systemd/man/systemd.scope.xml

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<refentry id="systemd.scope">
  <refentryinfo>
    <title>systemd.scope</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd.scope</refentrytitle>
    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd.scope</refname>
    <refpurpose>Scope unit configuration</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename><replaceable>scope</replaceable>.scope</filename></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>Scope units are not configured via unit configuration files,
    but are only created programmatically using the bus interfaces of
    systemd. They are named similar to filenames. A unit whose name
    ends in <literal>.scope</literal> refers to a scope unit. Scopes
    units manage a set of system processes. Unlike service units, scope
    units manage externally created processes, and do not fork off
    processes on its own.</para>

    <para>The main purpose of scope units is grouping worker processes
    of a system service for organization and for managing resources.</para>

    <para><command>systemd-run <option>--scope</option></command> may
    be used to easily launch a command in a new scope unit from the
    command line.</para>

    <para>See the <ulink
    url="https://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
    Control Group Interfaces</ulink> for an introduction on how to make
    use of scope units from programs.</para>

    <para>Note that, unlike service units, scope units have no "main" process: all processes in the scope are
    equivalent. The lifecycle of the scope unit is thus not bound to the lifetime of one specific process,
    but to the existence of at least one process in the scope. This also means that the exit statuses of
    these processes are not relevant for the scope unit failure state. Scope units may still enter a failure
    state, for example due to resource exhaustion or stop timeouts being reached, but not due to programs
    inside of them terminating uncleanly. Since processes managed as scope units generally remain children of
    the original process that forked them off, it is also the job of that process to collect their exit
    statuses and act on them as needed.</para>
  </refsect1>

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

    <refsect2>
      <title>Implicit Dependencies</title>

      <para>Implicit dependencies may be added as result of
      resource control parameters as documented in
      <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
    </refsect2>

    <refsect2>
      <title>Default Dependencies</title>

      <para>The following dependencies are added unless
      <varname>DefaultDependencies=no</varname> is set:</para>

      <itemizedlist>
        <listitem><para>Scope units will automatically have dependencies of
        type <varname>Conflicts=</varname> and
        <varname>Before=</varname> on
        <filename>shutdown.target</filename>. These ensure
        that scope units are removed prior to system
        shutdown. Only scope units involved with early boot or
        late system shutdown should disable
        <varname>DefaultDependencies=</varname> option.</para></listitem>
      </itemizedlist>
    </refsect2>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>Scope files may include a <literal>[Scope]</literal>
    section, which carries information about the scope and the
    units it contains. A number of options that may be used in
    this section are shared with other unit types. These options are
    documented in
    <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
    and
    <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
    The options specific to the <literal>[Scope]</literal> section
    of scope units are the following:</para>

    <variablelist class='unit-directives'>
      <varlistentry>
        <term><varname>RuntimeMaxSec=</varname></term>

        <listitem><para>Configures a maximum time for the scope to run. If this is used and the scope has been
        active for longer than the specified time it is terminated and put into a failure state. Pass
        <literal>infinity</literal> (the default) to configure no runtime limit.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
    </para>
  </refsect1>

</refentry>