X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd.unit.xml;h=bf0deb1f97cd64d983a67daf1f9e0f25b58e4281;hp=286862006a9ab503027085e679a97f9eed3f668a;hb=e45fc5e738b0b7700e8b4f3c4b25c58a49b44b27;hpb=34511ca7b166b0e89d08ff9870b0cf2624a7815f diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml index 286862006..bf0deb1f9 100644 --- a/man/systemd.unit.xml +++ b/man/systemd.unit.xml @@ -1,6 +1,9 @@ + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ + +%entities; +]> + Note that while systemd offers a flexible dependency system between units it is recommended to - use this functionality only sparsely and instead rely + use this functionality only sparingly and instead rely on techniques such as bus-based or socket-based - activation which makes dependencies implicit, which - both results in a simpler and more flexible - system. + activation which make dependencies implicit, resulting + in a both simpler and more flexible system. Some unit names reflect paths existing in the - file system name space. Example: a device unit + file system namespace. Example: a device unit dev-sda.device refers to a device - with the device node /dev/sda in - the file system namespace. If this applies a special + with the device node /dev/sda 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 file name. Basically, - given a path, "/" is replaced by "-", and all - unprintable characters and the "-" are replaced by - C-style "\x20" escapes. The root directory "/" is - encoded as single dash, while otherwise the initial - and ending "/" is removed from all paths during - transformation. This escaping is reversible. + 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 "\x2d" 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 systemd-escape1 + command. 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 + systemd looks for a unit configuration file, it will first search for the literal unit name in the - filesystem. If that yields no success and the unit - name contains an @ character, systemd will look for a + file system. If that yields no success and the unit + name contains an @ character, systemd will look for a unit template that shares the same name but with the - instance string (i.e. the part between the @ character + instance string (i.e. the part between the @ character and the suffix) removed. Example: if a service getty@tty3.service is requested and no file by that name is found, systemd will look @@ -186,119 +260,141 @@ To refer to the instance string from within the configuration file you may use the special %i specifier in many of the - configuration options. Other specifiers exist, the - full list is: + configuration options. See below for details. + + If a unit file is empty (i.e. has the file size + 0) or is symlinked to /dev/null, + its configuration will not be loaded and it appears + with a load state of masked, and + cannot be activated. Use this as an effective way to + fully disable a unit, making it impossible to start it + even manually. + + The unit file format is covered by the + Interface + Stability Promise. + + + + + Unit Load Path + + 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. + + When systemd is running in user mode + () and the variable + $SYSTEMD_UNIT_PATH is set, this + contents of this variable overrides the unit load + path. If $SYSTEMD_UNIT_PATH ends + with an empty component (:), the + usual unit load path will be appended to the contents + of the variable. - Specifiers available in unit files - - - - + + Load path when running in system mode (<option>--system</option>). + + + + + - Specifier - Meaning - Details + Path + Description - %n - Full unit name - - - - %N - Unescaped full unit name - - - - %p - Prefix name - This refers to the string before the @, i.e. "getty" in the example above, where "tty3" is the instance name. + /etc/systemd/system + Local configuration - %P - Unescaped prefix name - + /run/systemd/system + Runtime units - %i - Instance name - This is the string between the @ character and the suffix. + /usr/lib/systemd/system + Units of installed packages + + +
+ + + + Load path when running in user mode (<option>--user</option>). + + + + + + - %I - Unescaped instance name - + Path + Description + + - %f - Unescaped file name - This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /. + $XDG_CONFIG_HOME/systemd/user + User configuration (only used when $XDG_CONFIG_HOME is set) - %c - Control group path of the unit - + $HOME/.config/systemd/user + User configuration (only used when $XDG_CONFIG_HOME is not set) - %r - Root control group path of systemd - + /etc/systemd/user + Local configuration - %R - Parent directory of the root control group path of systemd - + $XDG_RUNTIME_DIR/systemd/user + Runtime units (only used when $XDG_RUNTIME_DIR is set) - %t - Runtime socket dir - This is either /run (for the system manager) or $XDG_RUNTIME_DIR (for user managers). + /run/systemd/user + Runtime units - %u - User name - This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance. + $XDG_DATA_HOME/systemd/user + Units of packages that have been installed in the home directory (only used when $XDG_DATA_HOME is set) - %h - User home directory - This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance. + $HOME/.local/share/systemd/user + Units of packages that have been installed in the home directory (only used when $XDG_DATA_HOME is not set) - %s - User shell - This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance. + /usr/lib/systemd/user + Units of packages that have been installed system-wide
