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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
+<!ENTITY % entities SYSTEM "custom-entities.ent" >
+%entities;
+]>
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This file is part of systemd.
</refnamediv>
<refsynopsisdiv>
- <para><filename>systemd.service</filename>,
- <filename>systemd.socket</filename>,
- <filename>systemd.device</filename>,
- <filename>systemd.mount</filename>,
- <filename>systemd.automount</filename>,
- <filename>systemd.swap</filename>,
- <filename>systemd.target</filename>,
- <filename>systemd.path</filename>,
- <filename>systemd.timer</filename>,
- <filename>systemd.snapshot</filename></para>
+ <para><filename><replaceable>service</replaceable>.service</filename>,
+ <filename><replaceable>socket</replaceable>.socket</filename>,
+ <filename><replaceable>device</replaceable>.device</filename>,
+ <filename><replaceable>mount</replaceable>.mount</filename>,
+ <filename><replaceable>automount</replaceable>.automount</filename>,
+ <filename><replaceable>swap</replaceable>.swap</filename>,
+ <filename><replaceable>target</replaceable>.target</filename>,
+ <filename><replaceable>path</replaceable>.path</filename>,
+ <filename><replaceable>timer</replaceable>.timer</filename>,
+ <filename><replaceable>snapshot</replaceable>.snapshot</filename>,
+ <filename><replaceable>slice</replaceable>.slice</filename>,
+ <filename><replaceable>scope</replaceable>.scope</filename></para>
+
+ <para><literallayout><filename>/etc/systemd/system/*</filename>
+<filename>/run/systemd/system/*</filename>
+<filename>/usr/lib/systemd/system/*</filename>
+<filename>...</filename>
+ </literallayout></para>
+
+ <para><literallayout><filename>$HOME/.config/systemd/user/*</filename>
+<filename>/etc/systemd/user/*</filename>
+<filename>/run/systemd/user/*</filename>
+<filename>/usr/lib/systemd/user/*</filename>
+<filename>...</filename>
+ </literallayout></para>
</refsynopsisdiv>
<refsect1>
<para>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 file system path or a timer controlled and
- supervised by
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>. The
- syntax is inspired by <ulink
+ target, a watched file system path, a timer controlled
+ and supervised by
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ a temporary system state snapshot, a resource
+ management slice or a group of externally created
+ processes. The syntax is inspired by <ulink
url="http://standards.freedesktop.org/desktop-entry-spec/latest/">XDG
- Desktop Entry Specification</ulink> <filename>.desktop</filename> files, which are in turn
+ Desktop Entry Specification</ulink>
+ <filename>.desktop</filename> files, which are in turn
inspired by Microsoft Windows
<filename>.ini</filename> files.</para>
sections of the unit files.</para>
<para>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.</para>
+ information:
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ </para>
+
+ <para>Unit files are loaded from a set of paths
+ determined during compilation, described in the next section.
+ </para>
<para>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
+ option, it will write a warning log message but
continue loading the unit. If an option is prefixed
- with <option>X-</option> it is ignored completely by
+ with <option>X-</option>, it is ignored completely by
systemd. Applications may use this to include
additional information in the unit files.</para>
written in various formats. For positive settings the
strings <option>1</option>, <option>yes</option>,
<option>true</option> and <option>on</option> are
- equivalent. For negative settings the strings
+ equivalent. For negative settings, the strings
<option>0</option>, <option>no</option>,
<option>false</option> and <option>off</option> are
equivalent.</para>
<para>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. For details see <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+ are understood: s, min, h, d, w, ms, us. For details
+ see
+ <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
<para>Empty lines and lines starting with # or ; are
ignored. This may be used for commenting. Lines ending
line while reading and the backslash is replaced by a
space character. This may be used to wrap long lines.</para>
- <para>If a line starts with <option>.include</option>
- 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.</para>
-
<para>Along with a unit file
- <filename>foo.service</filename> a directory
+ <filename>foo.service</filename>, the directory
<filename>foo.service.wants/</filename> 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
<varname>Wanted=</varname> 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
- <varname>Wanted=</varname> see below. The preferred
- way to create symlinks in the
- <filename>.wants/</filename> directory of a service is
- with the <command>enable</command> command of the
+ without having to modify their unit files. For details
+ about the semantics of <varname>Wanted=</varname>, see
+ below. The preferred way to create symlinks in the
+ <filename>.wants/</filename> directory of a unit file
+ is with the <command>enable</command> command of the
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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 <varname>Requires=</varname>
type dependencies as well, the directory suffix is
