIJobTimeoutAction=\fR, \fIJobTimeoutRebootArgument=\fR
541 When a job for this unit is queued a time\-out may be configured\&. If this time limit is reached, the job will be cancelled, the unit however will not change state or even enter the
543 mode\&. This value defaults to 0 (job timeouts disabled), except for device units\&. NB: this timeout is independent from any unit\-specific timeout (for example, the timeout set with
544 \fIStartTimeoutSec=\fR
545 in service units) as the job timeout has no effect on the unit itself, only on the job that might be pending for it\&. Or in other words: unit\-specific timeouts are useful to abort unit state changes, and revert them\&. The job timeout set with this option however is useful to abort only the job waiting for the unit state to change\&.
547 \fIJobTimeoutAction=\fR
548 optionally configures an additional action to take when the time\-out is hit\&. It takes the same values as the per\-service
549 \fIStartLimitAction=\fR
551 \fBsystemd.service\fR(5)
552 for details\&. Defaults to
554 \fIJobTimeoutRebootArgument=\fR
555 configures an optional reboot string to pass to the
560 \fIConditionArchitecture=\fR, \fIConditionVirtualization=\fR, \fIConditionHost=\fR, \fIConditionKernelCommandLine=\fR, \fIConditionSecurity=\fR, \fIConditionCapability=\fR, \fIConditionACPower=\fR, \fIConditionNeedsUpdate=\fR, \fIConditionFirstBoot=\fR, \fIConditionPathExists=\fR, \fIConditionPathExistsGlob=\fR, \fIConditionPathIsDirectory=\fR, \fIConditionPathIsSymbolicLink=\fR, \fIConditionPathIsMountPoint=\fR, \fIConditionPathIsReadWrite=\fR, \fIConditionDirectoryNotEmpty=\fR, \fIConditionFileNotEmpty=\fR, \fIConditionFileIsExecutable=\fR
562 Before starting a unit verify that the specified condition is true\&. If it is not true, the starting of the unit will be skipped, however all ordering dependencies of it are still respected\&. A failing condition will not result in the unit being moved into a failure state\&. The condition is checked at the time the queued start job is to be executed\&.
564 \fIConditionArchitecture=\fR
565 may be used to check whether the system is running on a specific architecture\&. Takes one of
593 to test against a specific architecture\&. The architecture is determined from the information returned by
595 and is thus subject to
596 \fBpersonality\fR(2)\&. Note that a
598 setting in the same unit file has no effect on this condition\&. A special architecture name
600 is mapped to the architecture the system manager itself is compiled for\&. The test may be negated by prepending an exclamation mark\&.
602 \fIConditionVirtualization=\fR
603 may be used to check whether the system is executed in a virtualized environment and optionally test whether it is a specific implementation\&. Takes either boolean value to check if being executed in any virtualized environment, or one of
607 to test against a generic type of virtualization solution, or one of
620 \fIsystemd\-nspawn\fR,
622 to test against a specific implementation\&. See
623 \fBsystemd-detect-virt\fR(1)
624 for a full list of known virtualization technologies and their identifiers\&. If multiple virtualization technologies are nested, only the innermost is considered\&. The test may be negated by prepending an exclamation mark\&.
627 may be used to match against the hostname or machine ID of the host\&. This either takes a hostname string (optionally with shell style globs) which is tested against the locally set hostname as returned by
628 \fBgethostname\fR(2), or a machine ID formatted as string (see
629 \fBmachine-id\fR(5))\&. The test may be negated by prepending an exclamation mark\&.
631 \fIConditionKernelCommandLine=\fR
632 may be used to check whether a specific kernel command line option is set (or if prefixed with the exclamation mark unset)\&. The argument must either be a single word, or an assignment (i\&.e\&. two words, separated
633 "=")\&. In the former case the kernel command line is searched for the word appearing as is, or as left hand side of an assignment\&. In the latter case, the exact assignment is looked for with right and left hand side matching\&.
