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core: do not make sockets dependent on lo
[elogind.git] / 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">
4
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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>