<filename>.requires/</filename> in this case.</para>
+ <para>Along with a unit file
+ <filename>foo.service</filename>, a directory
+ <filename>foo.service.d/</filename> may exist. All
+ files with the suffix <literal>.conf</literal> 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.</para>
+
+ <para>If a line starts with <option>.include</option>
+ followed by a filename, 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.</para>
+
<para>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.</para>
+ activation which make dependencies implicit, resulting
+ in a both simpler and more flexible system.</para>
<para>Some unit names reflect paths existing in the
- file system name space. Example: a device unit
+ file system namespace. Example: a device unit
<filename>dev-sda.device</filename> refers to a device
- with the device node <filename>/dev/sda</filename> in
- the file system namespace. If this applies a special
+ with the device node <filename noindex='true'>/dev/sda</filename> 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,
+ result is usable as part of a filename. Basically,
given a path, "/" is replaced by "-", and all
unprintable characters and the "-" are replaced by
C-style "\x20" escapes. The root directory "/" is
<para>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
+ name contains an <literal>@</literal> 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 <literal>@</literal> character
and the suffix) removed. Example: if a service
<filename>getty@tty3.service</filename> is requested
and no file by that name is found, systemd will look
<para>To refer to the instance string from
within the configuration file you may use the special
<literal>%i</literal> specifier in many of the
- configuration options. Other specifiers exist, the
- full list is:</para>
+ configuration options. See below for details.</para>
+
+ <para>If a unit file is empty (i.e. has the file size
+ 0) or is symlinked to <filename>/dev/null</filename>,
+ its configuration will not be loaded and it appears
+ with a load state of <literal>masked</literal>, and
+ cannot be activated. Use this as an effective way to
+ fully disable a unit, making it impossible to start it
+ even manually.</para>
+
+ <para>The unit file format is covered by the
+ <ulink
+ url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
+ Stability Promise</ulink>.</para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Unit Load Path</title>
+
+ <para>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.</para>
+
+ <para>When systemd is running in user mode
+ (<option>--user</option>) and the variable
+ <varname>$SYSTEMD_UNIT_PATH</varname> is set, this
+ contents of this variable overrides the unit load
+ path.
+ </para>
<table>
- <title>Specifiers available in unit files</title>
- <tgroup cols='3' align='left' colsep='1' rowsep='1'>
- <colspec colname="spec" />
- <colspec colname="mean" />
- <colspec colname="detail" />
+ <title>
+ Load path when running in system mode (<option>--system</option>).
+ </title>
+
+ <tgroup cols='2'>
+ <colspec colname='path' />
+ <colspec colname='expl' />
<thead>
<row>
- <entry>Specifier</entry>
- <entry>Meaning</entry>
- <entry>Details</entry>
+ <entry>Path</entry>
+ <entry>Description</entry>
</row>
</thead>
<tbody>
<row>
- <entry><literal>%n</literal></entry>
- <entry>Full unit name</entry>
- <entry></entry>
+ <entry><filename>/etc/systemd/system</filename></entry>
+ <entry>Local configuration</entry>
</row>
<row>
- <entry><literal>%N</literal></entry>
- <entry>Unescaped full unit name</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%p</literal></entry>
- <entry>Prefix name</entry>
- <entry>This refers to the string before the @, i.e. "getty" in the example above, where "tty3" is the instance name.</entry>
- </row>
- <row>
- <entry><literal>%P</literal></entry>
- <entry>Unescaped prefix name</entry>
- <entry></entry>
+ <entry><filename>/run/systemd/system</filename></entry>
+ <entry>Runtime units</entry>
</row>
<row>
- <entry><literal>%i</literal></entry>
- <entry>Instance name</entry>
- <entry>This is the string between the @ character and the suffix.</entry>
- </row>
- <row>
- <entry><literal>%I</literal></entry>
- <entry>Unescaped instance name</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%f</literal></entry>
- <entry>Unescaped file name</entry>
- <entry>This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /.</entry>
- </row>
- <row>
- <entry><literal>%c</literal></entry>
- <entry>Control group path of the unit</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%r</literal></entry>
- <entry>Root control group path of systemd</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%R</literal></entry>
- <entry>Parent directory of the root control group path of systemd</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%t</literal></entry>
- <entry>Runtime socket dir</entry>
- <entry>This is either /run (for the system manager) or $XDG_RUNTIME_DIR (for user managers).</entry>
- </row>
- <row>
- <entry><literal>%u</literal></entry>
- <entry>User name</entry>
- <entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ <entry><filename>/usr/lib/systemd/system</filename></entry>
+ <entry>Units of installed packages</entry>
</row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table>
+ <title>
+ Load path when running in user mode (<option>--user</option>).
+ </title>
+
+ <tgroup cols='2'>
+ <colspec colname='path' />
+ <colspec colname='expl' />
+ <thead>
<row>
- <entry><literal>%U</literal></entry>
- <entry>User uid</entry>
- <entry>This is the uid of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ <entry>Path</entry>
+ <entry>Description</entry>
</row>
+ </thead>
+ <tbody>
<row>
- <entry><literal>%h</literal></entry>
- <entry>User home directory</entry>
- <entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ <entry><filename>$HOME/.config/systemd/user</filename></entry>
+ <entry>User configuration</entry>
</row>
<row>
- <entry><literal>%s</literal></entry>
- <entry>User shell</entry>
- <entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ <entry><filename>/etc/systemd/user</filename></entry>
+ <entry>Local configuration</entry>
</row>
<row>
- <entry><literal>%m</literal></entry>
- <entry>Machine ID</entry>
- <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
- </row>
- <row>
- <entry><literal>%b</literal></entry>
- <entry>Boot ID</entry>
- <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
+ <entry><filename>/run/systemd/user</filename></entry>
+ <entry>Runtime units</entry>
</row>
<row>
- <entry><literal>%H</literal></entry>
- <entry>Host name</entry>
- <entry>The host name of the running system.</entry>
+ <entry><filename>/usr/lib/systemd/user</filename></entry>
+ <entry>Units of installed packages</entry>
</row>
</tbody>
</tgroup>
</table>
- <para>If a unit file is empty (i.e. has the file size
- 0) or is symlinked to <filename>/dev/null</filename>
- its configuration will not be loaded and it appears
- with a load state of <literal>masked</literal>, and
- cannot be activated. Use this as an effective way to
- fully disable a unit, making it impossible to start it
- even manually.</para>
-
- <para>The unit file format is covered by the
+ <para>Additional units might be loaded into systemd
+ ("linked") from directories not on the unit load
+ path. See the <command>link</command> command for
+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Also,
+ some units are dynamically created via generators
<ulink
- url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
- Stability Promise</ulink>.</para>
+ url="http://www.freedesktop.org/wiki/Software/systemd/Generators/">Generators</ulink>.
+ </para>
</refsect1>
<refsect1>
carries generic information about the unit that is not
dependent on the type of unit:</para>
- <variablelist>
+ <variablelist class='unit-directives'>
<varlistentry>
<term><varname>Description=</varname></term>
describing the unit. This is intended
for use in UIs to show descriptive
information along with the unit
- name.</para></listitem>
+ name. The description should contain a name
+ that means something to the end user.
+ <literal>Apache2 Web Server</literal> is a good
+ example. Bad examples are
+ <literal>high-performance light-weight HTTP
+ server</literal> (too generic) or
+ <literal>Apache2</literal> (too specific and
+ meaningless for people who do not know
+ Apache).</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>Documentation=</varname></term>
- <listitem><para>A space separated list
+ <listitem><para>A space-separated list
of URIs referencing documentation for
this unit or its
configuration. Accepted are only URIs
<literal>info:</literal>,
<literal>man:</literal>. For more
information about the syntax of these
- URIs see
+ URIs, see
<citerefentry><refentrytitle>uri</refentrytitle><manvolnum>7</manvolnum></citerefentry>. The
URIs should be listed in order of
relevance, starting with the most
reference documentation that explains
what the unit's purpose is, followed
by how it is configured, followed by
- any other related
- documentation.</para></listitem>
+ 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.</para></listitem>
</varlistentry>
<varlistentry>
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
type <varname>After=</varname> or
<varname>Before=</varname>. If two
units have no ordering dependencies
- between them they are shut down
+ between them, they are shut down
or started up simultaneously, and
no ordering takes
place. </para></listitem>
<listitem><para>Lists one or more
units that are activated when this
unit enters the
- '<literal>failed</literal>'
+ <literal>failed</literal>
state.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>RequiresMountsFor=</varname></term>
- <listitem><para>Takes a space
- separated list of absolute paths. Automatically
+ <listitem><para>Takes a space-separated
+ list of absolute paths. Automatically
adds dependencies of type
<varname>Requires=</varname> and
<varname>After=</varname> for all
<term><varname>OnFailureIsolate=</varname></term>
<listitem><para>Takes a boolean
- argument. If <option>true</option> the
+ argument. If <option>true</option>, the
unit listed in
<varname>OnFailure=</varname> will be
enqueued in isolation mode, i.e. all
units that are not its dependency will
- be stopped. If this is set only a
+ be stopped. If this is set, only a
single unit may be listed in
<varname>OnFailure=</varname>. Defaults
to
<term><varname>IgnoreOnIsolate=</varname></term>
<listitem><para>Takes a boolean
- argument. If <option>true</option>
+ argument. If <option>true</option>,
this unit will not be stopped when
isolating another unit. Defaults to
<option>false</option>.</para></listitem>
<term><varname>IgnoreOnSnapshot=</varname></term>
<listitem><para>Takes a boolean
- argument. If <option>true</option>
+ argument. If <option>true</option>,
this unit will not be included in
snapshots. Defaults to
<option>true</option> for device and
<term><varname>StopWhenUnneeded=</varname></term>
<listitem><para>Takes a boolean
- argument. If <option>true</option>
+ argument. If <option>true</option>,
this unit will be stopped when it is
no longer used. Note that in order to
minimize the work to be executed,
<term><varname>RefuseManualStop=</varname></term>
<listitem><para>Takes a boolean
- argument. If <option>true</option>
+ argument. If <option>true</option>,
this unit can only be activated
or deactivated indirectly. In
- this case explicit start-up
+ this case, explicit start-up
or termination requested by the
user is denied, however if it is
started or stopped as a
<term><varname>AllowIsolate=</varname></term>
<listitem><para>Takes a boolean
- argument. If <option>true</option>
+ argument. If <option>true</option>,
this unit may be used with the
<command>systemctl isolate</command>
- 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
<term><varname>DefaultDependencies=</varname></term>
<listitem><para>Takes a boolean
- argument. If <option>true</option>
+ argument. If <option>true</option>,
(the default), a few default
dependencies will implicitly be
created for the unit. The actual
highly recommended to leave this
option enabled for the majority of
common units. If set to
- <option>false</option> this option
+ <option>false</option>, this option
does not disable all implicit
dependencies, just non-essential
ones.</para></listitem>
<listitem><para>When clients are
waiting for a job of this unit to
complete, time out after the specified
- time. If this time limit is reached
+ time. If this time limit is reached,
the job will be cancelled, the unit
however will not change state or even
- enter the '<literal>failed</literal>'
+ enter the <literal>failed</literal>
mode. This value defaults to 0 (job
timeouts disabled), except for device
units. NB: this timeout is independent
<term><varname>ConditionSecurity=</varname></term>
<term><varname>ConditionCapability=</varname></term>
<term><varname>ConditionHost=</varname></term>
+ <term><varname>ConditionACPower=</varname></term>
<term><varname>ConditionNull=</varname></term>
<listitem><para>Before starting a unit
verify that the specified condition is
- true. If it is not true the starting
+ 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
a file existence condition is
checked before a unit is started. If
the specified absolute path name does
- not exist the condition will
+ not exist, the condition will
fail. If the absolute path name passed
to
<varname>ConditionPathExists=</varname>
is prefixed with an exclamation mark
- ('!'), the test is negated, and the unit
+ (<literal>!</literal>), the test is negated, and the unit
is only started if the path does not
exist.</para>
exclamation mark unset). The argument
must either be a single word, or an
assignment (i.e. two words, separated
- '='). In the former
+ <literal>=</literal>). In the former
case the kernel command line is
searched for the word appearing as is,
or as left hand side of an
<varname>xen</varname>,
<varname>bochs</varname>,
<varname>chroot</varname>,
+ <varname>uml</varname>,
<varname>openvz</varname>,
<varname>lxc</varname>,
<varname>lxc-libvirt</varname>,
<varname>systemd-nspawn</varname> to
test against a specific
implementation. If multiple
- virtualization technologies are nested
+ virtualization technologies are nested,
only the innermost is considered. The
test may be negated by prepending an
exclamation mark.</para>
<para><varname>ConditionSecurity=</varname>
may be used to check whether the given
security module is enabled on the
- system. Currently the only recognized
- value is <varname>selinux</varname>.