635 \fIConditionSecurity=\fR
636 may be used to check whether the given security module is enabled on the system\&. Currently the recognized values values are
642 \fIaudit\fR\&. The test may be negated by prepending an exclamation mark\&.
644 \fIConditionCapability=\fR
645 may be used to check whether the given capability exists in the capability bounding set of the service manager (i\&.e\&. this does not check whether capability is actually available in the permitted or effective sets, see
646 \fBcapabilities\fR(7)
647 for details)\&. Pass a capability name such as
648 "CAP_MKNOD", possibly prefixed with an exclamation mark to negate the check\&.
650 \fIConditionACPower=\fR
651 may be used to check whether the system has AC power, or is exclusively battery powered at the time of activation of the unit\&. This takes a boolean argument\&. If set to
652 \fItrue\fR, the condition will hold only if at least one AC connector of the system is connected to a power source, or if no AC connectors are known\&. Conversely, if set to
653 \fIfalse\fR, the condition will hold only if there is at least one AC connector known and all AC connectors are disconnected from a power source\&.
655 \fIConditionNeedsUpdate=\fR
660 as argument, possibly prefixed with a
662 (for inverting the condition)\&. This condition may be used to conditionalize units on whether the specified directory requires an update because
663 /usr\*(Aqs modification time is newer than the stamp file
665 in the specified directory\&. This is useful to implement offline updates of the vendor operating system resources in
667 that require updating of
671 on the next following boot\&. Units making use of this condition should order themselves before
672 \fBsystemd-update-done.service\fR(8), to make sure they run before the stamp files\*(Aqs modification time gets reset indicating a completed update\&.
674 \fIConditionFirstBoot=\fR
675 takes a boolean argument\&. This condition may be used to conditionalize units on whether the system is booting up with an unpopulated
677 directory\&. This may be used to populate
679 on the first boot after factory reset, or when a new system instances boots up for the first time\&.
682 \fIConditionPathExists=\fR
683 a file existence condition is checked before a unit is started\&. If the specified absolute path name does not exist, the condition will fail\&. If the absolute path name passed to
684 \fIConditionPathExists=\fR
685 is prefixed with an exclamation mark ("!"), the test is negated, and the unit is only started if the path does not exist\&.
687 \fIConditionPathExistsGlob=\fR
689 \fIConditionPathExists=\fR, but checks for the existence of at least one file or directory matching the specified globbing pattern\&.
691 \fIConditionPathIsDirectory=\fR
693 \fIConditionPathExists=\fR
694 but verifies whether a certain path exists and is a directory\&.
696 \fIConditionPathIsSymbolicLink=\fR
698 \fIConditionPathExists=\fR
699 but verifies whether a certain path exists and is a symbolic link\&.
701 \fIConditionPathIsMountPoint=\fR
703 \fIConditionPathExists=\fR
704 but verifies whether a certain path exists and is a mount point\&.
706 \fIConditionPathIsReadWrite=\fR
708 \fIConditionPathExists=\fR
709 but verifies whether the underlying file system is readable and writable (i\&.e\&. not mounted read\-only)\&.
711 \fIConditionDirectoryNotEmpty=\fR
713 \fIConditionPathExists=\fR
714 but verifies whether a certain path exists and is a non\-empty directory\&.
716 \fIConditionFileNotEmpty=\fR
718 \fIConditionPathExists=\fR
719 but verifies whether a certain path exists and refers to a regular file with a non\-zero size\&.
721 \fIConditionFileIsExecutable=\fR
723 \fIConditionPathExists=\fR
724 but verifies whether a certain path exists, is a regular file and marked executable\&.
