man/systemd.service.xml

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   7   This file is part of systemd.
   8
   9   Copyright 2010 Lennart Poettering
  10
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  24
  25 <refentry id="systemd.service">
  26         <refentryinfo>
  27                 <title>systemd.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.service</refentrytitle>
  42                 <manvolnum>5</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.service</refname>
  47                 <refpurpose>systemd service configuration files</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>systemd.service</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para>A configuration file ending in .service encodes
  58                 information about a process controlled and supervised
  59                 by systemd.</para>
  60
  61                 <para>This man page lists the configuration options
  62                 specific to this unit type. See
  63                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  64                 for the common options of all unit configuration
  65                 files.</para>
  66         </refsect1>
  67
  68         <refsect1>
  69                 <title>Options</title>
  70
  71                 <variablelist>
  72                         <varlistentry>
  73                                 <term><varname>Type=</varname></term>
  74                                 <listitem>
  75                                         <para>One of
  76                                         <literal>forking</literal>,
  77                                         <literal>simple</literal>,
  78                                         <literal>finish</literal>,
  79                                         <literal>dbus</literal>.</para>
  80
  81                                         <para>If set to
  82                                         <literal>forking</literal>
  83                                         (the default) it is expected
  84                                         that the process configured
  85                                         with
  86                                         <varname>ExecStart=</varname>
  87                                         will start up and call
  88                                         <function>fork()</function>. The
  89                                         parent process is expected to
  90                                         finish when start-up is
  91                                         complete and all communication
  92                                         channels set up. The child
  93                                         continues to run as the main
  94                                         daemon process. This is the
  95                                         behaviour of traditional UNIX
  96                                         daemons. If this setting is
  97                                         used it is recommended to also
  98                                         use the
  99                                         <varname>PIDFile=</varname>
 100                                         option, so that systemd can
 101                                         identify the main process of
 102                                         the daemon. systemd will start
 103                                         follow-up units as soon as the
 104                                         parent process exited.</para>
 105
 106                                         <para>If set to
 107                                         <literal>simple</literal> (the
 108                                         recommended value) it is
 109                                         expected that the process
 110                                         configured with
 111                                         <varname>ExecStart=</varname>
 112                                         is the main process of the
 113                                         daemon. In this mode
 114                                         communication channels must be
 115                                         available before the daemon is
 116                                         started up, as systemd will
 117                                         immediately start follow-up
 118                                         units.</para>
 119
 120                                         <para>Behaviour of
 121                                         <literal>finish</literal> is
 122                                         similar to
 123                                         <literal>simple</literal>,
 124                                         however it is expected that
 125                                         the process has to exit before
 126                                         systemd starts follow-up
 127                                         units. <varname>ValidNoProcess=</varname>
 128                                         is particularly useful for
 129                                         this type of service.</para>
 130
 131                                         <para>Behaviour of
 132                                         <literal>dbus</literal> is
 133                                         similar to
 134                                         <literal>simple</literal>,
 135                                         however it is expected that
 136                                         the daemon acquires a name on
 137                                         the D-Bus bus, as configured
 138                                         by
 139                                         <varname>BusName=</varname>. Follow-up
 140                                         units will be started after
 141                                         the name has been
 142                                         acquired.</para>
 143                                 </listitem>
 144                         </varlistentry>
 145                         <varlistentry>
 146                                 <term><varname>ValidNoProcess=</varname></term>
 147                                 <listitem>
 148                                         <para>Takes a boolean value
 149                                         that specifies whether the service
 150                                         shall be considered active
 151                                         even when all its processes
 152                                         exited. Defaults to <literal>no</literal>.</para>
 153                                 </listitem>
 154                         </varlistentry>
 155
 156                         <varlistentry>
 157                                 <term><varname>PIDFile=</varname></term>
 158                                 <listitem>
 159                                         <para>Takes an absolute file
 160                                         name pointing to the PID file
 161                                         of this daemon. Use of this
 162                                         option is recommended for
 163                                         services where
 164                                         <varname>Type=</varname> is
 165                                         set to
 166                                         <literal>forking</literal>.</para>
 167                                 </listitem>
 168                         </varlistentry>
 169
 170                         <varlistentry>
 171                                 <term><varname>BusName=</varname></term>
 172                                 <listitem>
 173                                         <para>Takes a D-Bus bus name
 174                                         that this service is reachable
 175                                         as. This option is mandatory
 176                                         for services where
 177                                         <varname>Type=</varname> is
 178                                         set to
 179                                         <literal>dbus</literal>, but
 180                                         its use is otherwise
 181                                         recommended as well if the
 182                                         process takes a name on the
 183                                         D-Bus bus.</para>
 184                                 </listitem>
 185                         </varlistentry>
 186
 187                         <varlistentry>
 188                                 <term><varname>ExecStart=</varname></term>
 189                                 <listitem>
 190                                         <para>Takes a command line
 191                                         that is executed when this
 192                                         service shall be started
 193                                         up. The first word of the
 194                                         command line must be an
 195                                         absolute file name. It is
 196                                         mandatory to set this option
 197                                         for all services.</para>
 198                                 </listitem>
 199                         </varlistentry>
 200
 201                 </variablelist>
 202         </refsect1>
 203
 204         <refsect1>
 205                   <title>See Also</title>
 206                   <para>
 207                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 208                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 209                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 210                   </para>
 211         </refsect1>
 212
 213 </refentry>