man/systemd.kill.xml

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