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1229 lines
72 KiB
XML
1229 lines
72 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
|
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="systemd.service">
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<refentryinfo>
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<title>systemd.service</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>systemd.service</refentrytitle>
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<manvolnum>5</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>systemd.service</refname>
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<refpurpose>Service unit configuration</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para><filename><replaceable>service</replaceable>.service</filename></para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>A unit configuration file whose name ends in
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<filename>.service</filename> encodes information
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about a process controlled and supervised by
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systemd.</para>
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<para>This man page lists the configuration options
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specific to this unit type. See
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<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for the common options of all unit configuration
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files. The common configuration items are configured
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in the generic <literal>[Unit]</literal> and
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<literal>[Install]</literal> sections. The service
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specific configuration options are configured in the
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<literal>[Service]</literal> section.</para>
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<para>Additional options are listed in
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<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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which define the execution environment the commands
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are executed in, and in
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<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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which define the way the processes of the service are
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terminated, and in
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<citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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which configure resource control settings for the
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processes of the service.</para>
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<para>Unless <varname>DefaultDependencies=</varname>
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is set to <option>false</option>, service units will
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implicitly have dependencies of type
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<varname>Requires=</varname> and
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<varname>After=</varname> on
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<filename>basic.target</filename> as well as
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dependencies of type <varname>Conflicts=</varname> and
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<varname>Before=</varname> on
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<filename>shutdown.target</filename>. These ensure
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that normal service units pull in basic system
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initialization, and are terminated cleanly prior to
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system shutdown. Only services involved with early
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boot or late system shutdown should disable this
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option.</para>
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<para>If a service is requested under a certain name
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but no unit configuration file is found, systemd looks
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for a SysV init script by the same name (with the
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<filename>.service</filename> suffix removed) and
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dynamically creates a service unit from that
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script. This is useful for compatibility with
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SysV. Note that this compatibility is quite
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comprehensive but not 100%. For details about the
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incompatibilities, see the <ulink
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url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
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with SysV</ulink> document.
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</para>
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</refsect1>
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<refsect1>
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<title>Options</title>
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<para>Service files must include a
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<literal>[Service]</literal> section, which carries
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information about the service and the process it
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supervises. A number of options that may be used in
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this section are shared with other unit types. These
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options are documented in
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<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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and
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<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
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options specific to the <literal>[Service]</literal>
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section of service units are the following:</para>
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<variablelist class='unit-directives'>
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<varlistentry>
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<term><varname>Type=</varname></term>
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<listitem><para>Configures the process
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start-up type for this service
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unit. One of <option>simple</option>,
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<option>forking</option>,
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<option>oneshot</option>,
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<option>dbus</option>,
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<option>notify</option> or
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<option>idle</option>.</para>
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<para>If set to
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<option>simple</option> (the default
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value if neither
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<varname>Type=</varname> nor
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<varname>BusName=</varname> are
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specified), it is expected that the
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process configured with
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<varname>ExecStart=</varname> is the
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main process of the service. In this
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mode, if the process offers
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functionality to other processes on
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the system, its communication channels
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should be installed before the daemon
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is started up (e.g. sockets set up by
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systemd, via socket activation), as
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systemd will immediately proceed
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starting follow-up units.</para>
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<para>If set to
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<option>forking</option>, it is
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expected that the process configured
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with <varname>ExecStart=</varname>
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will call <function>fork()</function>
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as part of its start-up. The parent process is
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expected to exit when start-up is
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complete and all communication
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channels are set up. The child continues
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to run as the main daemon
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process. This is the behavior of
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traditional UNIX daemons. If this
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setting is used, it is recommended to
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also use the
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<varname>PIDFile=</varname> option, so
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that systemd can identify the main
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process of the daemon. systemd will
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proceed with starting follow-up units
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as soon as the parent process
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exits.</para>
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<para>Behavior of
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<option>oneshot</option> is similar
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to <option>simple</option>; however,