- If a unit file is empty (i.e. has the file size - 0) or is symlinked to /dev/null - its configuration will not be loaded and it appears - with a load state of masked, and - cannot be activated. Use this as an effective way to - fully disable a unit, making it impossible to start it - even manually. - - The unit file format is covered by the + Additional units might be loaded into systemd + ("linked") from directories not on the unit load + path. See the link command for + systemctl1. Also, + some units are dynamically created via generators Interface - Stability Promise. + url="http://www.freedesktop.org/wiki/Software/systemd/Generators/">Generators. + - Options + [Unit] Section Options Unit file may include a [Unit] section, which carries generic information about the unit that is not dependent on the type of unit: - + Description= @@ -306,12 +402,20 @@ describing the unit. This is intended for use in UIs to show descriptive information along with the unit - name. + name. The description should contain a name + that means something to the end user. + Apache2 Web Server is a good + example. Bad examples are + high-performance light-weight HTTP + server (too generic) or + Apache2 (too specific and + meaningless for people who do not know + Apache). Documentation= - A space separated list + A space-separated list of URIs referencing documentation for this unit or its configuration. Accepted are only URIs @@ -322,8 +426,21 @@ info:, man:. For more information about the syntax of these - URIs see - uri7. + URIs, see + uri7. 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's 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. @@ -336,10 +453,12 @@ of the other units gets deactivated or its activation fails, this unit will be deactivated. This option may be - specified more than once, in which - case requirement dependencies for all - listed names are created. Note that - requirement dependencies do not + 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 @@ -363,7 +482,15 @@ Requires= in order to achieve a system that is more robust when dealing with failing - services. + services. + + Note that dependencies of this + type may also be configured outside of + the unit configuration file by + adding a symlink to a + .requires/ directory + accompanying the unit file. For + details see above. @@ -379,7 +506,7 @@ 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 + requested by the user, this dependency must be fulfilled and otherwise the transaction fails. Hence, this option may be used to configure dependencies @@ -394,34 +521,37 @@ RequisiteOverridable= Similar to - Requires= - resp. RequiresOverridable=. However, - if a unit listed here is not started - already it will not be started and the - transaction fails - immediately. + Requires= and + RequiresOverridable=, + respectively. However, if the units + listed here are not started already, + they will not be started and the + transaction will fail immediately. + Wants= A weaker version of - Requires=. A unit + Requires=. Units listed in this option will be started if the configuring unit is. However, - if the listed unit fails to start up - or cannot be added to the transaction + 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. Note that dependencies of this + unit. + + Note that dependencies of this type may also be configured outside of - the unit configuration file by - adding a symlink to a + the unit configuration file by adding + symlinks to a .wants/ directory accompanying the unit file. For - details see above. + details, see above. @@ -430,7 +560,7 @@ Configures requirement dependencies, very similar in style to Requires=, however - in addition to this behaviour it also + in addition to this behavior, it also declares that this unit is stopped when any of the units listed suddenly disappears. Units can suddenly, @@ -441,15 +571,30 @@ systemd. + + PartOf= + + Configures dependencies + similar to Requires=, + 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 — + changes to this unit do not affect the + listed units. + + + Conflicts= - Configures negative + A space-separated list + of unit names. Configures negative requirement dependencies. If a unit - has a - Conflicts= setting - on another unit, starting the former - will stop the latter and vice + has a Conflicts= + 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 After= and @@ -464,9 +609,9 @@ 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 + case, the job that is not the required will be removed, or in case both are - not required the unit that conflicts + not required, the unit that conflicts will be started and the