X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd.unit.xml;h=953a2897ad488074839bf6f2f90f6bac449ea27e;hp=3236bfa7416f07670294827c0984ba6df5df9f6f;hb=74051b9b5865586bf4d30b9075649af838fb92bd;hpb=b2896c905bef7be7ed9a760d9d61aa6ad0f614a3
diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 3236bfa74..953a2897a 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -44,7 +44,7 @@
systemd.unit
- systemd unit configuration files
+ Unit configuration
@@ -75,13 +75,13 @@
inspired by Microsoft Windows
.ini files.
- This man pages lists the common configuration
+ This man page lists the common configuration
options of all the unit types. These options need to
- be configured in the [Unit] resp. [Install]
- section of the unit files.
+ be configured in the [Unit] or [Install]
+ sections of the unit files.In addition to the generic [Unit] and [Install]
- sections described here, each unit should have a
+ 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.
@@ -106,12 +106,14 @@
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
+ 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.
+ are understood: s, min, h, d, w, ms, us. For details
+ see
+ systemd.time7.
Empty lines and lines starting with # or ; are
ignored. This may be used for commenting. Lines ending
@@ -119,32 +121,42 @@
line while reading and the backslash is replaced by a
space character. This may be used to wrap long lines.
- If a line starts with
- followed by a file name, the specified file will be
- parsed at this point. Make sure that the file that is
- included has the appropriate section headers before
- any directives.
-
Along with a unit file
- foo.service a directory
+ foo.service the directory
foo.service.wants/ may exist. All
- units symlinked from such a directory are implicitly
- added as dependencies of type
+ unit files symlinked from such a directory are
+ implicitly added as dependencies of type
Wanted= to the unit. This is useful
to hook units into the start-up of other units,
- without having to modify their unit configuration
- files. For details about the semantics of
- Wanted= see below. The preferred
- way to create symlinks in the
- .wants/ directory of a service is
- with the enable command of the
+ without having to modify their unit files. For details
+ about the semantics of Wanted= see
+ below. The preferred way to create symlinks in the
+ .wants/ directory of a unit file
+ is with the enable command of the
systemctl1
tool which reads information from the [Install]
- section of unit files. (See below.) A similar
+ section of unit files (see below). A similar
functionality exists for Requires=
type dependencies as well, the directory suffix is
.requires/ in this case.
+ Along with a unit file
+ foo.service a directory
+ foo.service.d/ may exist. All
+ files with the suffix .conf 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.
+
+ If a line starts with
+ followed by a file name, the specified file will be
+ parsed at this point. Make sure that the file that is
+ included has the appropriate section headers before
+ any directives.
+
Note that while systemd offers a flexible
dependency system between units it is recommended to
use this functionality only sparsely and instead rely
@@ -186,91 +198,7 @@
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:
-
-
- Specifiers available in unit files
-
-
-
-
-
-
- Specifier
- Meaning
- Details
-
-
-
-
- %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.
-
-
- %P
- Unescaped prefix name
-
-
-
- %i
- Instance name
- This is the string between the @ character and the suffix.
-
-
- %I
- Unescaped instance name
-
-
-
- %f
- Unescaped file name
- This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /.
-
-
- %c
- Control group path of the unit
-
-
-
- %r
- Root control group path of systemd
-
-
-
- %R
- Parent directory of the root control group path of systemd
-
-
-
- %t
- Runtime socket dir
- This is either /run (for the system manager) or $XDG_RUNTIME_DIR (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.
-
-
- %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.
-
-
-
-
+ 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
@@ -284,6 +212,7 @@
Interface
Stability Promise.
+
@@ -318,7 +247,20 @@
man:. For more
information about the syntax of these
URIs see
- uri7.
+ 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.
@@ -358,7 +300,15 @@
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.
@@ -390,7 +340,7 @@
Similar to
Requires=
- resp. RequiresOverridable=. However,
+ and RequiresOverridable=, respectively. However,
if a unit listed here is not started
already it will not be started and the
transaction fails
@@ -410,7 +360,9 @@
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
@@ -425,7 +377,7 @@
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,
@@ -436,6 +388,21 @@
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=
@@ -521,7 +488,7 @@
Before=. If two
units have no ordering dependencies
between them they are shut down
- resp. started up simultaneously, and
+ or started up simultaneously, and
no ordering takes
place.
@@ -556,7 +523,7 @@
RequiresMountsFor=Takes a space
- separated list of paths. Automatically
+ separated list of absolute paths. Automatically
adds dependencies of type
Requires= and
After= for all
@@ -627,13 +594,13 @@
Takes a boolean
argument. If
this unit can only be activated
- (resp. deactivated) indirectly. In
+ or deactivated indirectly. In
this case explicit start-up
- (resp. termination) requested by the
+ 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
@@ -725,70 +692,100 @@
ConditionPathIsMountPoint=ConditionPathIsReadWrite=ConditionDirectoryNotEmpty=
+ ConditionFileNotEmpty=ConditionFileIsExecutable=ConditionKernelCommandLine=ConditionVirtualization=ConditionSecurity=ConditionCapability=
+ ConditionHost=
+ ConditionACPower=ConditionNull=Before starting a unit
verify that the specified condition is
- true. With
+ 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.