726 If multiple conditions are specified, the unit will be executed if all of them apply (i\&.e\&. a logical AND is applied)\&. Condition checks can be prefixed with a pipe symbol (|) in which case a condition becomes a triggering condition\&. If at least one triggering condition is defined for a unit, then the unit will be executed if at least one of the triggering conditions apply and all of the non\-triggering conditions\&. If you prefix an argument with the pipe symbol and an exclamation mark, the pipe symbol must be passed first, the exclamation second\&. Except for
727 \fIConditionPathIsSymbolicLink=\fR, all path checks follow symlinks\&. If any of these options is assigned the empty string, the list of conditions is reset completely, all previous condition settings (of any kind) will have no effect\&.
730 \fIAssertArchitecture=\fR, \fIAssertVirtualization=\fR, \fIAssertHost=\fR, \fIAssertKernelCommandLine=\fR, \fIAssertSecurity=\fR, \fIAssertCapability=\fR, \fIAssertACPower=\fR, \fIAssertNeedsUpdate=\fR, \fIAssertFirstBoot=\fR, \fIAssertPathExists=\fR, \fIAssertPathExistsGlob=\fR, \fIAssertPathIsDirectory=\fR, \fIAssertPathIsSymbolicLink=\fR, \fIAssertPathIsMountPoint=\fR, \fIAssertPathIsReadWrite=\fR, \fIAssertDirectoryNotEmpty=\fR, \fIAssertFileNotEmpty=\fR, \fIAssertFileIsExecutable=\fR
733 \fIConditionArchitecture=\fR,
734 \fIConditionVirtualization=\fR, \&.\&.\&. condition settings described above these settings add assertion checks to the start\-up of the unit\&. However, unlike the conditions settings any assertion setting that is not met results in failure of the start job it was triggered by\&.
739 A path to a configuration file this unit has been generated from\&. This is primarily useful for implementation of generator tools that convert configuration from an external configuration file format into native unit files\&. This functionality should not be used in normal units\&.
741 .SH "[INSTALL] SECTION OPTIONS"
743 Unit file may include an
745 section, which carries installation information for the unit\&. This section is not interpreted by
747 during runtime\&. It is used exclusively by the
753 tool during installation of a unit:
757 A space\-separated list of additional names this unit shall be installed under\&. The names listed here must have the same suffix (i\&.e\&. type) as the unit file name\&. This option may be specified more than once, in which case all listed names are used\&. At installation time,
758 \fBsystemctl enable\fR
759 will create symlinks from these names to the unit filename\&.
762 \fIWantedBy=\fR, \fIRequiredBy=\fR
764 This option may be used more than once, or a space\-separated list of unit names may be given\&. A symbolic link is created in the
768 directory of each of the listed units when this unit is installed by
769 \fBsystemctl enable\fR\&. This has the effect that a dependency of type
773 is added from the listed unit to the current unit\&. The primary result is that the current unit will be started when the listed unit is started\&. See the description of
777 in the [Unit] section for details\&.
779 \fBWantedBy=foo\&.service\fR
782 is mostly equivalent to
783 \fBAlias=foo\&.service\&.wants/bar\&.service\fR
784 in the same file\&. In case of template units,
785 \fBsystemctl enable\fR
786 must be called with an instance name, and this instance will be added to the
790 list of the listed unit\&. E\&.g\&.
791 \fBWantedBy=getty\&.target\fR
795 \fBsystemctl enable getty@tty2\&.service\fR
797 getty\&.target\&.wants/getty@tty2\&.service
804 Additional units to install/deinstall when this unit is installed/deinstalled\&. If the user requests installation/deinstallation of a unit with this option configured,
805 \fBsystemctl enable\fR
807 \fBsystemctl disable\fR
808 will automatically install/uninstall units listed in this option as well\&.
810 This option may be used more than once, or a space\-separated list of unit names may be given\&.
813 \fIDefaultInstance=\fR
815 In template unit files, this specifies for which instance the unit shall be enabled if the template is enabled without any explicitly set instance\&. This option has no effect in non\-template unit files\&. The specified string must be usable as instance identifier\&.
