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diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml deleted file mode 100644 index 40c4cfd854..0000000000 --- a/man/systemd.unit.xml +++ /dev/null @@ -1,1493 +0,0 @@ -<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> -<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" - "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ -<!ENTITY % entities SYSTEM "custom-entities.ent" > -%entities; -]> - -<!-- - This file is part of systemd. - - Copyright 2010 Lennart Poettering - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. ---> - -<refentry id="systemd.unit"> - - <refentryinfo> - <title>systemd.unit</title> - <productname>systemd</productname> - - <authorgroup> - <author> - <contrib>Developer</contrib> - <firstname>Lennart</firstname> - <surname>Poettering</surname> - <email>lennart@poettering.net</email> - </author> - </authorgroup> - </refentryinfo> - - <refmeta> - <refentrytitle>systemd.unit</refentrytitle> - <manvolnum>5</manvolnum> - </refmeta> - - <refnamediv> - <refname>systemd.unit</refname> - <refpurpose>Unit configuration</refpurpose> - </refnamediv> - - <refsynopsisdiv> - <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>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>~/.config/systemd/user/*</filename> -<filename>/etc/systemd/user/*</filename> -<filename>$XDG_RUNTIME_DIR/systemd/user/*</filename> -<filename>/run/systemd/user/*</filename> -<filename>~/.local/share/systemd/user/*</filename> -<filename>/usr/lib/systemd/user/*</filename> -<filename>…</filename> - </literallayout></para> - </refsynopsisdiv> - - <refsect1> - <title>Description</title> - - <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 watched file system - path, a timer controlled and supervised by - <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - 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 inspired by Microsoft Windows - <filename>.ini</filename> files.</para> - - <para>This man page lists the common configuration options of all - the unit types. These options need to be configured in the [Unit] - or [Install] sections of the unit files.</para> - - <para>In addition to the generic [Unit] and [Install] sections - described here, each unit may have a type-specific section, e.g. - [Service] for a service unit. See the respective man pages for - more information: - <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.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>, - <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>. - </para> - - <para>Various settings are allowed to be specified more than once, - in which case the interpretation depends on the setting. Often, - multiple settings form a list, and setting to an empty value - "resets", which means that previous assignments are ignored. When - this is allowed, it is mentioned in the description of the - setting. Note that using multiple assignments to the same value - makes the unit file incompatible with parsers for the XDG - <filename>.desktop</filename> file format.</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 continue loading the unit. If an - option or section name is prefixed with <option>X-</option>, it is - ignored completely by systemd. Options within an ignored section - do not need the prefix. Applications may use this to include - additional information in the unit files.</para> - - <para>Boolean arguments used in unit files can be 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 <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: <literal>50</literal> refers to 50 seconds; <literal>2min 200ms</literal> refers to - 2 minutes and 200 milliseconds, i.e. 120200 ms. The following time units are understood: - <literal>s</literal>, <literal>min</literal>, <literal>h</literal>, <literal>d</literal>, - <literal>w</literal>, <literal>ms</literal>, <literal>us</literal>. For details see - <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> - - <para>Empty lines and lines starting with <literal>#</literal> or <literal>;</literal> are - ignored. This may be used for commenting. Lines ending in a backslash are concatenated with the - following line while reading and the backslash is replaced by a space character. This may be - used to wrap long lines.</para> - - <para>Units can be aliased (have an alternative name), by creating a symlink from the new name - to the existing name in one of the unit search paths. For example, - <filename>systemd-networkd.service</filename> has the alias - <filename>dbus-org.freedesktop.network1.service</filename>, created during installation as the - symlink <filename>/usr/lib/systemd/system/dbus-org.freedesktop.network1.service</filename>. In - addition, unit files may specify aliases through the <varname>Alias=</varname> directive in the - [Install] section; those aliases are only effective when the unit is enabled. When the unit is - enabled, symlinks will be created for those names, and removed when the unit is disabled. For - example, <filename>reboot.target</filename> specifies - <varname>Alias=ctrl-alt-del.target</varname>, so when enabled it will be invoked whenever - CTRL+ALT+DEL is pressed. Alias names may be used in commands like <command>enable</command>, - <command>disable</command>, <command>start</command>, <command>stop</command>, - <command>status</command>, …, and in unit dependency directives <varname>Wants=</varname>, - <varname>Requires=</varname>, <varname>Before=</varname>, <varname>After=</varname>, …, with the - limitation that aliases specified through <varname>Alias=</varname> are only effective when the - unit is enabled. Aliases cannot be used with the <command>preset</command> command.</para> - - <para>Along with a unit file <filename>foo.service</filename>, the directory - <filename>foo.service.wants/</filename> may exist. All unit files symlinked from such a - directory are implicitly added as dependencies of type <varname>Wants=</varname> to the unit. - This is useful to hook units into the start-up of other units, without having to modify their - unit files. For details about the semantics of <varname>Wants=</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 - 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 "drop-in" 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 for a unit, without having to - modify unit files. Each drop-in file must have appropriate section headers. Note that for - instantiated units, this logic will first look for the instance <literal>.d/</literal> - subdirectory and read its <literal>.conf</literal> files, followed by the template - <literal>.d/</literal> subdirectory and the <literal>.conf</literal> files there. Also note that - settings from the <literal>[Install]</literal> section are not honored in drop-in unit files, - and have no effect.