man/systemd.kill.xml

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   9 <refentry id="systemd.kill">
  10   <refentryinfo>
  11     <title>systemd.kill</title>
  12     <productname>systemd</productname>
  13   </refentryinfo>
  14
  15   <refmeta>
  16     <refentrytitle>systemd.kill</refentrytitle>
  17     <manvolnum>5</manvolnum>
  18   </refmeta>
  19
  20   <refnamediv>
  21     <refname>systemd.kill</refname>
  22     <refpurpose>Process killing procedure
  23     configuration</refpurpose>
  24   </refnamediv>
  25
  26   <refsynopsisdiv>
  27     <para><filename><replaceable>service</replaceable>.service</filename>,
  28     <filename><replaceable>socket</replaceable>.socket</filename>,
  29     <filename><replaceable>mount</replaceable>.mount</filename>,
  30     <filename><replaceable>swap</replaceable>.swap</filename>,
  31     <filename><replaceable>scope</replaceable>.scope</filename></para>
  32   </refsynopsisdiv>
  33
  34   <refsect1>
  35     <title>Description</title>
  36
  37     <para>Unit configuration files for services, sockets, mount
  38     points, swap devices and scopes share a subset of configuration
  39     options which define the killing procedure of processes belonging
  40     to the unit.</para>
  41
  42     <para>This man page lists the configuration options shared by
  43     these five unit types. See
  44     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  45     for the common options shared by all unit configuration files, and
  46     <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  47     <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  48     <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  49     <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  50     and
  51     <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  52     for more information on the configuration file options specific to
  53     each unit type.</para>
  54
  55     <para>The kill procedure configuration options are configured in
  56     the [Service], [Socket], [Mount] or [Swap] section, depending on
  57     the unit type.</para>
  58   </refsect1>
  59
  60   <refsect1>
  61     <title>Options</title>
  62
  63     <variablelist class='unit-directives'>
  64
  65       <varlistentry>
  66         <term><varname>KillMode=</varname></term>
  67         <listitem><para>Specifies how processes of this unit shall be
  68         killed. One of
  69         <option>control-group</option>,
  70         <option>process</option>,
  71         <option>mixed</option>,
  72         <option>none</option>.</para>
  73
  74         <para>If set to <option>control-group</option>, all remaining
  75         processes in the control group of this unit will be killed on
  76         unit stop (for services: after the stop command is executed,
  77         as configured with <varname>ExecStop=</varname>). If set to
  78         <option>process</option>, only the main process itself is
  79         killed. If set to <option>mixed</option>, the
  80         <constant>SIGTERM</constant> signal (see below) is sent to the
  81         main process while the subsequent <constant>SIGKILL</constant>
  82         signal (see below) is sent to all remaining processes of the
  83         unit's control group. If set to <option>none</option>, no
  84         process is killed. In this case, only the stop command will be
  85         executed on unit stop, but no process be killed otherwise.
  86         Processes remaining alive after stop are left in their control
  87         group and the control group continues to exist after stop
  88         unless it is empty.</para>
  89
  90         <para>Processes will first be terminated via <constant>SIGTERM</constant> (unless the signal to send
  91         is changed via <varname>KillSignal=</varname>). Optionally, this is immediately followed by a
  92         <constant>SIGHUP</constant> (if enabled with <varname>SendSIGHUP=</varname>). If processes still
  93         remain after the main process of a unit has exited or the delay configured via the
  94         <varname>TimeoutStopSec=</varname> has passed, the termination request is repeated with the
  95         <constant>SIGKILL</constant> signal or the signal specified via <varname>FinalKillSignal=</varname>
  96         (unless this is disabled via the <varname>SendSIGKILL=</varname> option). See
  97         <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry> for more
  98         information.</para>
  99
 100         <para>Defaults to <option>control-group</option>.</para></listitem>
 101       </varlistentry>
 102
 103       <varlistentry>
 104         <term><varname>KillSignal=</varname></term>
 105         <listitem><para>Specifies which signal to use when killing a
 106         service. This controls the signal that is sent as first step
 107         of shutting down a unit (see above), and is usually followed
 108         by <constant>SIGKILL</constant> (see above and below). For a
 109         list of valid signals, see
 110         <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 111         Defaults to <constant>SIGTERM</constant>. </para>
 112
 113         <para>Note that, right after sending the signal specified in
 114         this setting, systemd will always send
 115         <constant>SIGCONT</constant>, to ensure that even suspended
 116         tasks can be terminated cleanly.</para>
 117         </listitem>
 118       </varlistentry>
 119
 120       <varlistentry>
 121         <term><varname>SendSIGHUP=</varname></term>
 122         <listitem><para>Specifies whether to send
 123         <constant>SIGHUP</constant> to remaining processes immediately
 124         after sending the signal configured with
 125         <varname>KillSignal=</varname>. This is useful to indicate to
 126         shells and shell-like programs that their connection has been
 127         severed. Takes a boolean value. Defaults to "no".
 128         </para></listitem>
 129       </varlistentry>
 130
 131       <varlistentry>
 132         <term><varname>SendSIGKILL=</varname></term>
 133         <listitem><para>Specifies whether to send
 134         <constant>SIGKILL</constant> (or the signal specified by
 135         <varname>FinalKillSignal=</varname>) to remaining processes
 136         after a timeout, if the normal shutdown procedure left
 137         processes of the service around. When disabled, a
 138         <varname>KillMode=</varname> of <constant>control-group</constant>
 139         or <constant>mixed</constant> service will not restart if
 140         processes from prior services exist within the control group.
 141         Takes a boolean value. Defaults to "yes".
 142         </para></listitem>
 143       </varlistentry>
 144
 145       <varlistentry>
 146         <term><varname>FinalKillSignal=</varname></term>
 147         <listitem><para>Specifies which signal to send to remaining
 148         processes after a timeout if <varname>SendSIGKILL=</varname>
 149         is enabled. The signal configured here should be one that is
 150         not typically caught and processed by services (<constant>SIGTERM</constant>
 151         is not suitable). Developers can find it useful to use this to
 152         generate a coredump to troubleshoot why a service did not
 153         terminate upon receiving the initial <constant>SIGTERM</constant>
 154         signal. This can be achieved by configuring <varname>LimitCORE=</varname>
 155         and setting <varname>FinalKillSignal=</varname> to either
 156         <constant>SIGQUIT</constant> or <constant>SIGABRT</constant>
 157         Defaults to <constant>SIGKILL</constant>.
 158         </para></listitem>
 159       </varlistentry>
 160
 161       <varlistentry>
 162         <term><varname>WatchdogSignal=</varname></term>
 163         <listitem><para>Specifies which signal to use to terminate the
 164         service when the watchdog timeout expires (enabled through
 165         <varname>WatchdogSec=</varname>). Defaults to <constant>SIGABRT</constant>.
 166         </para></listitem>
 167       </varlistentry>
 168
 169     </variablelist>
 170   </refsect1>
 171
 172   <refsect1>
 173       <title>See Also</title>
 174       <para>
 175         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 176         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 177         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 178         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 179         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 180         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 181         <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 182         <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 183         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 184         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 185         <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 186         <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 187       </para>
 188   </refsect1>
 189
 190 </refentry>