+ system. Currently the recognized values
+ values are <varname>selinux</varname>,
+ <varname>apparmor</varname>,
+ <varname>ima</varname> and
+ <varname>smack</varname>.
The test may be negated by prepending
an exclamation
mark.</para>
<para><varname>ConditionHost=</varname>
may be used to match against the
- host name or machine ID of the
- host. This either takes a host name
+ 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 host name as returned by
+ locally set hostname as returned by
<citerefentry><refentrytitle>gethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
or a machine ID formatted as string
(see
The test may be negated by prepending
an exclamation mark.</para>
+ <para><varname>ConditionACPower=</varname>
+ 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
+ <varname>true</varname>, 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 <varname>false</varname>, the
+ condition will hold only if there is
+ at least one AC connector known and
+ all AC connectors are disconnected
+ from a power source.</para>
+
<para>Finally,
<varname>ConditionNull=</varname> may
be used to add a constant condition
check value to the unit. It takes a
boolean argument. If set to
- <varname>false</varname> the condition
+ <varname>false</varname>, the condition
will always fail, otherwise
succeed.</para>
<para>If multiple conditions are
- specified the unit will be executed if
+ 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
<varname>ConditionPathIsSymbolicLink=</varname>,
- all path checks follow
- symlinks.</para></listitem>
+ 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.</para></listitem>
</varlistentry>
<varlistentry>
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
tool during installation of a unit:</para>
- <variablelist>
+ <variablelist class='unit-directives'>
<varlistentry>
<term><varname>Alias=</varname></term>
time,
<command>systemctl enable</command>
will create symlinks from these names
- to the unit file name.</para></listitem>
+ to the unit filename.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>WantedBy=</varname></term>
<term><varname>RequiredBy=</varname></term>
- <listitem><para>Installs a symlink in
- the <filename>.wants/</filename>
- or <filename>.requires/</filename>
- subdirectory for a unit, respectively. This has the
- effect that when the listed unit name
- is activated the unit listing it is
- activated
- too. <command>WantedBy=foo.service</command>
+ <listitem><para>A symbolic link is
+ created in the
+ <filename>.wants/</filename> or
+ <filename>.requires/</filename> directory
+ of the listed unit when this unit is
+ activated by <command>systemctl
+ enable</command>. This has the effect
+ that a dependency of type
+ <varname>Wants=</varname> or
+ <varname>Requires=</varname> 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
+ <varname>Wants=</varname> and
+ <varname>Requires=</varname> in the
+ [Unit] section for details.</para>
+
+ <para><command>WantedBy=foo.service</command>
in a service
<filename>bar.service</filename> is
mostly equivalent to
<command>Alias=foo.service.wants/bar.service</command>
- in the same file.</para></listitem>
+ in the same file. In case of template
+ units, <command>systemctl enable</command>
+ must be called with an instance name, and
+ this instance will be added to the
+ <filename>.wants/</filename> or
+ <filename>.requires/</filename> list
+ of the listed unit.
+ E.g. <command>WantedBy=getty.target</command>
+ in a service
+ <filename>getty@.service</filename>
+ will result in <command>systemctl
+ enable getty@tty2.service</command>
+ creating a
+ <filename>getty.target.wants/getty@tty2.service</filename>
+ link to <filename>getty@.service</filename>.