unit that is conflicted is stopped. @@ -476,7 +621,8 @@ Before= After= - Configures ordering + A space-separated list + of unit names. Configures ordering dependencies between units. If a unit foo.service contains a setting @@ -492,7 +638,7 @@ a common pattern to include a unit name in both the After= and - Requires= option in + Requires= option, in which case the unit listed will be started before the unit that is configured with these options. This @@ -520,24 +666,24 @@ dependency on another unit is shut down while the latter is started up, the shut down is ordered before the - start-up regardless whether the + start-up regardless of whether the ordering dependency is actually of type After= or Before=. If two units have no ordering dependencies - between them they are shut down - resp. started up simultaneously, and - no ordering takes + between them, they are shut down or + started up simultaneously, and no + ordering takes place. OnFailure= - Lists one or more - units that are activated when this - unit enters the - 'failed' + A space-separated list + of one or more units that are + activated when this unit enters the + failed state. @@ -545,51 +691,106 @@ PropagatesReloadTo= ReloadPropagatedFrom= - Lists one or more - units where reload requests on the - unit will be propagated to/on the - other unit will be propagated - from. 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. + 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. + + + + JoinsNamespaceOf= + + 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 + PrivateNetwork= and + PrivateTmp= + directives (see + systemd.exec5 + for details). If a unit that has this + setting set is started, its processes + will see the same + /tmp, + /tmp/var 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 + PrivateNetwork= + and/or PrivateTmp= + is enabled for both the unit that + joins the namespace and the unit whose + namespace is joined. RequiresMountsFor= - Takes a space - separated list of paths. Automatically - adds dependencies of type - Requires= and - After= for all + Takes a + space-separated list of absolute + paths. Automatically adds dependencies + of type Requires= + and After= for all mount units required to access the - specified path. + specified path. + + Mount points marked with + 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 + (Requires= and + After= or + some other combination). + - OnFailureIsolate= - - Takes a boolean - argument. If the - unit listed in + OnFailureJobMode= + + Takes a value of + fail, + replace, + replace-irreversibly, + isolate, + flush, + ignore-dependencies + or + ignore-requirements. Defaults + to + replace. Specifies + how the units listed in OnFailure= will be - enqueued in isolation mode, i.e. all - units that are not its dependency will - be stopped. If this is set only a + enqueued. See + systemctl1's + option + for details on the possible values. If + this is set to + isolate, only a single unit may be listed in - OnFailure=. Defaults - to - . + OnFailure=.. IgnoreOnIsolate= Takes a boolean - argument. If + argument. If , this unit will not be stopped when isolating another unit. Defaults to . @@ -599,7 +800,7 @@ IgnoreOnSnapshot= Takes a boolean - argument. If + argument. If , this unit will not be included in snapshots. Defaults to for device and @@ -611,7 +812,7 @@ StopWhenUnneeded= Takes a boolean - argument. If + argument. If , this unit will be stopped when it is no longer used. Note that in order to minimize the work to be executed, @@ -630,15 +831,15 @@ RefuseManualStop= Takes a boolean - argument. If + argument. If , this unit can only be activated - (resp. deactivated) indirectly. In - this case explicit start-up - (resp. termination) requested by the + or deactivated indirectly. In + this case, explicit start-up + or termination requested by the user is denied, however if it is - started (resp. stopped) as a + started or stopped as a dependency of another unit, start-up - (resp. termination) will succeed. This + or termination will succeed. This is mostly a safety feature to ensure that the user does not accidentally activate units that are not intended @@ -653,10 +854,10 @@ AllowIsolate= Takes a boolean - argument. If + argument. If , this unit may be used with the systemctl isolate - command. Otherwise this will be + 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 @@ -670,7 +871,7 @@ DefaultDependencies= Takes a boolean - argument. If + argument. If , (the default), a few default dependencies will implicitly be created for the unit. The actual @@ -688,7 +889,7 @@ highly recommended to leave this option enabled for the majority of common units. If set to - this option + , this option does not disable all implicit dependencies, just non-essential ones. @@ -696,20 +897,22 @@ JobTimeoutSec= - - When clients are - waiting for a job of this unit to - complete, time out after the specified - time. If this time limit is reached - the job will be cancelled, the unit - however will not change state or even - enter the 'failed' - mode. This value defaults to 0 (job - timeouts disabled), except