man/systemd.preset.5

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  22 .SH "NAME"
  23 systemd.preset \- Service enablement presets
  24 .SH "SYNOPSIS"
  25 .PP
  26 /etc/systemd/system\-preset/*\&.preset
  27 .PP
  28 /run/systemd/system\-preset/*\&.preset
  29 .PP
  30 /usr/lib/systemd/system\-preset/*\&.preset
  31 .PP
  32 /etc/systemd/user\-preset/*\&.preset
  33 .PP
  34 /run/systemd/user\-preset/*\&.preset
  35 .PP
  36 /usr/lib/systemd/user\-preset/*\&.preset
  37 .SH "DESCRIPTION"
  38 .PP
  39 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
  40 \fBsystemctl preset\fR
  41 (for more information see
  42 \fBsystemctl\fR(1)) which uses this information to enable or disable a unit according to preset policy\&.
  43 \fBsystemctl preset\fR
  44 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\&.
  45 .PP
  46 For more information on the preset logic please have a look at the
  47 \m[blue]\fBPresets\fR\m[]\&\s-2\u[1]\d\s+2
  48 document\&.
  49 .PP
  50 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\&.
  51 .PP
  52 If no preset files exist,
  53 \fBsystemctl preset\fR
  54 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\&.)
  55 .SH "PRESET FILE FORMAT"
  56 .PP
  57 The preset files contain a list of directives consisting of either the word
  58 "enable"
  59 or
  60 "disable"
  61 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\&.
  62 .PP
  63 Two different directives are understood:
  64 "enable"
  65 may be used to enable units by default,
  66 "disable"
  67 to disable units by default\&.
  68 .PP
  69 If multiple lines apply to a unit name, the first matching one takes precedence over all others\&.
  70 .PP
  71 Each preset file shall be named in the style of
  72 <priority>\-<program>\&.conf\&. Files in
  73 /etc/
  74 override files with the same name in
  75 /usr/lib/
  76 and
  77 /run/\&. Files in
  78 /run/
  79 override files with the same name in
  80 /usr/lib/\&. Packages should install their preset files in
  81 /usr/lib/\&. Files in
  82 /etc/
  83 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\&.
  84 .PP
  85 If the administrator wants to disable a preset file supplied by the vendor, the recommended way is to place a symlink to
  86 /dev/null
  87 in
  88 /etc/systemd/system\-preset/
  89 bearing the same filename\&.
  90 .SH "EXAMPLE"
  91 .PP
  92 \fBExample\ \&1.\ \&Default off example /usr/lib/systemd/system\-preset/99\-default\&.preset:\fR
  93 .sp
  94 .if n \{\
  95 .RS 4
  96 .\}
  97 .nf
  98 disable *
  99 .fi
 100 .if n \{\
 101 .RE
 102 .\}
 103 .PP
 104 This disables all units\&. Due to the filename prefix
 105 "99\-", it will be read last and hence can easily be overridden by spin or administrator preset policy or suchlike\&.
 106 .PP
 107 \fBExample\ \&2.\ \&A GNOME spin example /usr/lib/systemd/system\-preset/50\-gnome\&.preset:\fR
 108 .sp
 109 .if n \{\
 110 .RS 4
 111 .\}
 112 .nf
 113 enable gdm\&.service
 114 enable colord\&.service
 115 enable accounts\-daemon\&.service
 116 enable avahi\-daemon\&.*
 117 .fi
 118 .if n \{\
 119 .RE
 120 .\}
 121 .PP
 122 This enables the three mentioned units, plus all
 123 avahi\-daemon
 124 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\&.
 125 .PP
 126 \fBExample\ \&3.\ \&Administrator policy /etc/systemd/system\-preset/00\-lennart\&.preset:\fR
 127 .sp
 128 .if n \{\
 129 .RS 4
 130 .\}
 131 .nf
 132 enable httpd\&.service
 133 enable sshd\&.service
 134 enable postfix\&.service
 135 disable *
 136 .fi
 137 .if n \{\
 138 .RE
 139 .\}
 140 .PP
 141 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
 142 "00\-"
 143 it will be read early and hence overrides all other preset policy files\&.
 144 .SH "SEE ALSO"
 145 .PP
 146 \fBsystemd\fR(1),
 147 \fBsystemctl\fR(1),
 148 \fBsystemd-delta\fR(1)
 149 .SH "NOTES"
 150 .IP " 1." 4
 151 Presets
 152 .RS 4
 153 \%http://freedesktop.org/wiki/Software/systemd/Preset
 154 .RE