</para> - - <para>In addition to <filename>/etc/systemd/system</filename>, the drop-in <literal>.d</literal> - directories for system services can be placed in <filename>/usr/lib/systemd/system</filename> or - <filename>/run/systemd/system</filename> directories. Drop-in files in <filename>/etc</filename> - take precedence over those in <filename>/run</filename> which in turn take precedence over those - in <filename>/usr/lib</filename>. Drop-in files under any of these directories take precedence - over unit files wherever located.</para> - - <!-- Note that we do not document .include here, as we consider it mostly obsolete, and want - people to use .d/ drop-ins instead. --> - - <para>Some unit names reflect paths existing in the file system - namespace. Example: a device unit - <filename>dev-sda.device</filename> refers to a device 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 - 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 - <citerefentry><refentrytitle>systemd-escape</refentrytitle><manvolnum>1</manvolnum></citerefentry> - command.</para> - - <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 - first search for the literal unit name in the - file system. If that yields no success and the unit - 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 <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 - for <filename>getty@.service</filename> and - instantiate a service from that configuration file if - it is found.</para> - - <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. 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>Automatic Dependencies</title> - - <para>Note that while systemd offers a flexible dependency system - between units it is recommended to use this functionality only - sparingly and instead rely on techniques such as bus-based or - socket-based activation which make dependencies implicit, - resulting in a both simpler and more flexible system.</para> - - <para>A number of unit dependencies are automatically established, - depending on unit configuration. On top of that, for units with - <varname>DefaultDependencies=yes</varname> (the default) a couple - of additional dependencies are added. The precise effect of - <varname>DefaultDependencies=yes</varname> depends on the unit - type (see below).</para> - - <para>If <varname>DefaultDependencies=yes</varname> is set, units - that are referenced by other units of type - <filename>.target</filename> via a <varname>Wants=</varname> or - <varname>Requires=</varname> dependency might automatically gain - an <varname>Before=</varname> dependency too. See - <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry> - for details.</para> - </refsect1> - - <refsect1> - <title>Unit File 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 the variable <varname>$SYSTEMD_UNIT_PATH</varname> is set, - the contents of this variable overrides the unit load path. If - <varname>$SYSTEMD_UNIT_PATH</varname> ends with an empty component - (<literal>:</literal>), the usual unit load path will be appended - to the contents of the variable.</para> - - <table> - <title> - Load path when running in system mode (<option>--system</option>). - </title> - - <tgroup cols='2'> - <colspec colname='path' /> - <colspec colname='expl' /> - <thead> - <row> - <entry>Path</entry> - <entry>Description</entry> - </row> - </thead> - <tbody> - <row> - <entry><filename>/etc/systemd/system</filename></entry> - <entry>Local configuration</entry> - </row> - <row> - <entry><filename>/run/systemd/system</filename></entry> - <entry>Runtime units</entry> - </row> - <row> - <entry><filename>/usr/lib/systemd/system</filename></entry> - <entry>Units of installed packages</entry> - </row> - </tbody> - </tgroup> - </table> - - <table> - <title> - Load path when running in user mode (<option>--user</option>). - </title> - - <tgroup cols='2'> - <colspec colname='path' /> - <colspec colname='expl' /> - <thead> - <row> - <entry>Path</entry> - <entry>Description</entry> - </row> - </thead> - <tbody> - <row> - <entry><filename>$XDG_CONFIG_HOME/systemd/user</filename></entry> - <entry>User configuration (only used when $XDG_CONFIG_HOME is set)</entry> - </row> - <row> - <entry><filename>$HOME/.config/systemd/user</filename></entry> - <entry>User configuration (only used when $XDG_CONFIG_HOME is not set)</entry> - </row> - <row> - <entry><filename>/etc/systemd/user</filename></entry> - <entry>Local configuration</entry> - </row> - <row> - <entry><filename>$XDG_RUNTIME_DIR/systemd/user</filename></entry> - <entry>Runtime units (only used when $XDG_RUNTIME_DIR is set)</entry> - </row> - <row> - <entry><filename>/run/systemd/user</filename></entry> - <entry>Runtime units</entry> - </row> - <row> - <entry><filename>$XDG_DATA_HOME/systemd/user</filename></entry> - <entry>Units of packages that have been installed in the home directory (only used when $XDG_DATA_HOME is set)</entry> - </row> - <row> - <entry><filename>$HOME/.local/share/systemd/user</filename></entry> - <entry>Units of packages that have been installed in the home directory (only used when $XDG_DATA_HOME is not set)</entry> - </row> - <row> - <entry><filename>/usr/lib/systemd/user</filename></entry> - <entry>Units of packages that have been installed system-wide</entry> - </row> - </tbody> - </tgroup> - </table> - - <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 a - <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>. - </para> - </refsect1> - - <refsect1> - <title>[Unit] Section Options</title> - - <para>The unit file may include a [Unit] section, which carries - generic information about the unit that is not dependent on the - type of unit:</para> - - <variablelist class='unit-directives'> - - <varlistentry> - <term><varname>Description=</varname></term> - <listitem><para>A free-form string describing the unit. This - is intended for use in UIs to show descriptive information - along with the unit name. The description should contain a - name that means something to the end user. <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 of URIs referencing - documentation for this unit or its configuration. Accepted are - only URIs of the types <literal>http://</literal>, - <literal>https://</literal>, <literal>file:</literal>, - <literal>info:</literal>, <literal>man:</literal>. For more - information about the syntax of these URIs, see <citerefentry - project='man-pages'><refentrytitle>uri</refentrytitle><manvolnum>7</manvolnum></citerefentry>. - 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.