+ </para></listitem>
</varlistentry>
<varlistentry>
<term><varname>Also=</varname></term>
<listitem><para>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,
<command>systemctl enable</command>
- will automatically install units
- listed in this option as
+ and <command>systemctl
+ disable</command> will automatically
+ install/uninstall units listed in this option as
well.</para></listitem>
</varlistentry>
</variablelist>
+ <para>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.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Specifiers</title>
+
+ <para>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:</para>
+
+ <table>
+ <title>Specifiers available in unit files</title>
+ <tgroup cols='3' align='left' colsep='1' rowsep='1'>
+ <colspec colname="spec" />
+ <colspec colname="mean" />
+ <colspec colname="detail" />
+ <thead>
+ <row>
+ <entry>Specifier</entry>
+ <entry>Meaning</entry>
+ <entry>Details</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal>%n</literal></entry>
+ <entry>Full unit name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%N</literal></entry>
+ <entry>Unescaped full unit name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%p</literal></entry>
+ <entry>Prefix name</entry>
+ <entry>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.</entry>
+ </row>
+ <row>
+ <entry><literal>%P</literal></entry>
+ <entry>Unescaped prefix name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%i</literal></entry>
+ <entry>Instance name</entry>
+ <entry>For instantiated units: this is the string between the <literal>@</literal> character and the suffix.</entry>
+ </row>
+ <row>
+ <entry><literal>%I</literal></entry>
+ <entry>Unescaped instance name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%f</literal></entry>
+ <entry>Unescaped filename</entry>
+ <entry>This is either the unescaped instance name (if applicable) with <filename>/</filename> prepended (if applicable), or the prefix name similarly prepended with <filename>/</filename>.</entry>
+ </row>
+ <row>
+ <entry><literal>%c</literal></entry>
+ <entry>Control group path of the unit</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%r</literal></entry>
+ <entry>Root control group path where units are placed.</entry>
+ <entry>For system instances this usually resolves to <filename>/system</filename>, except in containers, where the path might be prefixed with the container's root control group.</entry>
+ </row>
+ <row>
+ <entry><literal>%R</literal></entry>
+ <entry>Parent directory of the control group path where units are placed.</entry>
+ <entry>For system instances this usually resolves to <filename>/</filename>, except in containers, where this resolves to the container's root directory. This specifier is particularly useful in the <varname>ControlGroup=</varname> setting (see <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>).</entry>
+ </row>
+ <row>
+ <entry><literal>%t</literal></entry>
+ <entry>Runtime socket dir</entry>
+ <entry>This is either <filename>/run</filename> (for the system manager) or <literal>$XDG_RUNTIME_DIR</literal> (for user managers).</entry>
+ </row>
+ <row>
+ <entry><literal>%u</literal></entry>
+ <entry>User name</entry>
+ <entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ </row>
+ <row>
+ <entry><literal>%U</literal></entry>
+ <entry>User UID</entry>
+ <entry>This is the UID of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ </row>
+ <row>
+ <entry><literal>%h</literal></entry>
+ <entry>User home directory</entry>
+ <entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ </row>
+ <row>
+ <entry><literal>%s</literal></entry>
+ <entry>User shell</entry>
+ <entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance. If the user is <literal>root</literal> (UID equal to 0), the shell configured in account database is ignored and <filename>/bin/sh</filename> is always used.</entry>
+ </row>
+ <row>
+ <entry><literal>%m</literal></entry>
+ <entry>Machine ID</entry>
+ <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
+ </row>
+ <row>
+ <entry><literal>%b</literal></entry>
+ <entry>Boot ID</entry>
+ <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
+ </row>
+ <row>
+ <entry><literal>%H</literal></entry>
+ <entry>Host name</entry>
+ <entry>The hostname of the running system.</entry>
+ </row>
+ <row>
+ <entry><literal>%v</literal></entry>
+ <entry>Kernel release</entry>
+ <entry>Identical to <command>uname -r</command> output.</entry>
+ </row>
+ <row>
+ <entry><literal>%%</literal></entry>
+ <entry>Escaped %</entry>
+ <entry>Single percent sign.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
</refsect1>
<refsect1>
<citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>uname</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff