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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+ -->
<refentry id="systemd.kill">
<refentryinfo>
<title>systemd.kill</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>systemd.kill</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd.kill</refname>
<refpurpose>Process killing procedure
configuration</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename><replaceable>service</replaceable>.service</filename>,
<filename><replaceable>socket</replaceable>.socket</filename>,
<filename><replaceable>mount</replaceable>.mount</filename>,
<filename><replaceable>swap</replaceable>.swap</filename>,
<filename><replaceable>scope</replaceable>.scope</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>Unit configuration files for services, sockets, mount
points, swap devices and scopes share a subset of configuration
options which define the killing procedure of processes belonging
to the unit.</para>
<para>This man page lists the configuration options shared by
these five unit types. See
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for the common options shared by all unit configuration files, and
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
and
<citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for more information on the configuration file options specific to
each unit type.</para>
<para>The kill procedure configuration options are configured in
the [Service], [Socket], [Mount] or [Swap] section, depending on
the unit type.</para>
</refsect1>
<refsect1>
<title>Options</title>
<variablelist class='unit-directives'>
<varlistentry>
<term><varname>KillMode=</varname></term>
<listitem><para>Specifies how processes of this unit shall be
killed. One of
<option>control-group</option>,
<option>process</option>,
<option>mixed</option>,
<option>none</option>.</para>
<para>If set to <option>control-group</option>, all remaining
processes in the control group of this unit will be killed on
unit stop (for services: after the stop command is executed,
as configured with <varname>ExecStop=</varname>). If set to
<option>process</option>, only the main process itself is
killed. If set to <option>mixed</option>, the
<constant>SIGTERM</constant> signal (see below) is sent to the
main process while the subsequent <constant>SIGKILL</constant>
signal (see below) is sent to all remaining processes of the
unit's control group. If set to <option>none</option>, no
process is killed. In this case, only the stop command will be
executed on unit stop, but no process be killed otherwise.
Processes remaining alive after stop are left in their control
group and the control group continues to exist after stop
unless it is empty.</para>
<para>Processes will first be terminated via
<constant>SIGTERM</constant> (unless the signal to send is
changed via <varname>KillSignal=</varname>). Optionally, this
is immediately followed by a <constant>SIGHUP</constant> (if
enabled with <varname>SendSIGHUP=</varname>). If then, after a
delay (configured via the <varname>TimeoutStopSec=</varname>
option), processes still remain, the termination request is
repeated with the <constant>SIGKILL</constant> signal or the
signal specified via <varname>FinalKillSignal=</varname> (unless
this is disabled via the <varname>SendSIGKILL=</varname>
option). See
<citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>
for more information.</para>
<para>Defaults to
<option>control-group</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>KillSignal=</varname></term>
<listitem><para>Specifies which signal to use when killing a
service. This controls the signal that is sent as first step
of shutting down a unit (see above), and is usually followed
by <constant>SIGKILL</constant> (see above and below). For a
list of valid signals, see
<citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
Defaults to <constant>SIGTERM</constant>. </para>
<para>Note that, right after sending the signal specified in
this setting, systemd will always send
<constant>SIGCONT</constant>, to ensure that even suspended
tasks can be terminated cleanly.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>SendSIGHUP=</varname></term>
<listitem><para>Specifies whether to send
<constant>SIGHUP</constant> to remaining processes immediately
after sending the signal configured with
<varname>KillSignal=</varname>. This is useful to indicate to
shells and shell-like programs that their connection has been
severed. Takes a boolean value. Defaults to "no".
</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>SendSIGKILL=</varname></term>
<listitem><para>Specifies whether to send
<constant>SIGKILL</constant> (or the signal specified by
<varname>FinalKillSignal=</varname>) to remaining processes
after a timeout, if the normal shutdown procedure left
processes of the service around. When disabled, a
<varname>KillMode=</varname> of <constant>control-group</constant>
or <constant>mixed</constant> service will not restart if
processes from prior services exist within the control group.
Takes a boolean value. Defaults to "yes".
</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>FinalKillSignal=</varname></term>
<listitem><para>Specifies which signal to send to remaining
processes after a timeout if <varname>SendSIGKILL=</varname>
is enabled. The signal configured here should be one that is
not typically caught and processed by services (<constant>SIGTERM</constant>
is not suitable). Developers can find it useful to use this to
generate a coredump to troubleshoot why a service did not
terminate upon receiving the initial <constant>SIGTERM</constant>
signal. This can be achieved by configuring <varname>LimitCORE=</varname>
and setting <varname>FinalKillSignal=</varname> to either
<constant>SIGQUIT</constant> or <constant>SIGABRT</constant>
Defaults to <constant>SIGKILL</constant>.
</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>WatchdogSignal=</varname></term>
<listitem><para>Specifies which signal to use to terminate the
service when the watchdog timeout expires (enabled through
<varname>WatchdogSec=</varname>). Defaults to <constant>SIGABRT</constant>.
</para></listitem>
</varlistentry>
</variablelist>
</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>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
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