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>Requires=</varname></term> - - <listitem><para>Configures requirement dependencies on other - units. If this unit gets activated, the units listed here will - be activated as well. If one of the other units gets - deactivated or its activation fails, this unit will be - deactivated. This option may be specified more than once or - multiple space-separated units may be specified in one option - in which case requirement dependencies for all listed names - will be created. Note that requirement dependencies do not - influence the order in which services are started or stopped. - This has to be configured independently with the - <varname>After=</varname> or <varname>Before=</varname> - options. If a unit <filename>foo.service</filename> requires a - unit <filename>bar.service</filename> as configured with - <varname>Requires=</varname> and no ordering is configured - with <varname>After=</varname> or <varname>Before=</varname>, - then both units will be started simultaneously and without any - delay between them if <filename>foo.service</filename> is - activated. Often, it is a better choice to use - <varname>Wants=</varname> instead of - <varname>Requires=</varname> in order to achieve a system that - is more robust when dealing with failing services.</para> - - <para>Note that dependencies of this type may also be - configured outside of the unit configuration file by adding a - symlink to a <filename>.requires/</filename> directory - accompanying the unit file. For details, see - above.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>Requisite=</varname></term> - - <listitem><para>Similar to <varname>Requires=</varname>. - However, if the units listed here are not started already, - they will not be started and the transaction will fail - immediately. </para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>Wants=</varname></term> - - <listitem><para>A weaker version of - <varname>Requires=</varname>. Units listed in this option will - be started if the configuring unit is. However, if the listed - units fail to start or cannot be added to the transaction, - this has no impact on the validity of the transaction as a - whole. This is the recommended way to hook start-up of one - unit to the start-up of another unit.</para> - - <para>Note that dependencies of this type may also be - configured outside of the unit configuration file by adding - symlinks to a <filename>.wants/</filename> directory - accompanying the unit file. For details, see - above.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>BindsTo=</varname></term> - - <listitem><para>Configures requirement dependencies, very - similar in style to <varname>Requires=</varname>, however in - addition to this behavior, it also declares that this unit is - stopped when any of the units listed suddenly disappears. - Units can suddenly, unexpectedly disappear if a service - terminates on its own choice, a device is unplugged or a mount - point unmounted without involvement of - systemd.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>PartOf=</varname></term> - - <listitem><para>Configures dependencies similar to - <varname>Requires=</varname>, 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. </para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>Conflicts=</varname></term> - - <listitem><para>A space-separated list of unit names. - Configures negative requirement dependencies. If a unit has a - <varname>Conflicts=</varname> 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 - <varname>After=</varname> and <varname>Before=</varname> - ordering dependencies.</para> - - <para>If a unit A that conflicts with a unit B is scheduled to - be started at the same time as B, the transaction will either - fail (in case both are required part of the transaction) or be - modified to be fixed (in case one or both jobs are not a - required part of the transaction). In the latter case, the job - that is not the required will be removed, or in case both are - not required, the unit that conflicts will be started and the - unit that is conflicted is stopped.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>Before=</varname></term> - <term><varname>After=</varname></term> - - <listitem><para>A space-separated list of unit names. - Configures ordering dependencies between units. If a unit - <filename>foo.service</filename> contains a setting - <option>Before=bar.service</option> and both units are being - started, <filename>bar.service</filename>'s start-up is - delayed until <filename>foo.service</filename> is started up. - Note that this setting is independent of and orthogonal to the - requirement dependencies as configured by - <varname>Requires=</varname>. It is a common pattern to - include a unit name in both the <varname>After=</varname> and - <varname>Requires=</varname> option, in which case the unit - listed will be started before the unit that is configured with - these options. This option may be specified more than once, in - which case ordering dependencies for all listed names are - created. <varname>After=</varname> is the inverse of - <varname>Before=</varname>, i.e. while - <varname>After=</varname> ensures that the configured unit is - started after the listed unit finished starting up, - <varname>Before=</varname> ensures the opposite, i.e. that the - configured unit is fully started up before the listed unit is - started. Note that when two units with an ordering dependency - between them are shut down, the inverse of the start-up order - is applied. i.e. if a unit is configured with - <varname>After=</varname> on another unit, the former is - stopped before the latter if both are shut down. Given two units - with any ordering dependency between them, if one unit is shut - down and the other is started up, the shutdown is ordered - before the start-up. It doesn't matter if the ordering - dependency is <varname>After=</varname> or - <varname>Before=</varname>. It also doesn't matter which of the - two is shut down, as long as one is shut down and the other is - started up. The shutdown is ordered before the start-up in all - cases. If two units have no ordering dependencies between them, - they are shut down or started up simultaneously, and no ordering - takes place. - </para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>OnFailure=</varname></term> - - <listitem><para>A space-separated list of one or more units - that are activated when this unit enters the - <literal>failed</literal> state.