818 The following specifiers are interpreted in the Install section: %n, %N, %p, %i, %U, %u, %m, %H, %b, %v\&. For their meaning see the next section\&.
821 Many settings resolve specifiers which may be used to write generic unit files referring to runtime or unit parameters that are replaced when the unit files are loaded\&. The following specifiers are understood:
824 .nr an-no-space-flag 1
827 .B Table\ \&3.\ \&Specifiers available in unit files
869 Unescaped full unit name
871 Same as "%n", but with escaping undone
878 For instantiated units, this refers to the string before the "@" character of the unit name\&. For non\-instantiated units, this refers to the name of the unit with the type suffix removed\&.
883 Unescaped prefix name
885 Same as "%p", but with escaping undone
892 For instantiated units: this is the string between the "@" character and the suffix of the unit name\&.
897 Unescaped instance name
899 Same as "%i", but with escaping undone
906 This is either the unescaped instance name (if applicable) with / prepended (if applicable), or the prefix name prepended with /\&.
911 Control group path of the unit
913 This path does not include the /sys/fs/cgroup/systemd/ prefix\&.
918 Control group path of the slice the unit is placed in
920 This usually maps to the parent cgroup path of "%c"\&.
925 Root control group path below which slices and units are placed
927 For system instances, this resolves to /, except in containers, where this maps to the container\*(Aqs root control group path\&.
934 This is either /run (for the system manager) or the path "$XDG_RUNTIME_DIR" resolves to (for user managers)\&.
941 This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance\&.
948 This is the numeric UID of the configured user of the unit, or (if none is set) the user running the systemd user instance\&. Note that this specifier is not available for units run by the systemd system instance (as opposed to those run by a systemd user instance), unless the user has been configured as a numeric UID in the first place or the configured user is the root user\&.
955 This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd user instance\&. Similar to "%U", this specifier is not available for units run by the systemd system instance, unless the configured user is the root user\&.
962 This is the shell of the configured user of the unit, or (if none is set) the user running the systemd user instance\&. Similar to "%U", this specifier is not available for units run by the systemd system instance, unless the configured user is the root user\&.
969 The machine ID of the running system, formatted as string\&. See \fBmachine-id\fR(5) for more information\&.
976 The boot ID of the running system, formatted as string\&. See \fBrandom\fR(4) for more information\&.
983 The hostname of the running system at the point in time the unit configuration is loaded\&.
990 Identical to \fBuname \-r\fR output
997 Use "%%" in place of "%" to specify a single percent sign\&.
1002 Please note that specifiers
1006 are mostly useless when systemd is running in system mode\&. PID 1 cannot query the user account database for information, so the specifiers only work as shortcuts for things which are already specified in a different way in the unit file\&. They are fully functional when systemd is running in
1011 \fBExample\ \&1.\ \&Allowing units to be enabled\fR
1013 The following snippet (highlighted) allows a unit (e\&.g\&.
1014 foo\&.service) to be enabled via
1015 \fBsystemctl enable\fR:
1025 ExecStart=/usr/sbin/foo\-daemon
1028 \fIWantedBy=multi\-user\&.target\fR
1035 \fBsystemctl enable\fR, a symlink
1036 /etc/systemd/system/multi\-user\&.target\&.wants/foo\&.service
1037 linking to the actual unit will be created\&. It tells systemd to pull in the unit when starting
1038 multi\-user\&.target\&. The inverse
1039 \fBsystemctl disable\fR
1040 will remove that symlink again\&.
1042 \fBExample\ \&2.\ \&Overriding vendor settings\fR
1044 There are two methods of overriding vendor settings in unit files: copying the unit file from
1045 /usr/lib/systemd/system
1048 and modifying the chosen settings\&. Alternatively, one can create a directory named
1052 and place a drop\-in file
1054 there that only changes the specific settings one is interested in\&. Note that multiple such drop\-in files are read if present\&.
1056 The advantage of the first method is that one easily overrides the complete unit, the vendor unit is not parsed at all anymore\&. It has the disadvantage that improvements to the unit file by the vendor are not automatically incorporated on updates\&.
1058 The advantage of the second method is that one only overrides the settings one specifically wants, where updates to the unit by the vendor automatically apply\&. This has the disadvantage that some future updates by the vendor might be incompatible with the local changes\&.
1060 Note that for drop\-in files, if one wants to remove entries from a setting that is parsed as a list (and is not a dependency), such as
1061 \fIConditionPathExists=\fR
1064 in service units), one needs to first clear the list before re\-adding all entries except the one that is to be removed\&. See below for an example\&.
1066 This also applies for user instances of systemd, but with different locations for the unit files\&. See the section on unit load paths for further details\&.
1068 Suppose there is a vendor\-supplied unit
1069 /usr/lib/systemd/system/httpd\&.service
1070 with the following contents:
1077 Description=Some HTTP server
1078 After=remote\-fs\&.target sqldb\&.service
1079 Requires=sqldb\&.service
1080 AssertPathExists=/srv/webserver
1084 ExecStart=/usr/sbin/some\-fancy\-httpd\-server
1088 WantedBy=multi\-user\&.target
1094 Now one wants to change some settings as an administrator: firstly, in the local setup,
1096 might not exist, because the HTTP server is configured to use
1098 instead\&. Secondly, the local configuration makes the HTTP server also depend on a memory cache service,
1099 memcached\&.service, that should be pulled in (\fIRequires=\fR) and also be ordered appropriately (\fIAfter=\fR)\&. Thirdly, in order to harden the service a bit more, the administrator would like to set the
1102 \fBsystemd.service\fR(5)
1103 for details)\&. And lastly, the administrator would like to reset the niceness of the service to its default value of 0\&.
1105 The first possibility is to copy the unit file to
1106 /etc/systemd/system/httpd\&.service
1107 and change the chosen settings:
1114 Description=Some HTTP server
1115 After=remote\-fs\&.target sqldb\&.service \fImemcached\&.service\fR
1116 Requires=sqldb\&.service \fImemcached\&.service\fR
1117 AssertPathExists=\fI/srv/www\fR
1121 ExecStart=/usr/sbin/some\-fancy\-httpd\-server
1123 \fIPrivateTmp=yes\fR
1126 WantedBy=multi\-user\&.target
1132 Alternatively, the administrator could create a drop\-in file
1133 /etc/systemd/system/httpd\&.service\&.d/local\&.conf
1134 with the following contents:
1141 After=memcached\&.service
1142 Requires=memcached\&.service
1143 # Reset all assertions and then re\-add the condition we want
1145 AssertPathExists=/srv/www
1155 Note that dependencies (\fIAfter=\fR, etc\&.) cannot be reset to an empty list, so dependencies can only be added in drop\-ins\&. If you want to remove dependencies, you have to override the entire unit\&.
1160 \fBsystemd.special\fR(7),
1161 \fBsystemd.service\fR(5),
1162 \fBsystemd.socket\fR(5),
1163 \fBsystemd.device\fR(5),
1164 \fBsystemd.mount\fR(5),
1165 \fBsystemd.automount\fR(5),
1166 \fBsystemd.swap\fR(5),
1167 \fBsystemd.target\fR(5),
1168 \fBsystemd.path\fR(5),
1169 \fBsystemd.timer\fR(5),
1170 \fBsystemd.snapshot\fR(5),
1171 \fBsystemd.scope\fR(5),
1172 \fBsystemd.slice\fR(5),
1173 \fBsystemd.time\fR(7),
1174 \fBsystemd-analyze\fR(1),
1175 \fBcapabilities\fR(7),
1176 \fBsystemd.directives\fR(7),
1180 XDG Desktop Entry Specification
1182 \%http://standards.freedesktop.org/desktop-entry-spec/latest/
1185 Interface Stability Promise
1187 \%http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise