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NAME | SYNOPSIS | DESCRIPTION | PRESET FILE FORMAT | EXAMPLES | SEE ALSO | NOTES | COLOPHON |
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SYSTEMD.PRESET(5) systemd.preset SYSTEMD.PRESET(5)
systemd.preset - Service enablement presets
/etc/systemd/system-preset/*.preset
/run/systemd/system-preset/*.preset
/usr/lib/systemd/system-preset/*.preset
/etc/systemd/user-preset/*.preset
/run/systemd/user-preset/*.preset
/usr/lib/systemd/user-preset/*.preset
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 systemctl preset (for more information see systemctl(1))
which uses this information to enable or disable a unit according
to preset policy. systemctl preset 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.
For more information on the preset logic please have a look at
the Presets[1] document.
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.
If no preset files exist, systemctl preset 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 "disable *" line. (See example 1,
below.)
The preset files contain a list of directives consisting of
either the word "enable" or "disable" 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 "#" or ";" 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 "@" and
the unit suffix.
Presets must refer to the "real" unit file, and not to any
aliases. See systemd.unit(5) for a description of unit aliasing.
Two different directives are understood: "enable" may be used to
enable units by default, "disable" to disable units by default.
If multiple lines apply to a unit name, the first matching one
takes precedence over all others.
Each preset file shall be named in the style of
<priority>-<policy-name>.preset. Files in /etc/ override files
with the same name in /usr/lib/ and /run/. Files in /run/
override files with the same name in /usr/lib/. Packages should
install their preset files in /usr/lib/. Files in /etc/ 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.
If the administrator wants to disable a preset file supplied by
the vendor, the recommended way is to place a symlink to
/dev/null in /etc/systemd/system-preset/ bearing the same
filename.
Example 1. Default to off
# /usr/lib/systemd/system-preset/99-default.preset
disable *
This disables all units. Due to the filename prefix "99-", it
will be read last and hence can easily be overridden by spin or
administrator preset policy.
Example 2. Enable multiple template instances
# /usr/lib/systemd/system-preset/80-dirsrv.preset
enable dirsrv@.service foo bar baz
This enables all three of dirsrv@foo.service, dirsrv@bar.service
and dirsrv@baz.service.
Example 3. A GNOME spin
# /usr/lib/systemd/system-preset/50-gnome.preset
enable gdm.service
enable colord.service
enable accounts-daemon.service
enable avahi-daemon.*
This enables the three mentioned units, plus all avahi-daemon
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.
Example 4. Administrator policy
# /etc/systemd/system-preset/00-lennart.preset
enable httpd.service
enable sshd.service
enable postfix.service
disable *
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 "00-" it will be read early and override all other preset
policy files.
systemd(1), systemctl(1), systemd-delta(1)
1. Presets
https://www.freedesktop.org/wiki/Software/systemd/Preset
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have
a bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2020-12-18. (At that
time, the date of the most recent commit that was found in the
repository was 2020-12-18.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 247 SYSTEMD.PRESET(5)
Pages that refer to this page: systemctl(1), systemd.directives(7), systemd.index(7)
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