+
+ With
ConditionPathExists=
- a file existence condition can be
+ a file existence condition is
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
+ 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
+ ('!'), 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=
+ 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=
+ directory.
+
+ ConditionPathIsSymbolicLink=
is similar to
ConditionPathExists=
but verifies whether a certain path
exists and is a symbolic
- link. ConditionPathIsMountPoint=
+ link.
+
+ ConditionPathIsMountPoint=
is similar to
ConditionPathExists=
but verifies whether a certain path
exists and is a mount
- point. ConditionPathIsReadWrite=
+ point.
+
+ ConditionPathIsReadWrite=
is similar to
ConditionPathExists=
but verifies whether the underlying
- file system is read and writable
+ file system is readable and writable
(i.e. not mounted
- read-only). ConditionFileIsExecutable=
+ read-only).
+
+ ConditionDirectoryNotEmpty=
is similar to
ConditionPathExists=
but verifies whether a certain path
- exists, is a regular file and marked
- executable.
- ConditionDirectoryNotEmpty=
+ exists and is a non-empty
+ directory.
+
+ ConditionFileNotEmpty=
is similar to
ConditionPathExists=
but verifies whether a certain path
- exists and is a non-empty
- directory. Similarly
+ 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.
+
+ Similar,
ConditionKernelCommandLine=
may be used to check whether a
specific kernel command line option is
@@ -796,14 +793,16 @@
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
+ '='). 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=
+ matching.
+
+ ConditionVirtualization=
may be used to check whether the
system is executed in a virtualized
environment and optionally test
@@ -813,7 +812,7 @@
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,
@@ -832,15 +831,18 @@
virtualization technologies are nested
only the innermost is considered. The
test may be negated by prepending an
- exclamation mark.
- ConditionSecurity=
+ exclamation mark.
+
+ 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=
+ mark.
+
+ ConditionCapability=
may be used to check whether the given
capability exists in the capability
bounding set of the service manager
@@ -851,14 +853,49 @@
for details). Pass a capability name
such as CAP_MKNOD,
possibly prefixed with an exclamation
- mark to negate the check. Finally,
+ mark to negate the check.
+
+ ConditionHost=
+ may be used to match against the
+ host name or machine ID of the
+ host. This either takes a host name
+ string (optionally with shell style
+ globs) which is tested against the
+ locally set host name as returned by
+ gethostname2,
+ or a machine ID formatted as string
+ (see
+ machine-id5).
+ The test may be negated by prepending
+ an exclamation mark.
+
+ 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
+ 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.
+
+ Finally,
ConditionNull= may
be used to add a constant condition
check value to the unit. It takes a
boolean argument. If set to
false the condition
will always fail, otherwise
- succeed. If multiple conditions are
+ succeed.
+
+ 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
@@ -875,8 +912,12 @@
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.
@@ -926,8 +967,8 @@
Installs a symlink in
the .wants/
- resp. .requires/
- subdirectory for a unit. This has the
+ or .requires/
+ subdirectory for a unit, respectively. This has the
effect that when the listed unit name
is activated the unit listing it is
activated
@@ -956,6 +997,124 @@
+
+ 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
+
+
+
+ %p
+ Prefix name
+ For instantiated units this refers to the string before the @. For non-instantiated units this refers to to the name of the unit with the type suffix removed.
+
+
+ %P
+ Unescaped prefix name
+
+
+
+ %i
+ Instance name
+ For instantiated units: this is the string between the @ character and the suffix.
+
+
+ %I
+ Unescaped instance name
+
+
+
+ %f
+ Unescaped file name
+ This is either the unescaped instance name (if applicable) with / prepended (if applicable), or the prefix name similarly prepended with /.
+
+
+ %c
+ Control group path of the unit
+
+
+
+ %r
+ Root control group path of systemd
+
+
+
+ %R
+ Parent directory of the root control group path of systemd
+
+
+
+ %t
+ Runtime socket dir
+ This is either /run (for the system manager) or $XDG_RUNTIME_DIR (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 UID of the configured user of the unit, or (if none is set) the user running the systemd instance.
+
+
+ %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.
+
+
+ %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.
+
+
+ %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 host name of the running system.
+
+
+
+
+
+
See Also
@@ -972,7 +1131,9 @@
systemd.path5,
systemd.timer5,
systemd.snapshot5,
- capabilities7
+ systemd.time7,
+ capabilities7,
+ systemd.directives7