188 lines
7.5 KiB
XML
188 lines
7.5 KiB
XML
<?xml version="1.0"?>
|
|
<!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
|
|
<refentry id="systemd.preset">
|
|
|
|
<refentryinfo>
|
|
<title>systemd.preset</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>systemd.preset</refentrytitle>
|
|
<manvolnum>5</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>systemd.preset</refname>
|
|
<refpurpose>Service enablement presets</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<para><filename>/etc/systemd/system-preset/*.preset</filename></para>
|
|
<para><filename>/run/systemd/system-preset/*.preset</filename></para>
|
|
<para><filename>/usr/lib/systemd/system-preset/*.preset</filename></para>
|
|
<para><filename>/etc/systemd/user-preset/*.preset</filename></para>
|
|
<para><filename>/run/systemd/user-preset/*.preset</filename></para>
|
|
<para><filename>/usr/lib/systemd/user-preset/*.preset</filename></para>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>Preset files may be used to encode policy which units shall
|
|
be enabled by default and which ones shall be disabled. They are
|
|
read by <command>systemctl preset</command> (for more information
|
|
see
|
|
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>)
|
|
which uses this information to enable or disable a unit according
|
|
to preset policy. <command>systemctl preset</command> is used by
|
|
the post install scriptlets of RPM packages (or other OS package
|
|
formats), to enable/disable specific units by default on package
|
|
installation, enforcing distribution, spin or administrator preset
|
|
policy. This allows choosing a certain set of units to be
|
|
enabled/disabled even before installing the actual package.</para>
|
|
|
|
<para>For more information on the preset logic please have a look
|
|
at the <ulink
|
|
url="https://www.freedesktop.org/wiki/Software/systemd/Preset">Presets</ulink>
|
|
document.</para>
|
|
|
|
<para>It is not recommended to ship preset files within the
|
|
respective software packages implementing the units, but rather
|
|
centralize them in a distribution or spin default policy, which
|
|
can be amended by administrator policy.</para>
|
|
|
|
<para>If no preset files exist, <command>systemctl
|
|
preset</command> will enable all units that are installed by
|
|
default. If this is not desired and all units shall rather be
|
|
disabled, it is necessary to ship a preset file with a single,
|
|
catchall "<filename>disable *</filename>" line. (See example 1,
|
|
below.)</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Preset File Format</title>
|
|
|
|
<para>The preset files contain a list of directives consisting of
|
|
either the word <literal>enable</literal> or
|
|
<literal>disable</literal> followed by a space and a unit name
|
|
(possibly with shell style wildcards), separated by newlines.
|
|
Empty lines and lines whose first non-whitespace character is <literal>#</literal> or
|
|
<literal>;</literal> are ignored. Multiple instance names for unit
|
|
templates may be specified as a space separated list at the end of
|
|
the line instead of the customary position between <literal>@</literal>
|
|
and the unit suffix.</para>
|
|
|
|
<para>Presets must refer to the "real" unit file, and not to any aliases. See
|
|
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
for a description of unit aliasing.</para>
|
|
|
|
<para>Two different directives are understood:
|
|
<literal>enable</literal> may be used to enable units by default,
|
|
<literal>disable</literal> to disable units by default.</para>
|
|
|
|
<para>If multiple lines apply to a unit name, the first matching
|
|
one takes precedence over all others.</para>
|
|
|
|
<para>Each preset file shall be named in the style of
|
|
<filename><priority>-<policy-name>.preset</filename>. Files
|
|
in <filename>/etc/</filename> override files with the same name in
|
|
<filename>/usr/lib/</filename> and <filename>/run/</filename>.
|
|
Files in <filename>/run/</filename> override files with the same
|
|
name in <filename>/usr/lib/</filename>. Packages should install
|
|
their preset files in <filename>/usr/lib/</filename>. Files in
|
|
<filename>/etc/</filename> are reserved for the local
|
|
administrator, who may use this logic to override the preset files
|
|
installed by vendor packages. All preset files are sorted by their
|
|
filename in lexicographic order, regardless of which of the
|
|
directories they reside in. If multiple files specify the same
|
|
unit name, the entry in the file with the lexicographically
|
|
earliest name will be applied. It is recommended to prefix all
|
|
filenames with a two-digit number and a dash, to simplify the
|
|
ordering of the files.</para>
|
|
|
|
<para>If the administrator wants to disable a preset file supplied
|
|
by the vendor, the recommended way is to place a symlink to
|
|
<filename>/dev/null</filename> in
|
|
<filename>/etc/systemd/system-preset/</filename> bearing the same
|
|
filename.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Examples</title>
|
|
|
|
<example>
|
|
<title>Default to off</title>
|
|
|
|
<programlisting># /usr/lib/systemd/system-preset/99-default.preset
|
|
|
|
disable *</programlisting>
|
|
</example>
|
|
|
|
<para>This disables all units. Due to the filename prefix
|
|
<literal>99-</literal>, it will be read last and hence can easily
|
|
be overridden by spin or administrator preset policy.</para>
|
|
|
|
<example>
|
|
<title>Enable multiple template instances</title>
|
|
|
|
<programlisting># /usr/lib/systemd/system-preset/80-dirsrv.preset
|
|
|
|
enable dirsrv@.service foo bar baz</programlisting>
|
|
</example>
|
|
|
|
<para>This enables all three of <filename>dirsrv@foo.service</filename>,
|
|
<filename>dirsrv@bar.service</filename> and <filename>dirsrv@baz.service</filename>.</para>
|
|
|
|
<example>
|
|
<title>A GNOME spin</title>
|
|
|
|
<programlisting># /usr/lib/systemd/system-preset/50-gnome.preset
|
|
|
|
enable gdm.service
|
|
enable colord.service
|
|
enable accounts-daemon.service
|
|
enable avahi-daemon.*</programlisting>
|
|
|
|
</example>
|
|
|
|
<para>This enables the three mentioned units, plus all
|
|
<filename>avahi-daemon</filename> regardless of which unit type. A
|
|
file like this could be useful for inclusion in a GNOME spin of a
|
|
distribution. It will ensure that the units necessary for GNOME
|
|
are properly enabled as they are installed. It leaves all other
|
|
units untouched, and subject to other (later) preset files, for
|
|
example like the one from the first example above.</para>
|
|
|
|
<example>
|
|
<title>Administrator policy</title>
|
|
|
|
<programlisting># /etc/systemd/system-preset/00-lennart.preset
|
|
|
|
enable httpd.service
|
|
enable sshd.service
|
|
enable postfix.service
|
|
disable *</programlisting>
|
|
</example>
|
|
|
|
<para>This enables three specific services and disables all
|
|
others. This is useful for administrators to specifically select
|
|
the units to enable, and disable all others. Due to the filename
|
|
prefix <literal>00-</literal> it will be read early and
|
|
override all other preset policy files.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|