Merge pull request #6200 from poettering/ioprio-transient

[thirdparty/systemd.git] / man / systemd.target.xml

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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">

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<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>
    <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, which is used for grouping units and as well-known
    synchronization points during start-up.</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>
  </refsect1>

  <refsect1>
    <title>Automatic Dependencies</title>

    <para>Unless <varname>DefaultDependencies=</varname> is set to
    <option>no</option> in either of related units or an explicit ordering
    dependency is already defined, target units will implicitly complement all
    configured dependencies of type <varname>Wants=</varname> or
    <varname>Requires=</varname> with dependencies of type
    <varname>After=</varname>. 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 implicit ordering will not be added.</para>

    <para>All target units automatically gain <varname>Conflicts=</varname>
    dependency against shutdown.target unless <varname>DefaultDependencies=</varname>
    is set to <option>no</option>.</para>

  </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>