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
  91         <constant>SIGTERM</constant> (unless the signal to send is
  92         changed via <varname>KillSignal=</varname>). Optionally, this
  93         is immediately followed by a <constant>SIGHUP</constant> (if
  94         enabled with <varname>SendSIGHUP=</varname>). If then, after a
  95         delay (configured via the <varname>TimeoutStopSec=</varname>
  96         option), processes still remain, the termination request is
  97         repeated with the <constant>SIGKILL</constant> signal or the
  98         signal specified via <varname>FinalKillSignal=</varname> (unless
  99         this is disabled via the <varname>SendSIGKILL=</varname>
 100         option). See
 101         <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 102         for more information.</para>
 103
 104         <para>Defaults to
 105         <option>control-group</option>.</para></listitem>
 106       </varlistentry>
 107
 108       <varlistentry>
 109         <term><varname>KillSignal=</varname></term>
 110         <listitem><para>Specifies which signal to use when killing a
 111         service. This controls the signal that is sent as first step
 112         of shutting down a unit (see above), and is usually followed
 113         by <constant>SIGKILL</constant> (see above and below). For a
 114         list of valid signals, see
 115         <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 116         Defaults to <constant>SIGTERM</constant>. </para>
 117
 118         <para>Note that, right after sending the signal specified in
 119         this setting, systemd will always send
 120         <constant>SIGCONT</constant>, to ensure that even suspended
 121         tasks can be terminated cleanly.</para>
 122         </listitem>
 123       </varlistentry>
 124
 125       <varlistentry>
 126         <term><varname>SendSIGHUP=</varname></term>
 127         <listitem><para>Specifies whether to send
 128         <constant>SIGHUP</constant> to remaining processes immediately
 129         after sending the signal configured with
 130         <varname>KillSignal=</varname>. This is useful to indicate to
 131         shells and shell-like programs that their connection has been
 132         severed. Takes a boolean value. Defaults to "no".
 133         </para></listitem>
 134       </varlistentry>
 135
 136       <varlistentry>
 137         <term><varname>SendSIGKILL=</varname></term>
 138         <listitem><para>Specifies whether to send
 139         <constant>SIGKILL</constant> (or the signal specified by
 140         <varname>FinalKillSignal=</varname>) to remaining processes
 141         after a timeout, if the normal shutdown procedure left
 142         processes of the service around. Takes a boolean value.
 143         Defaults to "yes".
 144         </para></listitem>
 145       </varlistentry>
 146
 147       <varlistentry>
 148         <term><varname>FinalKillSignal=</varname></term>
 149         <listitem><para>Specifies which signal to send to remaining
 150         processes after a timeout if <varname>SendSIGKILL=</varname>
 151         is enabled. The signal configured here should be one that is
 152         not typically caught and processed by services (<constant>SIGTERM</constant>
 153         is not suitable). Developers can find it useful to use this to
 154         generate a coredump to troubleshoot why a service did not
 155         terminate upon receiving the initial <constant>SIGTERM</constant>
 156         signal. This can be achieved by configuring <varname>LimitCORE=</varname>
 157         and setting <varname>FinalKillSignal=</varname> to either
 158         <constant>SIGQUIT</constant> or <constant>SIGABRT</constant>
 159         Defaults to <constant>SIGKILL</constant>.
 160         </para></listitem>
 161       </varlistentry>
 162
 163       <varlistentry>
 164         <term><varname>WatchdogSignal=</varname></term>
 165         <listitem><para>Specifies which signal to use to terminate the
 166         service when the watchdog timeout expires (enabled through
 167         <varname>WatchdogSec=</varname>). Defaults to <constant>SIGABRT</constant>.
 168         </para></listitem>
 169       </varlistentry>
 170
 171     </variablelist>
 172   </refsect1>
 173
 174   <refsect1>
 175       <title>See Also</title>
 176       <para>
 177         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 178         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 179         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 180         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 181         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 182         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 183         <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 184         <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 185         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 186         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 187         <citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 188         <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 189       </para>
 190   </refsect1>
 191
 192 </refentry>