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>PropagatesReloadTo=</varname></term> - <term><varname>ReloadPropagatedFrom=</varname></term> - - <listitem><para>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.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>JoinsNamespaceOf=</varname></term> - - <listitem><para>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 - <varname>PrivateNetwork=</varname> and - <varname>PrivateTmp=</varname> directives (see - <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> - for details). If a unit that has this setting set is started, - its processes will see the same <filename>/tmp</filename>, - <filename>/var/tmp</filename> 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 - <varname>PrivateNetwork=</varname> and/or - <varname>PrivateTmp=</varname> is enabled for both the unit - that joins the namespace and the unit whose namespace is - joined.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>RequiresMountsFor=</varname></term> - - <listitem><para>Takes a space-separated list of absolute - paths. Automatically adds dependencies of type - <varname>Requires=</varname> and <varname>After=</varname> for - all mount units required to access the specified path.</para> - - <para>Mount points marked with <option>noauto</option> 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 - (<varname>Requires=</varname> and <varname>After=</varname> or - some other combination). </para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>OnFailureJobMode=</varname></term> - - <listitem><para>Takes a value of - <literal>fail</literal>, - <literal>replace</literal>, - <literal>replace-irreversibly</literal>, - <literal>isolate</literal>, - <literal>flush</literal>, - <literal>ignore-dependencies</literal> or - <literal>ignore-requirements</literal>. Defaults to - <literal>replace</literal>. Specifies how the units listed in - <varname>OnFailure=</varname> will be enqueued. See - <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s - <option>--job-mode=</option> option for details on the - possible values. If this is set to <literal>isolate</literal>, - only a single unit may be listed in - <varname>OnFailure=</varname>..</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>IgnoreOnIsolate=</varname></term> - - <listitem><para>Takes a boolean argument. If - <option>true</option>, this unit will not be stopped when - isolating another unit. Defaults to - <option>false</option>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>StopWhenUnneeded=</varname></term> - - <listitem><para>Takes a boolean 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, systemd will not stop units by default unless they - are conflicting with other units, or the user explicitly - requested their shut down. If this option is set, a unit will - be automatically cleaned up if no other active unit requires - it. Defaults to <option>false</option>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>RefuseManualStart=</varname></term> - <term><varname>RefuseManualStop=</varname></term> - - <listitem><para>Takes a boolean argument. If - <option>true</option>, this unit can only be activated or - deactivated indirectly. In this case, explicit start-up or - termination requested by the user is denied, however if it is - started or stopped as a dependency of another unit, start-up - or termination will succeed. This is mostly a safety feature - to ensure that the user does not accidentally activate units - that are not intended to be activated explicitly, and not - accidentally deactivate units that are not intended to be - deactivated. These options default to - <option>false</option>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>AllowIsolate=</varname></term> - - <listitem><para>Takes a boolean argument. If - <option>true</option>, this unit may be used with the - <command>systemctl isolate</command> command. Otherwise, this - will be refused. It probably is a good idea to leave this - disabled except for target units that shall be used similar to - runlevels in SysV init systems, just as a precaution to avoid - unusable system states. This option defaults to - <option>false</option>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>DefaultDependencies=</varname></term> - - <listitem><para>Takes a boolean argument. If - <option>true</option>, (the default), a few default - dependencies will implicitly be created for the unit. The - actual dependencies created depend on the unit type. For - example, for service units, these dependencies ensure that the - service is started only after basic system initialization is - completed and is properly terminated on system shutdown. See - the respective man pages for details. Generally, only services - involved with early boot or late shutdown should set this - option to <option>false</option>. It is highly recommended to - leave this option enabled for the majority of common units. If - set to <option>false</option>, this option does not disable - all implicit dependencies, just non-essential - ones.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>JobTimeoutSec=</varname></term> - <term><varname>JobTimeoutAction=</varname></term> - <term><varname>JobTimeoutRebootArgument=</varname></term> - - <listitem><para>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 - <literal>failed</literal> mode. This value defaults to <literal>infinity</literal> (job timeouts disabled), - except for device units. NB: this timeout is independent from any unit-specific timeout (for example, the - timeout set with <varname>TimeoutStartSec=</varname> in service units) as the job timeout has no effect on the - unit itself, only on the job that might be pending for it. Or in other words: unit-specific timeouts are useful - to abort unit state changes, and revert them. The job timeout set with this option however is useful to abort - only the job waiting for the unit state to change.</para> - - <para><varname>JobTimeoutAction=</varname> - optionally configures an additional - action to take when the time-out is - hit. It takes the same values as the - per-service - <varname>StartLimitAction=</varname> - setting, see - <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> - for details. Defaults to - <option>none</option>. <varname>JobTimeoutRebootArgument=</varname> - configures an optional reboot string - to pass to the - <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry> - system call.