3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5 This file is part of systemd.
7 Copyright 2011 Lennart Poettering
9 systemd is free software; you can redistribute it and/or modify it
10 under the terms of the GNU Lesser General Public License as published by
11 the Free Software Foundation; either version 2.1 of the License, or
12 (at your option) any later version.
14 systemd is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 Lesser General Public License for more details.
19 You should have received a copy of the GNU Lesser General Public License
20 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 <refentry id="systemd.preset">
25 <title>systemd.preset</title>
26 <productname>systemd</productname>
30 <contrib>Developer</contrib>
31 <firstname>Lennart</firstname>
32 <surname>Poettering</surname>
33 <email>lennart@poettering.net</email>
39 <refentrytitle>systemd.preset</refentrytitle>
40 <manvolnum>5</manvolnum>
44 <refname>systemd.preset</refname>
45 <refpurpose>Service enablement presets</refpurpose>
49 <para><filename>/etc/systemd/system-preset/*.preset</filename></para>
50 <para><filename>/run/systemd/system-preset/*.preset</filename></para>
51 <para><filename>/usr/lib/systemd/system-preset/*.preset</filename></para>
52 <para><filename>/etc/systemd/user-preset/*.preset</filename></para>
53 <para><filename>/run/systemd/user-preset/*.preset</filename></para>
54 <para><filename>/usr/lib/systemd/user-preset/*.preset</filename></para>
58 <title>Description</title>
60 <para>Preset files may be used to encode policy which
61 units shall be enabled by default and which ones
62 shall be disabled. They are read by <command>systemctl
63 preset</command> (for more information see
64 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>)
65 which uses this information to enable or disable a
66 unit according to preset policy. <command>systemctl
67 preset</command> is used by the post install
68 scriptlets of RPM packages (or other OS package formats),
69 to enable/disable specific units by default on package
70 installation, enforcing distribution, spin or
71 administrator preset policy. This allows choosing a certain
72 set of units to be enabled/disabled even before
73 installing the actual package.</para>
75 <para>For more information on the preset logic please
76 have a look at the <ulink
77 url="http://freedesktop.org/wiki/Software/systemd/Preset">Presets</ulink>
80 <para>It is not recommended to ship preset files
81 within the respective software packages implementing
82 the units, but rather centralize them in a
83 distribution or spin default policy, which can be
84 amended by administrator policy.</para>
86 <para>If no preset files exist, <command>systemctl
87 preset</command> will enable all units that are
88 installed by default. If this is not desired and all
89 units shall rather be disabled, it is necessary to ship
90 a preset file with a single, catchall
91 "<filename>disable *</filename>" line. (See example 1,
96 <title>Preset File Format</title>
98 <para>The preset files contain a list of
99 directives consisting of either the word
100 <literal>enable</literal> or
101 <literal>disable</literal> followed by a space and a
102 unit name (possibly with shell style wildcards),
103 separated by newlines. Empty lines and lines whose
104 first non-whitespace character is # or ; are
107 <para>Two different directives are understood:
108 <literal>enable</literal> may be used to enable units
109 by default, <literal>disable</literal> to disable
110 units by default.</para>
112 <para>If multiple lines apply to a unit name, the
113 first matching one takes precedence over all
116 <para>Each preset file shall be named in the style of
117 <filename><priority>-<program>.conf</filename>.
118 Files in <filename>/etc/</filename> override files
119 with the same name in <filename>/usr/lib/</filename>
120 and <filename>/run/</filename>. Files in
121 <filename>/run/</filename> override files with the
122 same name in <filename>/usr/lib/</filename>. Packages
123 should install their preset files in
124 <filename>/usr/lib/</filename>. Files in
125 <filename>/etc/</filename> are reserved for the local
126 administrator, who may use this logic to override the
127 preset files installed by vendor packages. All preset
128 files are sorted by their filename in lexicographic
129 order, regardless in which of the directories they
130 reside. If multiple files specify the same unit name,
131 the entry in the file with the lexicographically earliest
132 name will be applied. It is recommended to prefix all
133 filenames with a two-digit number and a dash, to simplify
134 the ordering of the files.</para>
136 <para>If the administrator wants to disable a preset
137 file supplied by the vendor, the recommended way is to
138 place a symlink to <filename>/dev/null</filename> in
139 <filename>/etc/systemd/system-preset/</filename>
140 bearing the same filename.</para>
144 <title>Example</title>
147 <title>Default off example <filename>/usr/lib/systemd/system-preset/99-default.preset</filename>:</title>
149 <programlisting>disable *</programlisting>
152 <para>This disables all units. Due to the filename
153 prefix <literal>99-</literal>, it will be read last and
154 hence can easily be overridden by spin or
155 administrator preset policy or suchlike.</para>
158 <title>A GNOME spin example <filename>/usr/lib/systemd/system-preset/50-gnome.preset</filename>:</title>
160 <programlisting>enable gdm.service
161 enable colord.service
162 enable accounts-daemon.service
163 enable avahi-daemon.*</programlisting>
167 <para>This enables the three mentioned units, plus all
168 <filename>avahi-daemon</filename> regardless of which
169 unit type. A file like this could be useful for
170 inclusion in a GNOME spin of a distribution. It will
171 ensure that the units necessary for GNOME are properly
172 enabled as they are installed. It leaves all other
173 units untouched, and subject to other (later) preset
174 files, for example like the one from the first example
178 <title>Administrator policy <filename>/etc/systemd/system-preset/00-lennart.preset</filename>:</title>
180 <programlisting>enable httpd.service
182 enable postfix.service
183 disable *</programlisting>
186 <para>This enables three specific services and
187 disables all others. This is useful for administrators
188 to specifically select the units to enable, and
189 disable all others. Due to the filename prefix
190 <literal>00-</literal> it will be read early and hence
191 overrides all other preset policy files.</para>
195 <title>See Also</title>
197 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
198 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
199 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>