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it is expected that the process has to
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exit before systemd starts follow-up
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units. <varname>RemainAfterExit=</varname>
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is particularly useful for this type
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of service.</para>
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<para>Behavior of
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<option>dbus</option> is similar to
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<option>simple</option>; however, it is
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expected that the daemon acquires a
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name on the D-Bus bus, as configured
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by
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<varname>BusName=</varname>. systemd
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will proceed with starting follow-up
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units after the D-Bus bus name has been
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acquired. Service units with this
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option configured implicitly gain
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dependencies on the
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<filename>dbus.socket</filename>
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unit. This type is the default if
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<varname>BusName=</varname> is
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specified.</para>
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<para>Behavior of
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<option>notify</option> is similar to
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<option>simple</option>; however, it is
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expected that the daemon sends a
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notification message via
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<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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or an equivalent call when it has finished
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starting up. systemd will proceed with
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starting follow-up units after this
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notification message has been sent. If
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this option is used,
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<varname>NotifyAccess=</varname> (see
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below) should be set to open access to
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the notification socket provided by
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systemd. If
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<varname>NotifyAccess=</varname> is
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not set, it will be implicitly set to
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<option>main</option>. Note that
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currently
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<varname>Type=</varname><option>notify</option>
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will not work if used in combination with
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<varname>PrivateNetwork=</varname><option>yes</option>.</para>
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<para>Behavior of
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<option>idle</option> is very similar
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to <option>simple</option>; however,
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actual execution of the service
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binary is delayed until all jobs are
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dispatched. This may be used to avoid
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interleaving of output of shell
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services with the status output on the
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console.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>RemainAfterExit=</varname></term>
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<listitem><para>Takes a boolean value
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that specifies whether the service
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shall be considered active even when
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all its processes exited. Defaults to
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<option>no</option>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>GuessMainPID=</varname></term>
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<listitem><para>Takes a boolean value
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that specifies whether systemd should
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|
try to guess the main PID of a service
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|
if it cannot be determined
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reliably. This option is ignored
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|
unless <option>Type=forking</option>
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|
is set and <option>PIDFile=</option>
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|
is unset because for the other types
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|
or with an explicitly configured PID
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|
file, the main PID is always known. The
|
|
guessing algorithm might come to
|
|
incorrect conclusions if a daemon
|
|
consists of more than one process. If
|
|
the main PID cannot be determined,
|
|
failure detection and automatic
|
|
restarting of a service will not work
|
|
reliably. Defaults to
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<option>yes</option>.</para>
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|
</listitem>
|
|
</varlistentry>
|
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|
<varlistentry>
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<term><varname>PIDFile=</varname></term>
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<listitem><para>Takes an absolute file
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name pointing to the PID file of this
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daemon. Use of this option is
|
|
recommended for services where
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|
<varname>Type=</varname> is set to
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<option>forking</option>. systemd will
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|
read the PID of the main process of
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|
the daemon after start-up of the
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service. systemd will not write to the
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file configured here.</para>
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|
</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>BusName=</varname></term>
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<listitem><para>Takes a D-Bus bus
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|
name that this service is reachable
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as. This option is mandatory for
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|
services where
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|
<varname>Type=</varname> is set to
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|
<option>dbus</option>, but its use
|
|
is otherwise recommended if the process
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|
takes a name on the D-Bus bus.</para>
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</listitem>
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</varlistentry>
|
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|
<varlistentry>
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<term><varname>ExecStart=</varname></term>
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<listitem><para>Commands with their
|
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arguments that are executed when this
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service is started. For each of the
|
|
specified commands, the first argument
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|
must be an absolute and literal path
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|
to an executable.</para>
|
|
|
|
<para>When <varname>Type</varname> is
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|
not <option>oneshot</option>, only one
|
|
command may be given. When
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<varname>Type=oneshot</varname> is
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|
used, more than one command may be
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specified. Multiple command lines may
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|
be concatenated in a single directive
|
|
by separating them with semicolons
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(these semicolons must be passed as
|
|
separate words). Alternatively, this
|
|
directive may be specified more than
|
|
once with the same effect.
|
|
Lone semicolons may be escaped as
|
|
<literal>\;</literal>. If the empty
|
|
string is assigned to this option, the
|
|
list of commands to start is reset,
|
|
prior assignments of this option will
|
|
have no effect.</para>
|
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<para>Each command line is split on
|
|
whitespace, with the first item being
|
|
the command to execute, and the
|
|
subsequent items being the arguments.
|
|
Double quotes ("...") and single
|
|
quotes ('...') may be used, in which
|
|
case everything until the next
|
|
matching quote becomes part of the
|
|
same argument. Quotes themselves are
|
|
removed after parsing. In addition, a
|
|
trailing backslash
|
|
(<literal>\</literal>) may be used to
|
|
merge lines. This syntax is intended
|
|
to be very similar to shell syntax,
|
|
but only the meta-characters and
|
|
expansions described in the following
|
|
paragraphs are understood.
|
|
Specifically, redirection using
|
|
<literal><</literal>,
|
|
<literal><<</literal>,
|
|
<literal>></literal>, and
|
|
<literal>>></literal>, pipes
|
|
using <literal>|</literal>, and
|
|
running programs in the background
|
|
using <literal>&</literal>
|
|
and <emphasis>other elements of shell
|
|
syntax are not supported</emphasis>.
|
|
</para>
|
|
|
|
<para>If more than one command is
|
|
specified, the commands are invoked
|
|
sequentially in the order they appear
|
|
in the unit file. If one of the
|
|
commands fails (and is not prefixed
|
|
with <literal>-</literal>), other lines
|
|
are not executed, and the unit is
|
|
considered failed.</para>
|
|
|
|
<para>Unless
|
|
<varname>Type=forking</varname> is
|
|
set, the process started via this
|
|
command line will be considered the
|
|
main process of the daemon.</para>
|
|
|
|
<para>The command line accepts
|
|
<literal>%</literal> specifiers as
|
|
described in
|
|
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
|
|
Note that the first argument of the
|
|
command line (i.e. the program to
|
|
execute) may not include
|
|
specifiers.</para>
|
|
|
|
<para>Basic environment variable
|
|
substitution is supported. Use
|
|
<literal>${FOO}</literal> as part of a
|
|
word, or as a word of its own, on the
|
|
command line, in which case it will be
|
|
replaced by the value of the
|
|
environment variable including all
|
|
whitespace it contains, resulting in a
|
|
single argument. Use
|
|
<literal>$FOO</literal> as a separate
|
|
word on the command line, in which
|
|
case it will be replaced by the value
|
|
of the environment variable split at
|
|
whitespace, resulting in zero or more
|
|
arguments. To pass a literal dollar
|
|
sign, use <literal>$$</literal>.
|
|
Variables whose value is not known at
|
|
expansion time are treated as empty
|
|
strings. Note that the first argument
|
|
(i.e. the program to execute) may not
|
|
be a variable.</para>
|
|
|
|
<para>Variables to be used in this
|
|
fashion may be defined through
|
|
<varname>Environment=</varname> and
|
|
<varname>EnvironmentFile=</varname>.
|
|
In addition, variables listed in the
|
|
section "Environment variables in
|
|
spawned processes" in
|
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
which are considered "static
|
|
configuration", may be used (this includes
|
|
e.g. <varname>$USER</varname>, but not
|
|
<varname>$TERM</varname>).</para>
|
|
|
|
<para>Optionally, if the absolute file
|
|
name is prefixed with
|
|
<literal>@</literal>, the second token
|
|
will be passed as
|
|
<literal>argv[0]</literal> to the
|
|
executed process, followed by the
|
|
further arguments specified. If the
|
|
absolute filename is prefixed with
|
|
<literal>-</literal>, an exit code of
|
|
the command normally considered a
|
|
failure (i.e. non-zero exit status or
|
|
abnormal exit due to signal) is ignored
|
|
and considered success. If both
|
|
<literal>-</literal> and
|
|
<literal>@</literal> are used, they
|
|
can appear in either order.</para>
|
|
|
|
<para>Note that this setting does not
|
|
directly support shell command
|
|
lines. If shell command lines are to
|
|
be used, they need to be passed
|
|
explicitly to a shell implementation
|
|
of some kind. Example:</para>
|
|
<programlisting>ExecStart=/bin/sh -c 'dmesg | tac'</programlisting>
|
|
<para>Example:</para>
|
|
<programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"</programlisting>
|
|
<para>This will execute
|
|
<command>/bin/echo</command> two
|
|
times, each time with one argument:
|
|
<literal>one</literal> and
|
|
<literal>two two</literal>,
|
|
respectively. Because two commands are
|
|
specified,
|
|
<varname>Type=oneshot</varname> must
|
|
be used.</para>
|
|
|
|
<para>Example:</para>
|
|
<programlisting>ExecStart=/bin/echo / >/dev/null & \; \
|
|
/bin/ls</programlisting>
|
|
<para>This will execute
|
|
<command>/bin/echo</command> with five
|
|
arguments: <literal>/</literal>,
|
|
<literal>>/dev/null</literal>,
|
|
<literal>&</literal>,
|
|
<literal>;</literal>, and
|
|
<literal>/bin/ls</literal>.</para>
|
|
|
|
<para>Example:</para>
|
|
<programlisting>Environment="ONE=one" 'TWO=two two'
|
|
ExecStart=/bin/echo $ONE $TWO ${TWO}</programlisting>
|
|
<para>This will execute
|
|
<command>/bin/echo</command> with four
|
|
arguments: <literal>one</literal>,
|
|
<literal>two</literal>,
|
|
<literal>two</literal>, and
|
|
<literal>two two</literal>.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ExecStartPre=</varname></term>
|
|
<term><varname>ExecStartPost=</varname></term>
|
|
<listitem><para>Additional commands
|
|
that are executed before or after
|
|
the command in
|
|
<varname>ExecStart=</varname>, respectively.