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>StartLimitIntervalSec=</varname></term> - <term><varname>StartLimitBurst=</varname></term> - - <listitem><para>Configure unit start rate limiting. By default, units which are started more than 5 times - within 10 seconds are not permitted to start any more times until the 10 second interval ends. With these two - options, this rate limiting may be modified. Use <varname>StartLimitIntervalSec=</varname> to configure the - checking interval (defaults to <varname>DefaultStartLimitIntervalSec=</varname> in manager configuration file, - set to 0 to disable any kind of rate limiting). Use <varname>StartLimitBurst=</varname> to configure how many - starts per interval are allowed (defaults to <varname>DefaultStartLimitBurst=</varname> in manager - configuration file). These configuration options are particularly useful in conjunction with the service - setting <varname>Restart=</varname> (see - <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>); however, - they apply to all kinds of starts (including manual), not just those triggered by the - <varname>Restart=</varname> logic. Note that units which are configured for <varname>Restart=</varname> and - which reach the start limit are not attempted to be restarted anymore; however, they may still be restarted - manually at a later point, from which point on, the restart logic is again activated. Note that - <command>systemctl reset-failed</command> will cause the restart rate counter for a service to be flushed, - which is useful if the administrator wants to manually start a unit and the start limit interferes with - that. Note that this rate-limiting is enforced after any unit condition checks are executed, and hence unit - activations with failing conditions are not counted by this rate limiting. Slice, target, device and scope - units do not enforce this setting, as they are unit types whose activation may either never fail, or may - succeed only a single time.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>StartLimitAction=</varname></term> - - <listitem><para>Configure the action to take if the rate limit configured with - <varname>StartLimitIntervalSec=</varname> and <varname>StartLimitBurst=</varname> is hit. Takes one of - <option>none</option>, <option>reboot</option>, <option>reboot-force</option>, - <option>reboot-immediate</option>, <option>poweroff</option>, <option>poweroff-force</option> or - <option>poweroff-immediate</option>. If <option>none</option> is set, hitting the rate limit will trigger no - action besides that the start will not be permitted. <option>reboot</option> causes a reboot following the - normal shutdown procedure (i.e. equivalent to <command>systemctl reboot</command>). - <option>reboot-force</option> causes a forced reboot which will terminate all processes forcibly but should - cause no dirty file systems on reboot (i.e. equivalent to <command>systemctl reboot -f</command>) and - <option>reboot-immediate</option> causes immediate execution of the - <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call, which - might result in data loss. Similarly, <option>poweroff</option>, <option>poweroff-force</option>, - <option>poweroff-immediate</option> have the effect of powering down the system with similar - semantics. Defaults to <option>none</option>.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>RebootArgument=</varname></term> - <listitem><para>Configure the optional argument for the - <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call if - <varname>StartLimitAction=</varname> or a service's <varname>FailureAction=</varname> is a reboot action. This - works just like the optional argument to <command>systemctl reboot</command> command.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>ConditionArchitecture=</varname></term> - <term><varname>ConditionVirtualization=</varname></term> - <term><varname>ConditionHost=</varname></term> - <term><varname>ConditionKernelCommandLine=</varname></term> - <term><varname>ConditionSecurity=</varname></term> - <term><varname>ConditionCapability=</varname></term> - <term><varname>ConditionACPower=</varname></term> - <term><varname>ConditionNeedsUpdate=</varname></term> - <term><varname>ConditionFirstBoot=</varname></term> - <term><varname>ConditionPathExists=</varname></term> - <term><varname>ConditionPathExistsGlob=</varname></term> - <term><varname>ConditionPathIsDirectory=</varname></term> - <term><varname>ConditionPathIsSymbolicLink=</varname></term> - <term><varname>ConditionPathIsMountPoint=</varname></term> - <term><varname>ConditionPathIsReadWrite=</varname></term> - <term><varname>ConditionDirectoryNotEmpty=</varname></term> - <term><varname>ConditionFileNotEmpty=</varname></term> - <term><varname>ConditionFileIsExecutable=</varname></term> - - <!-- We do not document ConditionNull= - here, as it is not particularly - useful and probably just - confusing. --> - - <listitem><para>Before starting a unit, verify that the specified condition is true. If it is not true, the - starting of the unit will be (mostly silently) 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. Use condition expressions in order to silently skip - units that do not apply to the local running system, for example because the kernel or runtime environment - doesn't require its functionality. Use the various <varname>AssertArchitecture=</varname>, - <varname>AssertVirtualization=</varname>, … options for a similar mechanism that puts the unit in a failure - state and logs about the failed check (see below).</para> - - <para><varname>ConditionArchitecture=</varname> may be used to - check whether the system is running on a specific - architecture. Takes one of - <varname>x86</varname>, - <varname>x86-64</varname>, - <varname>ppc</varname>, - <varname>ppc-le</varname>, - <varname>ppc64</varname>, - <varname>ppc64-le</varname>, - <varname>ia64</varname>, - <varname>parisc</varname>, - <varname>parisc64</varname>, - <varname>s390</varname>, - <varname>s390x</varname>, - <varname>sparc</varname>, - <varname>sparc64</varname>, - <varname>mips</varname>, - <varname>mips-le</varname>, - <varname>mips64</varname>, - <varname>mips64-le</varname>, - <varname>alpha</varname>, - <varname>arm</varname>, - <varname>arm-be</varname>, - <varname>arm64</varname>, - <varname>arm64-be</varname>, - <varname>sh</varname>, - <varname>sh64</varname>, - <varname>m86k</varname>, - <varname>tilegx</varname>, - <varname>cris</varname> to test - against a specific architecture. The architecture is - determined from the information returned by - <citerefentry project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> - and is thus subject to - <citerefentry><refentrytitle>personality</refentrytitle><manvolnum>2</manvolnum></citerefentry>. - Note that a <varname>Personality=</varname> setting in the - same unit file has no effect on this condition. A special - architecture name <varname>native</varname> is mapped to the - architecture the system manager itself is compiled for. The - test may be negated by prepending an exclamation mark.