for device + JobTimeoutAction= + JobTimeoutRebootArgument= + + 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 + failed 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 - Timeout= in service + StartTimeoutSec= 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 @@ -719,10 +922,34 @@ timeout set with this option however is useful to abort only the job waiting for the unit state to - change. + change. + + JobTimeoutAction= + optionally configures an additional + action to take when the time-out is + hit. It takes the same values as the + per-service + StartLimitAction= + setting, see + systemd.service5 + for details. Defaults to + . JobTimeoutRebootArgument= + configures an optional reboot string + to pass to the + reboot2 + system call. + ConditionArchitecture= + ConditionVirtualization= + ConditionHost= + ConditionKernelCommandLine= + ConditionSecurity= + ConditionCapability= + ConditionACPower= + ConditionNeedsUpdate= + ConditionFirstBoot= ConditionPathExists= ConditionPathExistsGlob= ConditionPathIsDirectory= @@ -730,85 +957,74 @@ ConditionPathIsMountPoint= ConditionPathIsReadWrite= ConditionDirectoryNotEmpty= + ConditionFileNotEmpty= ConditionFileIsExecutable= - ConditionKernelCommandLine= - ConditionVirtualization= - ConditionSecurity= - ConditionCapability= - ConditionNull= + + Before starting a unit verify that the specified condition is - true. With - ConditionPathExists= - a file existence condition can be - checked before a unit is started. If - the specified absolute path name does - not exist, startup of a unit will not - actually happen, however the unit is - still useful for ordering purposes in - this case. The condition is checked at - the time the queued start job is to be - executed. If the absolute path name - passed to - ConditionPathExists= - is prefixed with an exclamation mark - (!), the test is negated, and the unit - is only started if the path does not - exist. - ConditionPathExistsGlob= - works in a similar way, but checks for - the existence of at least one file or - directory matching the specified - globbing - pattern. ConditionPathIsDirectory= - is similar to - ConditionPathExists= - but verifies whether a certain path - exists and is a - directory. ConditionPathIsSymbolicLink= - is similar to - ConditionPathExists= - but verifies whether a certain path - exists and is a symbolic - link. ConditionPathIsMountPoint= - is similar to - ConditionPathExists= - but verifies whether a certain path - exists and is a mount - point. ConditionPathIsReadWrite= - is similar to - ConditionPathExists= - but verifies whether the underlying - file system is read and writable - (i.e. not mounted - read-only). ConditionFileIsExecutable= - is similar to - ConditionPathExists= - but verifies whether a certain path - exists, is a regular file and marked - executable. - ConditionDirectoryNotEmpty= - is similar to - ConditionPathExists= - but verifies whether a certain path - exists and is a non-empty - directory. Similarly - ConditionKernelCommandLine= - 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 - by the equality sign). 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. ConditionVirtualization= + 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. + + ConditionArchitecture= + may be used to check whether the + system is running on a specific + architecture. Takes one of + x86, + x86-64, + ppc, + ppc-le, + ppc64, + ppc64-le, + ia64, + parisc, + parisc64, + s390, + s390x, + sparc, + sparc64, + mips, + mips-le, + mips64, + mips64-le, + alpha, + arm, + arm-be, + arm64, + arm64-be, + sh, + sh64, + m86k, + tilegx, + cris to test + against a specific architecture. The + architecture is determined from the + information returned by + uname2 + and is thus subject to + personality2. Note + that a Personality= + setting in the same unit file has no + effect on this condition. A special + architecture name + native is mapped to + the architecture the system manager + itself is compiled for. The test may + be negated by prepending an + exclamation mark. + + ConditionVirtualization= may be used to check whether the system is executed in a virtualized environment and optionally test @@ -818,70 +1034,270 @@ any virtualized environment, or one of vm and container to test - against a specific type of + against a generic type of virtualization solution, or one of qemu, kvm, + zvm, vmware, microsoft, oracle, xen, bochs, - chroot, + uml, openvz, lxc, lxc-libvirt, - systemd-nspawn to - test against a specific - implementation. If multiple - virtualization technologies are nested - only the innermost is considered. The - test may be negated by prepending an - exclamation mark. - ConditionSecurity= + systemd-nspawn, + docker to test + against a specific implementation. See + systemd-detect-virt1 + 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. + + ConditionHost= + 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 + gethostname2, + or a machine ID formatted as string + (see + machine-id5). + The test may be negated by prepending + an exclamation mark. + + ConditionKernelCommandLine= + 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 + =). 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. + + ConditionSecurity= may be used to check whether the given security module is enabled on the - system. Currently the only recognized - value is selinux. - The test may be negated by prepending - an exclamation - mark. ConditionCapability= + system. Currently the recognized + values values are + selinux, + apparmor, + ima, + smack and + audit. The test may + be negated by prepending an + exclamation mark. + + ConditionCapability= 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 - capabilities7 + capabilities7 for details). Pass a capability name such as CAP_MKNOD, possibly prefixed with an exclamation - mark to negate the check. Finally, - ConditionNull= may - be used to add a constant condition - check value to the unit. It takes a + mark to negate the check. + + ConditionACPower= + 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 - false the condition - will always fail, otherwise - succeed. If multiple conditions are - specified the unit will be executed if + true, 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 false, the + condition will hold only if there is + at least one AC connector known and + all AC connectors are disconnected + from a power source. + + ConditionNeedsUpdate= + takes one of /var + or /etc as + argument, possibly prefixed with a + ! (for inverting + the condition). This condition may be + used to conditionalize units on + whether the specified directory + requires an update because + /usr's + modification time is newer than the + stamp file + .updated in the + specified directory. This is useful to + implement offline updates of the + vendor operating system resources in + /usr that require + updating of /etc + or /var on the + next following boot. Units making use + of this condition should order + themselves before + systemd-update-done.service8, + to make sure they run before the stamp + files's modification time gets reset + indicating a completed update. + + ConditionFirstBoot= + takes a boolean argument. This + condition may be used to + conditionalize units on whether the + system is booting up with an + unpopulated /etc + directory. This may be used to + populate /etc on + the first boot after factory reset, or + when a new system instances boots up + for the first time. + + With + ConditionPathExists= + 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 + ConditionPathExists= + is prefixed with an exclamation mark + (!), the test is negated, and the unit + is only started if the path does not + exist. + + ConditionPathExistsGlob= + is similar to + ConditionPathExists=, + but checks for the existence of at + least one file or directory matching + the specified globbing pattern. + + ConditionPathIsDirectory= + is similar to + ConditionPathExists= + but verifies whether a certain path + exists and is a + directory. + + ConditionPathIsSymbolicLink= + is similar to + ConditionPathExists= + but verifies whether a certain path + exists and is a symbolic + link. + + ConditionPathIsMountPoint= + is similar to + ConditionPathExists= + but verifies whether a certain path + exists and is a mount + point. + + ConditionPathIsReadWrite= + is similar to + ConditionPathExists= + but verifies whether the underlying + file system is readable and writable + (i.e. not mounted + read-only). + + ConditionDirectoryNotEmpty= + is similar to + ConditionPathExists= + but verifies whether a certain path + exists and is a non-empty + directory. + + ConditionFileNotEmpty= + is similar to + ConditionPathExists= + but verifies whether a certain path + exists and refers to a regular file + with a non-zero size. + + ConditionFileIsExecutable= + is similar to + ConditionPathExists= + but verifies whether a certain path + exists, is a regular file and marked + executable. + + 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 + 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 + symbol and an exclamation mark, the pipe symbol must be passed first, the exclamation second. Except for ConditionPathIsSymbolicLink=, - all path checks follow - symlinks. + 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. + + + + AssertArchitecture= + AssertVirtualization= + AssertHost= + AssertKernelCommandLine= + AssertSecurity= + AssertCapability= + AssertACPower= + AssertNeedsUpdate= + AssertFirstBoot= + AssertPathExists= + AssertPathExistsGlob= + AssertPathIsDirectory= + AssertPathIsSymbolicLink= + AssertPathIsMountPoint= + AssertPathIsReadWrite= + AssertDirectoryNotEmpty= + AssertFileNotEmpty= + AssertFileIsExecutable= + + Similar to the + ConditionArchitecture=, + ConditionVirtualization=, + ... 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. @@ -892,15 +1308,21 @@ useful for implementation of generator tools that convert configuration from an external configuration file format - into native unit files. Thus + into native unit files. This functionality should not be used in normal units. - Unit file may include a [Install] section, which - carries installation information for the unit. This - section is not interpreted by + + + + [Install] Section Options + + Unit file may include an + [Install] section, which carries + installation information for the unit. This section is + not interpreted by systemd1 during runtime. It is used exclusively by the enable and @@ -908,64 +1330,254 @@ systemctl1 tool during installation of a unit: - + Alias= - 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, - systemctl enable - will create symlinks from these names - to the unit file name. + 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, systemctl + enable will create symlinks + from these names to the unit + filename. WantedBy= RequiredBy= - Installs a symlink in - the .wants/ - resp. .requires/ - subdirectory for a unit. This has the - effect that when the listed unit name - is activated the unit listing it is - activated - too. WantedBy=foo.service + 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 .wants/ or + .requires/ + directory of each of the listed units + when this unit is installed by + systemctl enable. + This has the effect that a dependency + of type Wants= or + Requires= 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 + Wants= and + Requires= in the + [Unit] section for details. + + WantedBy=foo.service in a service bar.service is mostly equivalent to Alias=foo.service.wants/bar.service - in the same file. + in the same file. In case of template + units, systemctl enable + must be called with an instance name, and + this instance will be added to the + .wants/ or + .requires/ list + of the listed unit. + E.g. WantedBy=getty.target + in a service + getty@.service + will result in systemctl + enable getty@tty2.service + creating a + getty.target.wants/getty@tty2.service + link to getty@.service. + Also= Additional units to - install when this unit is - installed. If the user requests - installation of a unit with this - option configured, + install/deinstall when this unit is + installed/deinstalled. If the user + requests installation/deinstallation + of a unit with this option configured, systemctl enable - will automatically install units - listed in this option as - well. + and systemctl + disable will automatically + install/uninstall units listed in this option as + well. + + This option may be used more + than once, or a space-separated list + of unit names may be + given. + + + + DefaultInstance= + + 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. + 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. + + + + + Specifiers + + 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: + + + Specifiers available in unit files + + + + + + + Specifier + Meaning + Details + + + + + %n + Full unit name + + + + %N + Unescaped full unit name + Same as %n, but with escaping undone + + + %p + Prefix name + 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. + + + %P + Unescaped prefix name + Same as %p, but with escaping undone + + + %i + Instance name + For instantiated units: this is the string between the @ character and the suffix of the unit name. + + + %I + Unescaped instance name + Same as %i, but with escaping undone + + + %f + Unescaped filename + This is either the unescaped instance name (if applicable) with / prepended (if applicable), or the prefix name prepended with /. + + + %c + Control group path of the unit + This path does not include the /sys/fs/cgroup/systemd/ prefix. + + + %r + Control group path of the slice the unit is placed in + This usually maps to the parent cgroup path of %c. + + + %R + Root control group path below which slices and units are placed + For system instances, this resolves to /, except in containers, where this maps to the container's root control group path. + + + %t + Runtime directory + This is either /run (for the system manager) or the path $XDG_RUNTIME_DIR resolves to (for user managers). + + + %u + User name + This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance. + + + %U + User UID + 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. + + + %h + User home directory + 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. + + + %s + User shell + 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. + + + %m + Machine ID + The machine ID of the running system, formatted as string. See machine-id5 for more information. + + + %b + Boot ID + The boot ID of the running system, formatted as string. See random4 for more information. + + + %H + Host name + The hostname of the running system at the point in time the unit configuation is loaded. + + + %v + Kernel release + Identical to uname -r output + + + %% + Single percent sign + Use %% in place of % to specify a single percent sign. + + + +
+ + Please note that specifiers + %U, %h, + %s 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 mode. See Also systemd1, - systemctl8, + systemctl1, systemd.special7, systemd.service5, systemd.socket5, @@ -977,7 +1589,13 @@ systemd.path5, systemd.timer5, systemd.snapshot5, - capabilities7 + systemd.scope5, + systemd.slice5, + systemd.time7, + systemd-analyze1, + capabilities7, + systemd.directives7, + uname1