|
|
Syntax is the same as for
|
|
<varname>ExecStart=</varname>, except
|
|
that multiple command lines are allowed
|
|
and the commands are executed one
|
|
after the other, serially.</para>
|
|
|
|
<para>If any of those commands (not
|
|
prefixed with <literal>-</literal>)
|
|
fail, the rest are not executed and
|
|
the unit is considered failed.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ExecReload=</varname></term>
|
|
<listitem><para>Commands to execute to
|
|
trigger a configuration reload in the
|
|
service. This argument takes multiple
|
|
command lines, following the same
|
|
scheme as described for
|
|
<varname>ExecStart=</varname>
|
|
above. Use of this setting is
|
|
optional. Specifier and environment
|
|
variable substitution is supported
|
|
here following the same scheme as for
|
|
<varname>ExecStart=</varname>.</para>
|
|
|
|
<para>One additional, special
|
|
environment variable is set: if known,
|
|
<varname>$MAINPID</varname> is set to
|
|
the main process of the daemon, and
|
|
may be used for command lines like the
|
|
following:</para>
|
|
|
|
<programlisting>/bin/kill -HUP $MAINPID</programlisting>
|
|
|
|
<para>Note however that reloading a
|
|
daemon by sending a signal (as with
|
|
the example line above) is usually not
|
|
a good choice, because this is an
|
|
asynchronous operation and hence not
|
|
suitable to order reloads of multiple
|
|
services against each other. It is
|
|
strongly recommended to set
|
|
<varname>ExecReload=</varname> to a
|
|
command that not only triggers a
|
|
configuration reload of the daemon,
|
|
but also synchronously waits for it to
|
|
complete.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ExecStop=</varname></term>
|
|
<listitem><para>Commands to execute to
|
|
stop the service started via
|
|
<varname>ExecStart=</varname>. This
|
|
argument takes multiple command lines,
|
|
following the same scheme as described
|
|
for <varname>ExecStart=</varname>
|
|
above. Use of this setting is
|
|
optional. After the commands configured
|
|
in this option are run, all processes
|
|
remaining for a service are
|
|
terminated according to the
|
|
<varname>KillMode=</varname> setting
|
|
(see
|
|
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
|
|
this option is not specified, the
|
|
process is terminated immediately when
|
|
service stop is requested. Specifier
|
|
and environment variable substitution
|
|
is supported (including
|
|
<varname>$MAINPID</varname>, see
|
|
above).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ExecStopPost=</varname></term>
|
|
<listitem><para>Additional commands
|
|
that are executed after the service
|
|
was stopped. This includes cases where
|
|
the commands configured in
|
|
<varname>ExecStop=</varname> were used,
|
|
where the service does not have any
|
|
<varname>ExecStop=</varname> defined, or
|
|
where the service exited unexpectedly. This
|
|
argument takes multiple command lines,
|
|
following the same scheme as described
|
|
for <varname>ExecStart</varname>. Use
|
|
of these settings is
|
|
optional. Specifier and environment
|
|
variable substitution is
|
|
supported.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>RestartSec=</varname></term>
|
|
<listitem><para>Configures the time to
|
|
sleep before restarting a service (as
|
|
configured with
|
|
<varname>Restart=</varname>). Takes a
|
|
unit-less value in seconds, or a time
|
|
span value such as "5min
|
|
20s". Defaults to
|
|
100ms.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>TimeoutStartSec=</varname></term>
|
|
<listitem><para>Configures the time to
|
|
wait for start-up. If a
|
|
daemon service does not signal
|
|
start-up completion within the
|
|
configured time, the service will be
|
|
considered failed and will be shut
|
|
down again.