</para> - - <para><varname>ConditionVirtualization=</varname> may be used - to check whether the system is executed in a virtualized - environment and optionally test whether it is a specific - implementation. Takes either boolean value to check if being - executed in any virtualized environment, or one of - <varname>vm</varname> and - <varname>container</varname> to test against a generic type of - virtualization solution, or one of - <varname>qemu</varname>, - <varname>kvm</varname>, - <varname>zvm</varname>, - <varname>vmware</varname>, - <varname>microsoft</varname>, - <varname>oracle</varname>, - <varname>xen</varname>, - <varname>bochs</varname>, - <varname>uml</varname>, - <varname>openvz</varname>, - <varname>lxc</varname>, - <varname>lxc-libvirt</varname>, - <varname>systemd-nspawn</varname>, - <varname>docker</varname>, - <varname>rkt</varname> to test - against a specific implementation, or - <varname>private-users</varname> to check whether we are running in a user namespace. See - <citerefentry><refentrytitle>systemd-detect-virt</refentrytitle><manvolnum>1</manvolnum></citerefentry> - 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.</para> - - <para><varname>ConditionHost=</varname> 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 - <citerefentry><refentrytitle>gethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry>, - or a machine ID formatted as string (see - <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>). - The test may be negated by prepending an exclamation - mark.</para> - - <para><varname>ConditionKernelCommandLine=</varname> 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 <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 assignment. In the latter case, - the exact assignment is looked for with right and left hand - side matching.</para> - - <para><varname>ConditionSecurity=</varname> may be used to - check whether the given security module is enabled on the - system. Currently, the recognized values are - <varname>selinux</varname>, - <varname>apparmor</varname>, - <varname>ima</varname>, - <varname>smack</varname> and - <varname>audit</varname>. The test may be negated by - prepending an exclamation mark.</para> - - <para><varname>ConditionCapability=</varname> 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 - <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> - for details). Pass a capability name such as - <literal>CAP_MKNOD</literal>, possibly prefixed with an - exclamation mark to negate the check.</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><varname>ConditionNeedsUpdate=</varname> takes one of - <filename>/var</filename> or <filename>/etc</filename> as - argument, possibly prefixed with a <literal>!</literal> (for - inverting the condition). This condition may be used to - conditionalize units on whether the specified directory - requires an update because <filename>/usr</filename>'s - modification time is newer than the stamp file - <filename>.updated</filename> in the specified directory. This - is useful to implement offline updates of the vendor operating - system resources in <filename>/usr</filename> that require - updating of <filename>/etc</filename> or - <filename>/var</filename> on the next following boot. Units - making use of this condition should order themselves before - <citerefentry><refentrytitle>systemd-update-done.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, - to make sure they run before the stamp file's modification - time gets reset indicating a completed update.</para> - - <para><varname>ConditionFirstBoot=</varname> takes a boolean - argument. This condition may be used to conditionalize units - on whether the system is booting up with an unpopulated - <filename>/etc</filename> directory. This may be used to - populate <filename>/etc</filename> on the first boot after - factory reset, or when a new system instances boots up for the - first time.</para> - - <para>With <varname>ConditionPathExists=</varname> 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 - <varname>ConditionPathExists=</varname> is prefixed with an - exclamation mark (<literal>!</literal>), the test is negated, - and the unit is only started if the path does not - exist.</para> - - <para><varname>ConditionPathExistsGlob=</varname> is similar - to <varname>ConditionPathExists=</varname>, but checks for the - existence of at least one file or directory matching the - specified globbing pattern.</para> - - <para><varname>ConditionPathIsDirectory=</varname> is similar - to <varname>ConditionPathExists=</varname> but verifies - whether a certain path exists and is a directory.</para> - - <para><varname>ConditionPathIsSymbolicLink=</varname> is - similar to <varname>ConditionPathExists=</varname> but - verifies whether a certain path exists and is a symbolic - link.</para> - - <para><varname>ConditionPathIsMountPoint=</varname> is similar - to <varname>ConditionPathExists=</varname> but verifies - whether a certain path exists and is a mount point.</para> - - <para><varname>ConditionPathIsReadWrite=</varname> is similar - to <varname>ConditionPathExists=</varname> but verifies - whether the underlying file system is readable and writable - (i.e. not mounted read-only).</para> - - <para><varname>ConditionDirectoryNotEmpty=</varname> is - similar to <varname>ConditionPathExists=</varname> but - verifies whether a certain path exists and is a non-empty - directory.</para> - - <para><varname>ConditionFileNotEmpty=</varname> is similar to - <varname>ConditionPathExists=</varname> but verifies whether a - certain path exists and refers to a regular file with a - non-zero size.</para> - - <para><varname>ConditionFileIsExecutable=</varname> is similar - to <varname>ConditionPathExists=</varname> but verifies - whether a certain path exists, is a regular file and marked - executable.