Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/man/systemd.target.xml b/man/systemd.target.xml
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+<?xml version='1.0'?> <!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
+
+<refentry id="systemd.target">
+  <refentryinfo>
+    <title>systemd.target</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>systemd.target</refentrytitle>
+    <manvolnum>5</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>systemd.target</refname>
+    <refpurpose>Target unit configuration</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <para><filename><replaceable>target</replaceable>.target</filename></para>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <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 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>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>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>
+    <title>Example</title>
+
+    <example>
+      <title>Simple standalone target</title>
+
+      <programlisting># emergency-net.target
+
+[Unit]
+Description=Emergency Mode with Networking
+Requires=emergency.target systemd-networkd.service
+After=emergency.target systemd-networkd.service
+AllowIsolate=yes</programlisting>
+
+      <para>When adding dependencies to other units, it's important to check if they set
+      <varname>DefaultDependencies=</varname>. Service units, unless they set
+      <varname>DefaultDependencies=no</varname>, automatically get a dependency on
+      <filename>sysinit.target</filename>. In this case, both
+      <filename>emergency.target</filename> and <filename>systemd-networkd.service</filename>
+      have <varname>DefaultDependencies=no</varname>, so they are suitable for use
+      in this target, and do not pull in <filename>sysinit.target</filename>.</para>
+
+      <para>You can now switch into this emergency mode by running <varname>systemctl
+      isolate emergency-net.target</varname> or by passing the option
+      <varname>systemd.unit=emergency-net.target</varname> on the kernel command
+      line.</para>
+
+      <para>Other units can have <varname>WantedBy=emergency-net.target</varname> in the
+      <varname>[Install]</varname> section. After they are enabled using
+      <command>systemctl enable</command>, they will be started before
+      <varname>emergency-net.target</varname> is started. It is also possible to add
+      arbitrary units as dependencies of <filename>emergency.target</filename> without
+      modifying them by using <command>systemctl add-wants</command>.
+      </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.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>
+  </refsect1>
+
+</refentry>