NAME

       systemd.preset - Service enablement presets

SYNOPSIS

       /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

DESCRIPTION

       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.)

PRESET FILE FORMAT

       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.

       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>-<program>.conf. 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 alphabetical order, regardless in which of the directories they reside,
       to guarantee that a specific preset file takes precedence over another file with an
       alphabetically earlier name, if both files contain lines that apply to the same unit
       names. It is recommended to prefix all file names with two-digit number, to simplify
       ordering.

       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
       file name.

EXAMPLE

       Example 1. Default off example /usr/lib/systemd/system-preset/99-default.preset:

           disable *

       This disables all units. Due to the file name prefix 99- it will be read last and hence
       can easily be overridden by spin or administrator preset policy or suchlike.

       Example 2. A GNOME spin example /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 3. 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 file name prefix 00- it will be read early and hence overrides all other preset policy
       files.

SEE ALSO

       systemd(1), systemctl(1), systemd-delta(1)

NOTES

        1. Presets
           http://freedesktop.org/wiki/Software/systemd/Preset