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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">
-
-<!--
- SPDX-License-Identifier: LGPL-2.1+
-
- This file is part of systemd.
-
- Copyright 2010 Lennart Poettering
--->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+ "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="systemd.target">
<refentryinfo>
<title>systemd.target</title>
<productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
</refentryinfo>
<refmeta>
<refsect1>
<title>Description</title>
- <para>A unit configuration file whose name ends in
- <literal>.target</literal> encodes information about a target unit
- of systemd, which is used for grouping units and as well-known
- synchronization points during start-up.</para>
+ <para>A unit configuration file whose name ends in <literal>.target</literal> encodes information about a
+ target unit of systemd. Target units are used to group units and to set synchronization points for
+ ordering dependencies with other unit files.</para>
<para>This unit type has no specific options. See
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for the common options of all unit configuration files. The common
- configuration items are configured in the generic [Unit] and
- [Install] sections. A separate [Target] section does not exist,
- since no target-specific options may be configured.</para>
-
- <para>Target units do not offer any additional functionality on
- top of the generic functionality provided by units. They exist
- merely to group units via dependencies (useful as boot targets),
- and to establish standardized names for synchronization points
- used in dependencies between units. Among other things, target
- units are a more flexible replacement for SysV runlevels in the
- classic SysV init system. (And for compatibility reasons special
- target units such as <filename>runlevel3.target</filename> exist
- which are used by the SysV runlevel compatibility code in systemd.
- See
- <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details).</para>
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for the
+ common options of all unit configuration files. The common configuration items are configured in the
+ generic [Unit] and [Install] sections. A separate [Target] section does not exist, since no
+ target-specific options may be configured.</para>
+
+ <para>Target units do not offer any additional functionality on top of the generic functionality provided
+ by units. They merely group units, allowing a single target name to be used in <varname>Wants=</varname>
+ and <varname>Requires=</varname> settings to establish a dependency on a set of units defined by the
+ target, and in <varname>Before=</varname> and <varname>After=</varname> settings to establish ordering.
+ Targets establish standardized names for synchronization points during boot and shutdown. Importantly,
+ see <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ for examples and descriptions of standard systemd targets.</para>
+
+ <para>Target units provide a more flexible replacement for SysV runlevels in the classic SysV init
+ system. For compatibility reasons special target units such as <filename>runlevel3.target</filename>
+ exist which are used by the SysV runlevel compatibility code in systemd, see
+ <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
+ details.</para>
+
+ <para>Note that a target unit file must not be empty, lest it be considered a masked unit. It is
+ recommended to provide a [Unit] section which includes informative <varname>Description=</varname> and
+ <varname>Documentation=</varname> options.</para>
</refsect1>
<refsect1>
- <title>Implicit Dependencies</title>
-
- <para>There are no implicit dependencies for target units.</para>
+ <title>Automatic Dependencies</title>
+
+ <refsect2>
+ <title>Implicit Dependencies</title>
+
+ <para>There are no implicit dependencies for target units.</para>
+ </refsect2>
+
+ <refsect2>
+ <title>Default Dependencies</title>
+
+ <para>The following dependencies are added unless
+ <varname>DefaultDependencies=no</varname> is set:</para>
+
+ <itemizedlist>
+ <listitem><para>Target units will automatically complement all configured dependencies of type
+ <varname>Wants=</varname> or <varname>Requires=</varname> with dependencies of type
+ <varname>After=</varname> unless <varname>DefaultDependencies=no</varname> is set in the specified
+ units.</para>
+
+ <para>Note that the reverse is not true. For example, defining <option>Wants=that.target</option> in
+ <filename index='false'>some.service</filename> will not automatically add the
+ <option>After=that.target</option> ordering dependency for <filename>some.service</filename>.
+ Instead, <filename>some.service</filename> should use the primary synchronization function of target
+ type units, by setting a specific <option>After=that.target</option> or
+ <option>Before=that.target</option> ordering dependency in its .service unit file.
+ </para></listitem>
+
+ <listitem><para>Target units automatically gain <varname>Conflicts=</varname>
+ and <varname>Before=</varname> dependencies against
+ <filename>shutdown.target</filename>.</para></listitem>
+ </itemizedlist>
+ </refsect2>
</refsect1>
<refsect1>
- <title>Default Dependencies</title>
-
- <para>The following dependencies are added unless
- <varname>DefaultDependencies=no</varname> is set:</para>
-
- <itemizedlist>
- <listitem><para>Target units will automatically complement all
- configured dependencies of type <varname>Wants=</varname> or
- <varname>Requires=</varname> with dependencies of type
- <varname>After=</varname> unless <varname>DefaultDependencies=no</varname>
- is set in the specified units. Note that <varname>Wants=</varname> or
- <varname>Requires=</varname> must be defined in the target unit itself — if
- you for example define <varname>Wants=</varname>some.target in
- some.service, the automatic ordering will not be added.</para></listitem>
-
- <listitem><para>Target units automatically gain <varname>Conflicts=</varname>
- dependency against <filename>shutdown.target</filename>.</para></listitem>
- </itemizedlist>
+ <title>Options</title>
+
+ <para>Target unit files may include [Unit] and [Install] sections, which are described in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ No options specific to this file type are supported.</para>
</refsect1>
<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.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- </para>
+ <para><simplelist type="inline">
+ <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
+ </simplelist></para>
</refsect1>
</refentry>
projects / thirdparty / systemd.git / blobdiff