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Diffstat (limited to 'upstream/mageia-cauldron/man5/systemd.preset.5')
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diff --git a/upstream/mageia-cauldron/man5/systemd.preset.5 b/upstream/mageia-cauldron/man5/systemd.preset.5 new file mode 100644 index 00000000..945e0d62 --- /dev/null +++ b/upstream/mageia-cauldron/man5/systemd.preset.5 @@ -0,0 +1,220 @@ +'\" t +.TH "SYSTEMD\&.PRESET" "5" "" "systemd 255" "systemd.preset" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +systemd.preset \- Service enablement presets +.SH "SYNOPSIS" +.PP +/etc/systemd/system\-preset/*\&.preset +.PP +/run/systemd/system\-preset/*\&.preset +.PP +/usr/lib/systemd/system\-preset/*\&.preset +.PP +/etc/systemd/user\-preset/*\&.preset +.PP +/run/systemd/user\-preset/*\&.preset +.PP +/usr/lib/systemd/user\-preset/*\&.preset +.SH "DESCRIPTION" +.PP +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 +\fBsystemctl preset\fR +which uses this information to enable or disable a unit\&. Depending on that policy, +\fBsystemctl preset\fR +is identical to +\fBsystemctl enable\fR +or +\fBsystemctl disable\fR\&. +\fBsystemctl preset\fR +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, see +\fBsystemctl\fR(1)\&. +.PP +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, see below\&. +.PP +If no preset files exist, preset operations 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\&.) +.PP +When the machine is booted for the first time, +\fBsystemd\fR(1) +will enable/disable all units according to preset policy, similarly to +\fBsystemctl preset\-all\fR\&. Also see "First Boot Semantics" in +\fBmachine-id\fR(5)\&. +.SH "PRESET FILE FORMAT" +.PP +The preset files contain a list of directives, one per line\&. Empty lines and lines whose first non\-whitespace character is +"#" +or +";" +are ignored\&. Each directive consists of one of the words +"enable", +"disable", or +"ignore", followed by whitespace and a unit name\&. The unit name may contain shell\-style wildcards\&. +.PP +For the enable directive for template units, one or more instance names may be specified as a space\-separated list after the unit name\&. In this case, those instances will be enabled instead of the instance specified via DefaultInstance= in the unit\&. +.PP +Presets must refer to the "real" unit file, and not to any aliases\&. See +\fBsystemd.unit\fR(5) +for a description of unit aliasing\&. +.PP +Three different directives are understood: +"enable" +may be used to enable units by default, +"disable" +to disable units by default, and +"ignore" +to ignore units and leave existing configuration intact\&. +.PP +If multiple lines apply to a unit name, the first matching one takes precedence over all others\&. +.PP +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\&. +.PP +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\&. +.SH "EXAMPLES" +.PP +\fBExample\ \&1.\ \&Default to off\fR +.sp +.if n \{\ +.RS 4 +.\} +.nf +# /usr/lib/systemd/system\-preset/99\-default\&.preset + +disable * +.fi +.if n \{\ +.RE +.\} +.PP +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\&. +.PP +\fBExample\ \&2.\ \&Enable multiple template instances\fR +.sp +.if n \{\ +.RS 4 +.\} +.nf +# /usr/lib/systemd/system\-preset/80\-dirsrv\&.preset + +enable dirsrv@\&.service foo bar baz +.fi +.if n \{\ +.RE +.\} +.PP +This enables all three of +dirsrv@foo\&.service, +dirsrv@bar\&.service +and +dirsrv@baz\&.service\&. +.PP +\fBExample\ \&3.\ \&A GNOME spin\fR +.sp +.if n \{\ +.RS 4 +.\} +.nf +# /usr/lib/systemd/system\-preset/50\-gnome\&.preset + +enable gdm\&.service +enable colord\&.service +enable accounts\-daemon\&.service +enable avahi\-daemon\&.* +.fi +.if n \{\ +.RE +.\} +.PP +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\&. +.PP +\fBExample\ \&4.\ \&Administrator policy\fR +.sp +.if n \{\ +.RS 4 +.\} +.nf +# /etc/systemd/system\-preset/00\-lennart\&.preset + +enable httpd\&.service +enable sshd\&.service +enable postfix\&.service +disable * +.fi +.if n \{\ +.RE +.\} +.PP +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\&. +.SH "MOTIVATION FOR THE PRESET LOGIC" +.PP +Different distributions have different policies on which services shall be enabled by default when the package they are shipped in is installed\&. On Fedora all services stay off by default, so that installing a package will not cause a service to be enabled (with some exceptions)\&. On Debian all services are immediately enabled by default, so that installing a package will cause its services to be enabled right\-away\&. +.PP +Even within a single distribution, different spins (flavours, remixes, whatever you might want to call them) of a distribution also have different policies on what services to enable, and what services to leave off\&. For example, Fedora Workstation will enable +\fBgdm\fR +as display manager by default, while the Fedora KDE spin will enable +\fBsddm\fR +instead\&. +.PP +Different sites might also have different policies what to turn on by default and what to turn off\&. For example, one administrator would prefer to enforce the policy of "\fBsshd\fR +should be always on, but everything else off", while another one might say "\fBsnmpd\fR +always on, and for everything else use the distribution policy defaults"\&. +.PP +Traditionally, policy about which services shall be enabled were implemented in each package individually\&. This made it cumbersome to implement different policies per spin or per site, or to create software packages that do the right thing on more than one distribution\&. The enablement mechanism was also encoding the enablement policy\&. +.PP +The preset mechanism allows clean separation of the enablement mechanism (inside the package scriptlets, by invoking +\fBsystemctl preset\fR) and enablement policy (centralized in the preset files), and lifts the configuration out of individual packages\&. Preset files may be written for specific distributions, for specific spins or for specific sites, in order to enforce different policies as needed\&. It is recommended to apply the policy encoded in preset files in package installation scriptlets\&. +.SH "SEE ALSO" +.PP +\fBsystemd\fR(1), +\fBsystemctl\fR(1), +\fBsystemd-delta\fR(1) +.PP +\fBdaemon\fR(7) +has a discussion of packaging scriptlets\&. +.PP +Fedora page introducing the use of presets: +\m[blue]\fBFeatures/PackagePresets\fR\m[]\&\s-2\u[1]\d\s+2\&. +.SH "NOTES" +.IP " 1." 4 +Features/PackagePresets +.RS 4 +\%https://fedoraproject.org/wiki/Features/PackagePresets +.RE |