|
|
Takes a unit-less value in seconds, or a
|
|
time span value such as "5min
|
|
20s". Pass <literal>0</literal> to
|
|
disable the timeout logic. Defaults to
|
|
<varname>DefaultTimeoutStartSec=</varname> from
|
|
the manager configuration file, except
|
|
when <varname>Type=oneshot</varname> is
|
|
used, in which case the timeout
|
|
is disabled by default
|
|
(see <citerefentry><refentrytitle>systemd-systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>TimeoutStopSec=</varname></term>
|
|
<listitem><para>Configures the time to
|
|
wait for stop. If a service is asked
|
|
to stop, but does not terminate in the
|
|
specified time, it will be terminated
|
|
forcibly via <constant>SIGTERM</constant>,
|
|
and after another timeout of equal duration
|
|
with <constant>SIGKILL</constant> (see
|
|
<varname>KillMode=</varname>
|
|
in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
|
|
Takes a unit-less value in seconds, or a
|
|
time span value such as "5min
|
|
20s". Pass <literal>0</literal> to disable
|
|
the timeout logic. Defaults to
|
|
<varname>DefaultTimeoutStopSec=</varname> from the
|
|
manager configuration file
|
|
(see <citerefentry><refentrytitle>systemd-systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>TimeoutSec=</varname></term>
|
|
<listitem><para>A shorthand for configuring
|
|
both <varname>TimeoutStartSec=</varname>
|
|
and <varname>TimeoutStopSec=</varname>
|
|
to the specified value.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>WatchdogSec=</varname></term>
|
|
<listitem><para>Configures the
|
|
watchdog timeout for a service. The
|
|
watchdog is activated when the start-up is
|
|
completed. The service must call
|
|
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
regularly with <literal>WATCHDOG=1</literal>
|
|
(i.e. the "keep-alive ping"). If the time
|
|
between two such calls is larger than
|
|
the configured time, then the service
|
|
is placed in a failed state. By
|
|
setting <varname>Restart=</varname> to
|
|
<option>on-failure</option> or
|
|
<option>always</option>, the service
|
|
will be automatically restarted. The
|
|
time configured here will be passed to
|
|
the executed service process in the
|
|
<varname>WATCHDOG_USEC=</varname>
|
|
environment variable. This allows
|
|
daemons to automatically enable the
|
|
keep-alive pinging logic if watchdog
|
|
support is enabled for the service. If
|
|
this option is used,
|
|
<varname>NotifyAccess=</varname> (see
|
|
below) should be set to open access to
|
|
the notification socket provided by
|
|
systemd. If
|
|
<varname>NotifyAccess=</varname> is
|
|
not set, it will be implicitly set to
|
|
<option>main</option>. Defaults to 0,
|
|
which disables this
|
|
feature.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Restart=</varname></term>
|
|
<listitem><para>Configures whether the
|
|
service shall be restarted when the
|
|
service process exits, is killed,
|
|
or a timeout is reached. The service
|
|
process may be the main service
|
|
process, but it may also be one of the
|
|
processes specified with
|
|
<varname>ExecStartPre=</varname>,
|
|
<varname>ExecStartPost=</varname>,
|
|
<varname>ExecStop=</varname>,
|
|
<varname>ExecStopPost=</varname>, or
|
|
<varname>ExecReload=</varname>.
|
|
When the death of the process is a
|
|
result of systemd operation (e.g. service
|
|
stop or restart), the service will not be
|
|
restarted. Timeouts include missing
|
|
the watchdog "keep-alive ping"
|
|
deadline and a service start, reload,
|
|
and stop operation timeouts.</para>
|
|
|
|
<para>Takes one of
|
|
<option>no</option>,
|
|
<option>on-success</option>,
|
|
<option>on-failure</option>,
|
|
<option>on-abnormal</option>,
|
|
<option>on-watchdog</option>,
|
|
<option>on-abort</option>, or
|
|
<option>always</option>. If set to
|
|
<option>no</option> (the default), the
|
|
service will not be restarted. If set
|
|
to <option>on-success</option>, it
|
|
will be restarted only when the
|
|
service process exits cleanly. In
|
|
this context, a clean exit means an
|
|
exit code of 0, or one of the signals
|
|
<constant>SIGHUP</constant>,
|
|
<constant>SIGINT</constant>,
|
|
<constant>SIGTERM</constant> or
|
|
<constant>SIGPIPE</constant>, and
|
|
additionally, exit statuses and
|
|
signals specified in
|
|
<varname>SuccessExitStatus=</varname>.
