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-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<!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+
--->
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="systemd.kill">
<refentryinfo>
<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>,
+ <listitem><para>Specifies how processes of this unit shall be killed. One of
+ <option>control-group</option>, <option>mixed</option>, <option>process</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>
+ <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>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>process</option>, only the main process itself is killed (not
+ recommended!). If set to <option>none</option>, no process is killed (strongly recommended
+ against!). In this case, only the stop command will be executed on unit stop, but no process will be
+ killed otherwise. Processes remaining alive after stop are left in their control group and the
+ control group continues to exist after stop unless empty.</para>
+
+ <para>Note that it is not recommended to set <varname>KillMode=</varname> to
+ <constant>process</constant> or even <constant>none</constant>, as this allows processes to escape
+ the service manager's lifecycle and resource management, and to remain running even while their
+ service is considered stopped and is assumed to not consume any resources.</para>
+
+ <para>Processes will first be terminated via <constant>SIGTERM</constant> (unless the signal to send
+ is changed via <varname>KillSignal=</varname> or <varname>RestartKillSignal=</varname>). Optionally,
+ this is immediately followed by a <constant>SIGHUP</constant> (if enabled with
+ <varname>SendSIGHUP=</varname>). If processes still remain after the main process of a unit has
+ exited or the delay configured via the <varname>TimeoutStopSec=</varname> has passed, 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>
+ <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
+ <listitem><para>Specifies which signal to use when stopping 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>
+ 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>
+ <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>RestartKillSignal=</varname></term>
+ <listitem><para>Specifies which signal to use when restarting a service. The same as
+ <varname>KillSignal=</varname> described above, with the exception that this setting is used in a
+ restart job. Not set by default, and the value of <varname>KillSignal=</varname> is used.</para>
</listitem>
</varlistentry>
<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. Takes a boolean value.
- Defaults to "yes".
+ 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>
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>
+ <constant>SIGQUIT</constant> or <constant>SIGABRT</constant>.
Defaults to <constant>SIGKILL</constant>.
</para></listitem>
</varlistentry>
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