man/systemd-halt.service.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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   8   Copyright 2012 Lennart Poettering
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  23
  24 <refentry id="systemd-halt.service">
  25
  26         <refentryinfo>
  27                 <title>systemd-halt.service</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemd-halt.service</refentrytitle>
  42                 <manvolnum>8</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd-halt.service</refname>
  47                 <refname>systemd-poweroff.service</refname>
  48                 <refname>systemd-reboot.service</refname>
  49                 <refname>systemd-kexec.service</refname>
  50                 <refname>systemd-shutdown</refname>
  51                 <refpurpose>System shutdown logic</refpurpose>
  52         </refnamediv>
  53
  54         <refsynopsisdiv>
  55                 <para><filename>systemd-halt.service</filename></para>
  56                 <para><filename>systemd-poweroff.service</filename></para>
  57                 <para><filename>systemd-reboot.service</filename></para>
  58                 <para><filename>systemd-kexec.service</filename></para>
  59                 <para><filename>/usr/lib/systemd/systemd-shutdown</filename></para>
  60         </refsynopsisdiv>
  61
  62         <refsect1>
  63                 <title>Description</title>
  64
  65                 <para><filename>systemd-halt.service</filename> is a
  66                 system service that is pulled in by
  67                 <filename>halt.target</filename> and is responsible
  68                 for the actual system halt. Similar,
  69                 <filename>systemd-poweroff.service</filename> is
  70                 pulled in by <filename>poweroff.target</filename>,
  71                 <filename>systemd-reboot.service</filename> by
  72                 <filename>reboot.target</filename> and
  73                 <filename>systemd-kexec.service</filename> by
  74                 <filename>kexec.target</filename> to execute the
  75                 respective actions.</para>
  76
  77                 <para>When these services are run they ensure that PID
  78                 1 is replaced by the
  79                 <filename>/usr/lib/systemd/systemd-shutdown</filename>
  80                 tool which is then responsible for the actual
  81                 shutdown. Before shutting down this binary will try to
  82                 unmount all remaining file systems, disable all
  83                 remaining swap devices, detach all remaining storage
  84                 devices and kill all remaining processes.</para>
  85
  86                 <para>Immediately before executing the actual system
  87                 halt/poweroff/reboot/kexec
  88                 <filename>systemd-shutdown</filename> will run all
  89                 executables in
  90                 <filename>/usr/lib/systemd/system-shutdown/</filename>
  91                 and pass one arguments to them: either
  92                 <literal>halt</literal>,
  93                 <literal>poweroff</literal>,
  94                 <literal>reboot</literal> or
  95                 <literal>kexec</literal>, depending on the chosen
  96                 action. All executables in this directory are executed
  97                 in parallel, and execution of the action is not
  98                 continued before all executables finished.</para>
  99
 100                 <para>Note that
 101                 <filename>systemd-halt.service</filename> (and the
 102                 related units) should never be executed
 103                 directly. Instead, trigger system shutdown with a
 104                 command such as <literal>systemctl halt</literal> or
 105                 suchlike.</para>
 106         </refsect1>
 107
 108         <refsect1>
 109                 <title>See Also</title>
 110                 <para>
 111                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 112                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 113                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 114                         <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 115                         <citerefentry><refentrytitle>systemd-suspend.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 116                 </para>
 117         </refsect1>
 118
 119 </refentry>