|
|
If set to <option>on-failure</option>,
|
|
the service will be restarted when the
|
|
process exits with a non-zero exit
|
|
code, is terminated by a signal
|
|
(including on core dump, but excluding
|
|
the aforementiond four signals), when
|
|
an operation (such as service reload)
|
|
times out, and when the configured
|
|
watchdog timeout is triggered. If set
|
|
to <option>on-abnormal</option>, the
|
|
service will be restarted when the
|
|
process is terminated by a signal
|
|
(including on core dump, excluding the
|
|
aforementioned four signals), when an
|
|
operation times out, or when the
|
|
watchdog timeout is triggered. If set
|
|
to <option>on-abort</option>, the
|
|
service will be restarted only if the
|
|
service process exits due to an
|
|
uncaught signal not specified as a
|
|
clean exit status. If set to
|
|
<option>on-watchdog</option>, the
|
|
service will be restarted only if the
|
|
watchdog timeout for the service
|
|
expires. If set to
|
|
<option>always</option>, the service
|
|
will be restarted regardless of
|
|
whether it exited cleanly or not, got
|
|
terminated abnormally by a signal, or
|
|
hit a timeout.</para>
|
|
|
|
<table>
|
|
<title>Exit causes and the effect of the <varname>Restart=</varname> settings on them</title>
|
|
|
|
<tgroup cols='2'>
|
|
<colspec colname='path' />
|
|
<colspec colname='expl' />
|
|
<thead>
|
|
<row>
|
|
<entry>Restart settings/Exit causes</entry>
|
|
<entry><option>no</option></entry>
|
|
<entry><option>always</option></entry>
|
|
<entry><option>on-success</option></entry>
|
|
<entry><option>on-failure</option></entry>
|
|
<entry><option>on-abnormal</option></entry>
|
|
<entry><option>on-abort</option></entry>
|
|
<entry><option>on-watchdog</option></entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>Clean exit code or signal</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry/>
|
|
<entry/>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>Unclean exit code</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry/>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>Unclean signal</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry>X</entry>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>Timeout</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry/>
|
|
</row>
|
|
<row>
|
|
<entry>Watchdog</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
<entry>X</entry>
|
|
<entry/>
|
|
<entry>X</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
|
|
<para>As exceptions to the setting
|
|
above the service will not be
|
|
restarted if the exit code or signal
|
|
is specified in
|
|
<varname>RestartPreventExitStatus=</varname>
|
|
(see below). Also, the services will
|
|
always be restarted if the exit code
|
|
or signal is specified in
|
|
<varname>RestartForceExitStatus=</varname>
|
|
(see below).</para>
|
|
|
|
<para>Setting this to
|
|
<option>on-failure</option> is the
|
|
recommended choice for long-running
|
|
services, in order to increase
|
|
reliability by attempting automatic
|
|
recovery from errors. For services
|
|
that shall be able to terminate on
|
|
their own choice (and avoid
|
|
immediate restarting),
|
|
<option>on-abnormal</option> is an
|
|
alternative choice.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>SuccessExitStatus=</varname></term>
|
|
<listitem><para>Takes a list of exit
|
|
status definitions that when returned
|
|
by the main service process will be
|
|
considered successful termination, in
|
|
addition to the normal successful exit
|
|
code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
|
|
<constant>SIGTERM</constant>, and <constant>SIGPIPE</constant>. Exit status
|
|
definitions can either be numeric exit
|
|
codes or termination signal names,
|
|
separated by spaces. For example:
|
|
<programlisting>SuccessExitStatus=1 2 8 SIGKILL</programlisting>
|
|
ensures that exit codes 1, 2, 8 and
|
|
the termination signal
|
|
<constant>SIGKILL</constant> are
|
|
considered clean service terminations.
|
|
</para>
|
|
|
|
<para>Note that if a process has a
|
|
signal handler installed and exits by
|
|
calling
|
|
<citerefentry><refentrytitle>_exit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
in response to a signal, the
|
|
information about the signal is lost.
|
|
Programs should instead perform cleanup and kill themselves with the same signal instead. See
|
|
<ulink url="http://www.cons.org/cracauer/sigint.html">Proper handling of SIGINT/SIGQUIT — How to be a proper program</ulink>.</para>
|
|
|
|
<para>This option may appear more than once,
|
|
in which case the list of successful
|
|
exit statuses is merged. If the empty
|
|
string is assigned to this option, the
|
|
list is reset, all prior assignments
|
|
of this option will have no
|
|
effect.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>RestartPreventExitStatus=</varname></term>
|
|
<listitem><para>Takes a list of exit
|
|
status definitions that when returned
|
|
by the main service process will
|
|
prevent automatic service restarts,
|
|
regardless of the restart setting
|
|
configured with
|
|
<varname>Restart=</varname>. Exit
|
|
status definitions can either be
|
|
numeric exit codes or termination
|
|
signal names, and are separated by
|
|
spaces. Defaults to the empty list, so
|
|
that, by default, no exit status is
|
|
excluded from the configured restart
|
|
logic. For example:
|
|
<programlisting>RestartPreventExitStatus=1 6 SIGABRT</programlisting> ensures that exit
|
|
codes 1 and 6 and the termination
|
|
signal <constant>SIGABRT</constant> will
|
|
not result in automatic service
|
|
restarting. This
|
|
option may appear more than once, in
|
|
which case the list of restart-preventing
|
|
statuses is merged. If the empty
|
|
string is assigned to this option, the
|
|
list is reset and all prior assignments
|
|
of this option will have no
|
|
effect.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>RestartForceExitStatus=</varname></term>
|
|
<listitem><para>Takes a list of exit
|
|
status definitions that when returned
|
|
by the main service process will force
|
|
automatic service restarts, regardless
|
|
of the restart setting configured with
|
|
<varname>Restart=</varname>. The
|
|
argument format is similar to
|
|
<varname>RestartPreventExitStatus=</varname>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>PermissionsStartOnly=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
argument. If true, the permission-related
|
|
execution options, as
|
|
configured with
|
|
<varname>User=</varname> and similar
|
|
options (see
|
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
for more information), are only applied
|
|
to the process started with
|
|
<varname>ExecStart=</varname>, and not
|
|
to the various other
|
|
<varname>ExecStartPre=</varname>,
|
|
<varname>ExecStartPost=</varname>,
|
|
<varname>ExecReload=</varname>,
|
|
<varname>ExecStop=</varname>, and
|
|
<varname>ExecStopPost=</varname>
|
|
commands. If false, the setting is
|
|
applied to all configured commands the
|
|
same way. Defaults to
|
|
false.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>RootDirectoryStartOnly=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
argument. If true, the root directory,
|
|
as configured with the
|
|
<varname>RootDirectory=</varname>
|
|
option (see
|
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
for more information), is only applied
|
|
to the process started with
|
|
<varname>ExecStart=</varname>, and not
|
|
to the various other
|
|
<varname>ExecStartPre=</varname>,
|
|
<varname>ExecStartPost=</varname>,
|
|
<varname>ExecReload=</varname>,
|
|
<varname>ExecStop=</varname>, and
|
|
<varname>ExecStopPost=</varname>
|
|
commands. If false, the setting is
|
|
applied to all configured commands the
|
|
same way. Defaults to
|
|
false.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>NonBlocking=</varname></term>
|
|
<listitem><para>Set the
|
|
<constant>O_NONBLOCK</constant> flag
|
|
for all file descriptors passed via
|
|
socket-based activation. If true, all
|
|
file descriptors >= 3 (i.e. all except
|
|
stdin, stdout, and stderr) will have
|
|
the <constant>O_NONBLOCK</constant> flag
|
|
set and hence are in
|
|
non-blocking mode. This option is only
|
|
useful in conjunction with a socket
|
|
unit, as described in
|
|
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
|
|
to false.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>NotifyAccess=</varname></term>
|
|
<listitem><para>Controls access to the
|
|
service status notification socket, as
|
|
accessible via the
|
|
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
call. Takes one of
|
|
<option>none</option> (the default),
|
|
<option>main</option> or
|
|
<option>all</option>. If
|
|
<option>none</option>, no daemon status
|
|
updates are accepted from the service
|
|
processes, all status update messages
|
|
are ignored. If <option>main</option>,
|
|
only service updates sent from the
|
|
main process of the service are
|
|
accepted. If <option>all</option>, all
|
|
services updates from all members of
|
|
the service's control group are
|
|
accepted. This option should be set to
|
|
open access to the notification socket
|
|
when using
|
|
<varname>Type=notify</varname> or
|
|
<varname>WatchdogSec=</varname> (see
|
|
above). If those options are used but
|
|
<varname>NotifyAccess=</varname> is not
|
|
configured, it will be implicitly set
|
|
to
|
|
<option>main</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Sockets=</varname></term>
|
|
<listitem><para>Specifies the name of
|
|
the socket units this service shall
|
|
inherit the sockets from when the
|
|
service is started. Normally it
|
|
should not be necessary to use this
|
|
setting as all sockets whose unit
|
|
shares the same name as the service
|
|
(ignoring the different suffix of course)
|
|
are passed to the spawned
|
|
process.</para>
|
|
|
|
<para>Note that the same socket may be
|
|
passed to multiple processes at the
|
|
same time. Also note that a different
|
|
service may be activated on incoming
|
|
traffic than that which inherits the
|
|
sockets. Or in other words: the
|
|
<varname>Service=</varname> setting of
|
|
<filename>.socket</filename> units
|
|
does not have to match the inverse of
|
|
the <varname>Sockets=</varname>
|
|
setting of the
|
|
<filename>.service</filename> it
|
|
refers to.</para>
|
|
|
|
<para>This option may appear more than
|
|
once, in which case the list of socket
|
|
units is merged. If the empty string
|
|
is assigned to this option, the list of
|
|
sockets is reset, and all prior uses of
|
|
this setting will have no
|
|
effect.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>StartLimitInterval=</varname></term>
|
|
<term><varname>StartLimitBurst=</varname></term>
|
|
|
|
<listitem><para>Configure service
|
|
start rate limiting. By default,
|
|
services which are started more
|
|
than 5 times within 10 seconds are not
|
|
permitted to start any more times
|
|
until the 10 second interval ends. With
|
|
these two options, this rate limiting
|
|
may be modified. Use
|
|
<varname>StartLimitInterval=</varname>
|
|
to configure the checking interval (defaults to
|
|
<varname>DefaultStartLimitInterval=</varname> in
|
|
manager configuration file, set to 0 to disable
|
|
any kind of rate limiting). Use
|
|
<varname>StartLimitBurst=</varname> to
|
|
configure how many starts per interval
|
|
are allowed (defaults to
|
|
<varname>DefaultStartLimitBurst=</varname> in
|
|
manager configuration file). These
|
|
configuration options are particularly
|
|
useful in conjunction with
|
|
<varname>Restart=</varname>; however,
|
|
they apply to all kinds of starts
|
|
(including manual), not just those
|
|
triggered by the
|
|
<varname>Restart=</varname> logic.
|
|
Note that units which are configured
|
|
for <varname>Restart=</varname> and
|
|
which reach the start limit are not
|
|
attempted to be restarted anymore;
|
|
however, they may still be restarted
|
|
manually at a later point, from which
|
|
point on, the restart logic is again
|
|
activated. Note that
|
|
<command>systemctl
|
|
reset-failed</command> will cause the
|
|
restart rate counter for a service to
|
|
be flushed, which is useful if the
|
|
administrator wants to manually start
|
|
a service and the start limit
|
|
interferes with
|
|
that.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>StartLimitAction=</varname></term>
|
|
|
|
<listitem><para>Configure the action
|
|
to take if the rate limit configured
|
|
with
|
|
<varname>StartLimitInterval=</varname>
|
|
and
|
|
<varname>StartLimitBurst=</varname> is
|
|
hit. Takes one of
|
|
<option>none</option>,
|
|
<option>reboot</option>,
|
|
<option>reboot-force</option>, or
|
|
<option>reboot-immediate</option>. If
|
|
<option>none</option> is set,
|
|
hitting the rate limit will trigger no
|
|
action besides that the start will not
|
|
be permitted. <option>reboot</option>
|
|
causes a reboot following the normal
|
|
shutdown procedure (i.e. equivalent to
|
|
<command>systemctl reboot</command>).
|
|
<option>reboot-force</option> causes
|
|
a forced reboot which will terminate
|
|
all processes forcibly but should
|
|
cause no dirty file systems on reboot
|
|
(i.e. equivalent to <command>systemctl
|
|
reboot -f</command>) and
|
|
<option>reboot-immediate</option>
|
|
causes immediate execution of the
|
|
<citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
system call, which might result in
|
|
data loss. Defaults to
|
|
<option>none</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>RebootArgument=</varname></term>
|
|
<listitem><para>Configure the optional
|
|
argument for the
|
|
<citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
system call if
|
|
<varname>StartLimitAction=</varname>
|
|
is a reboot action. This works just
|
|
like the optional argument to
|
|
<command>systemctl reboot</command>
|
|
command.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>FailureAction=</varname></term>
|
|
<listitem><para>Configure the action
|
|
to take when the service enters a failed
|
|
state. Takes the same values as
|
|
<varname>StartLimitAction=</varname>
|
|
and executes the same actions.
|
|
Defaults to <option>none</option>.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
|
|
<para>Check
|
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
and
|
|
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
for more settings.</para>
|
|
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Compatibility Options</title>
|
|
|
|
<para>The following options are also available in the
|
|
<literal>[Service]</literal> section, but exist purely
|
|
for compatibility reasons and should not be used in
|
|
newly written service files.</para>
|
|
|
|
<variablelist class='unit-directives'>
|
|
<varlistentry>
|
|
<term><varname>SysVStartPriority=</varname></term>
|
|
<listitem><para>Set the SysV start
|
|
priority to use to order this service
|
|
in relation to SysV services lacking
|
|
LSB headers. This option is only
|
|
necessary to fix ordering in relation
|
|
to legacy SysV services that have no
|
|
ordering information encoded in the
|
|
script headers. As such, it should only
|
|
be used as a temporary compatibility
|
|
option and should not be used in new unit
|
|
files. Almost always, it is a better
|
|
choice to add explicit ordering
|
|
directives via
|
|
<varname>After=</varname> or
|
|
<varname>Before=</varname>,
|
|
instead. For more details, see
|
|
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
|
|
If used, pass an integer value in the
|
|
range 0-99.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|