</para> - - <para>If multiple conditions are specified, the unit will be - executed if all of them apply (i.e. a logical AND is applied). - Condition checks can be prefixed with a pipe symbol (|) in - which case a condition becomes a triggering condition. If at - least one triggering condition is defined for a unit, then the - unit will be executed if at least one of the triggering - conditions apply and all of the non-triggering conditions. If - you prefix an argument with the pipe symbol and an exclamation - mark, the pipe symbol must be passed first, the exclamation - second. Except for - <varname>ConditionPathIsSymbolicLink=</varname>, 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> - <term><varname>AssertArchitecture=</varname></term> - <term><varname>AssertVirtualization=</varname></term> - <term><varname>AssertHost=</varname></term> - <term><varname>AssertKernelCommandLine=</varname></term> - <term><varname>AssertSecurity=</varname></term> - <term><varname>AssertCapability=</varname></term> - <term><varname>AssertACPower=</varname></term> - <term><varname>AssertNeedsUpdate=</varname></term> - <term><varname>AssertFirstBoot=</varname></term> - <term><varname>AssertPathExists=</varname></term> - <term><varname>AssertPathExistsGlob=</varname></term> - <term><varname>AssertPathIsDirectory=</varname></term> - <term><varname>AssertPathIsSymbolicLink=</varname></term> - <term><varname>AssertPathIsMountPoint=</varname></term> - <term><varname>AssertPathIsReadWrite=</varname></term> - <term><varname>AssertDirectoryNotEmpty=</varname></term> - <term><varname>AssertFileNotEmpty=</varname></term> - <term><varname>AssertFileIsExecutable=</varname></term> - - <listitem><para>Similar to the <varname>ConditionArchitecture=</varname>, - <varname>ConditionVirtualization=</varname>, …, 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 (which means this is logged loudly). Use assertion - expressions for units that cannot operate when specific requirements are not met, and when this is something - the administrator or user should look into.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>SourcePath=</varname></term> - <listitem><para>A path to a configuration file this unit has - been generated from. This is primarily useful for - implementation of generator tools that convert configuration - from an external configuration file format into native unit - files. This functionality should not be used in normal - units.</para></listitem> - </varlistentry> - - </variablelist> - - </refsect1> - - <refsect1> - <title>[Install] Section Options</title> - - <para>Unit files may include an <literal>[Install]</literal> section, which carries installation information for - the unit. This section is not interpreted by - <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> during runtime; it is - used by the <command>enable</command> and <command>disable</command> commands of the - <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> tool during - installation of a unit. Note that settings in the <literal>[Install]</literal> section may not appear in - <filename>.d/*.conf</filename> unit file drop-ins (see above).</para> - - <variablelist class='unit-directives'> - <varlistentry> - <term><varname>Alias=</varname></term> - - <listitem><para>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, <command>systemctl enable</command> will create - symlinks from these names to the unit filename. Note that not all unit types support such alias names, and this - setting is not supported for them. Specifically, mount, slice, swap, and automount units do not support - aliasing.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>WantedBy=</varname></term> - <term><varname>RequiredBy=</varname></term> - - <listitem><para>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 <filename>.wants/</filename> or - <filename>.requires/</filename> directory of each of the - listed units when this unit is installed 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. 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/deinstall when - this unit is installed/deinstalled. If the user requests - installation/deinstallation of a unit with this option - configured, <command>systemctl enable</command> and - <command>systemctl disable</command> will automatically - install/uninstall units listed in this option as well.</para> - - <para>This option may be used more than once, or a - space-separated list of unit names may be - given.</para></listitem> - </varlistentry> - - <varlistentry> - <term><varname>DefaultInstance=</varname></term> - - <listitem><para>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.</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>Same as <literal>%n</literal>, but with escaping undone</entry> - </row> - <row> - <entry><literal>%p</literal></entry> - <entry>Prefix name</entry> - <entry>For instantiated units, this refers to the string before the <literal>@</literal> character of the unit name. For non-instantiated units, this refers 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>Same as <literal>%p</literal>, but with escaping undone</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 of the unit name.</entry> - </row> - <row> - <entry><literal>%I</literal></entry> - <entry>Unescaped instance name</entry> - <entry>Same as <literal>%i</literal>, but with escaping undone</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 unescaped prefix name prepended with <filename>/</filename>.</entry> - </row> - <row> - <entry><literal>%c</literal></entry> - <entry>Control group path of the unit</entry> - <entry>This path does not include the <filename>/sys/fs/cgroup/systemd/</filename> prefix.</entry> - </row> - <row> - <entry><literal>%r</literal></entry> - <entry>Control group path of the slice the unit is placed in</entry> - <entry>This usually maps to the parent control group path of <literal>%c</literal>.</entry> - </row> - <row> - <entry><literal>%R</literal></entry> - <entry>Root control group path below which slices and units are placed</entry> - <entry>For system instances, this resolves to <filename>/</filename>, except in containers, where this maps to the container's root control group path.</entry> - </row> - <row> - <entry><literal>%t</literal></entry> - <entry>Runtime directory</entry> - <entry>This is either <filename>/run</filename> (for the system manager) or the path <literal>$XDG_RUNTIME_DIR</literal> resolves to (for user managers).</entry> - </row> - <row> - <entry><literal>%u</literal></entry> - <entry>User name</entry> - <entry>This is the name of the user running the service manager instance. In case of the system manager this resolves to <literal>root</literal>.</entry> - </row> - <row> - <entry><literal>%U</literal></entry> - <entry>User UID</entry> - <entry>This is the numeric UID of the user running the service manager instance. In case of the system manager this resolves to <literal>0</literal>.