systemd/man/systemd.scope.xml
2020-11-09 13:23:58 +09:00

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<?xml version='1.0'?>
<!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.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 [Scope]
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 [Scope] 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>