</entry> - </row> - <row> - <entry><literal>%h</literal></entry> - <entry>User home directory</entry> - <entry>This is the home directory of the user running the service manager instance. In case of the system manager this resolves to <literal>/root</literal>.</entry> - </row> - <row> - <entry><literal>%s</literal></entry> - <entry>User shell</entry> - <entry>This is the shell of the user running the service manager instance. In case of the system manager this resolves to <literal>/bin/sh</literal>.</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 at the point in time the unit configuration is loaded.</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>Single percent sign</entry> - <entry>Use <literal>%%</literal> in place of <literal>%</literal> to specify a single percent sign.</entry> - </row> - </tbody> - </tgroup> - </table> - - <para>Please note that specifiers <literal>%U</literal>, - <literal>%h</literal>, <literal>%s</literal> 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 <option>--user</option> mode.</para> - </refsect1> - - <refsect1> - <title>Examples</title> - - <example> - <title>Allowing units to be enabled</title> - - <para>The following snippet (highlighted) allows a unit (e.g. - <filename>foo.service</filename>) to be enabled via - <command>systemctl enable</command>:</para> - - <programlisting>[Unit] -Description=Foo - -[Service] -ExecStart=/usr/sbin/foo-daemon - -<emphasis>[Install]</emphasis> -<emphasis>WantedBy=multi-user.target</emphasis></programlisting> - - <para>After running <command>systemctl enable</command>, a - symlink - <filename>/etc/systemd/system/multi-user.target.wants/foo.service</filename> - linking to the actual unit will be created. It tells systemd to - pull in the unit when starting - <filename>multi-user.target</filename>. The inverse - <command>systemctl disable</command> will remove that symlink - again.</para> - </example> - - <example> - <title>Overriding vendor settings</title> - - <para>There are two methods of overriding vendor settings in - unit files: copying the unit file from - <filename>/usr/lib/systemd/system</filename> to - <filename>/etc/systemd/system</filename> and modifying the - chosen settings. Alternatively, one can create a directory named - <filename><replaceable>unit</replaceable>.d/</filename> within - <filename>/etc/systemd/system</filename> and place a drop-in - file <filename><replaceable>name</replaceable>.conf</filename> - there that only changes the specific settings one is interested - in. Note that multiple such drop-in files are read if - present.</para> - - <para>The advantage of the first method is that one easily - overrides the complete unit, the vendor unit is not parsed at - all anymore. It has the disadvantage that improvements to the - unit file by the vendor are not automatically incorporated on - updates.</para> - - <para>The advantage of the second method is that one only - overrides the settings one specifically wants, where updates to - the unit by the vendor automatically apply. This has the - disadvantage that some future updates by the vendor might be - incompatible with the local changes.</para> - - <para>Note that for drop-in files, if one wants to remove - entries from a setting that is parsed as a list (and is not a - dependency), such as <varname>ConditionPathExists=</varname> (or - e.g. <varname>ExecStart=</varname> in service units), one needs - to first clear the list before re-adding all entries except the - one that is to be removed. See below for an example.</para> - - <para>This also applies for user instances of systemd, but with - different locations for the unit files. See the section on unit - load paths for further details.</para> - - <para>Suppose there is a vendor-supplied unit - <filename>/usr/lib/systemd/system/httpd.service</filename> with - the following contents:</para> - - <programlisting>[Unit] -Description=Some HTTP server -After=remote-fs.target sqldb.service -Requires=sqldb.service -AssertPathExists=/srv/webserver - -[Service] -Type=notify -ExecStart=/usr/sbin/some-fancy-httpd-server -Nice=5 - -[Install] -WantedBy=multi-user.target</programlisting> - - <para>Now one wants to change some settings as an administrator: - firstly, in the local setup, <filename>/srv/webserver</filename> - might not exist, because the HTTP server is configured to use - <filename>/srv/www</filename> instead. Secondly, the local - configuration makes the HTTP server also depend on a memory - cache service, <filename>memcached.service</filename>, that - should be pulled in (<varname>Requires=</varname>) and also be - ordered appropriately (<varname>After=</varname>). Thirdly, in - order to harden the service a bit more, the administrator would - like to set the <varname>PrivateTmp=</varname> setting (see - <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> - for details). And lastly, the administrator would like to reset - the niceness of the service to its default value of 0.</para> - - <para>The first possibility is to copy the unit file to - <filename>/etc/systemd/system/httpd.service</filename> and - change the chosen settings:</para> - - <programlisting>[Unit] -Description=Some HTTP server -After=remote-fs.target sqldb.service <emphasis>memcached.service</emphasis> -Requires=sqldb.service <emphasis>memcached.service</emphasis> -AssertPathExists=<emphasis>/srv/www</emphasis> - -[Service] -Type=notify -ExecStart=/usr/sbin/some-fancy-httpd-server -<emphasis>Nice=0</emphasis> -<emphasis>PrivateTmp=yes</emphasis> - -[Install] -WantedBy=multi-user.target</programlisting> - - <para>Alternatively, the administrator could create a drop-in - file - <filename>/etc/systemd/system/httpd.service.d/local.conf</filename> - with the following contents:</para> - - <programlisting>[Unit] -After=memcached.service -Requires=memcached.service -# Reset all assertions and then re-add the condition we want -AssertPathExists= -AssertPathExists=/srv/www - -[Service] -Nice=0 -PrivateTmp=yes</programlisting> - - <para>Note that dependencies (<varname>After=</varname>, etc.) - cannot be reset to an empty list, so dependencies can only be - added in drop-ins. If you want to remove dependencies, you have - to override the entire unit.</para> - - </example> - </refsect1> - - <refsect1> - <title>See Also</title> - <para> - <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>, - <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.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>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>, - <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>, - <citerefentry project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>1</manvolnum></citerefentry> - </para> - </refsect1> - -</refentry> |