x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SYSTEMD.TARGET(5) systemd.target SYSTEMD.TARGET(5)
NAME
systemd.target - Target unit configuration
SYNOPSIS
target.target
DESCRIPTION
A unit configuration file whose name ends in ".target" encodes
information about a target unit of systemd. Target units are used to
group units and to set synchronization points for ordering dependencies
with other unit files.
This unit type has no specific options. See systemd.unit(5) for the
common options of all unit configuration files. The common
configuration items are configured in the generic [Unit] and [Install]
sections. A separate [Target] section does not exist, since no
target-specific options may be configured.
Target units do not offer any additional functionality on top of the
generic functionality provided by units. They merely group units,
allowing a single target name to be used in Wants= and Requires=
settings to establish a dependency on a set of units defined by the
target, and in Before= and After= settings to establish ordering.
Targets establish standardized names for synchronization points during
boot and shutdown. Importantly, see systemd.special(7) for examples and
descriptions of standard systemd targets.
Target units provide a more flexible replacement for SysV runlevels in
the classic SysV init system. For compatibility reasons special target
units such as runlevel3.target exist which are used by the SysV
runlevel compatibility code in systemd, see systemd.special(7) for
details.
Note that a target unit file must not be empty, lest it be considered a
masked unit. It is recommended to provide a [Unit] section which
includes informative Description= and Documentation= options.
AUTOMATIC DEPENDENCIES
Implicit Dependencies
There are no implicit dependencies for target units.
Default Dependencies
The following dependencies are added unless DefaultDependencies=no is
set:
o Target units will automatically complement all configured
dependencies of type Wants= or Requires= with dependencies of type
After= unless DefaultDependencies=no is set in the specified units.
Note that the reverse is not true. For example, defining
Wants=that.target in some.service will not automatically add the
After=that.target ordering dependency for some.service. Instead,
some.service should use the primary synchronization function of
target type units, by setting a specific After=that.target or
Before=that.target ordering dependency in its .service unit file.
o Target units automatically gain Conflicts= and Before= dependencies
against shutdown.target.
OPTIONS
Target unit files may include [Unit] and [Install] sections, which are
described in systemd.unit(5). No options specific to this file type are
supported.
EXAMPLE
Example 1. Simple standalone target
# emergency-net.target
[Unit]
Description=Emergency Mode with Networking
Requires=emergency.target systemd-networkd.service
After=emergency.target systemd-networkd.service
AllowIsolate=yes
When adding dependencies to other units, it's important to check if
they set DefaultDependencies=. Service units, unless they set
DefaultDependencies=no, automatically get a dependency on
sysinit.target. In this case, both emergency.target and
systemd-networkd.service have DefaultDependencies=no, so they are
suitable for use in this target, and do not pull in sysinit.target.
You can now switch into this emergency mode by running systemctl
isolate emergency-net.target or by passing the option
systemd.unit=emergency-net.target on the kernel command line.
Other units can have WantedBy=emergency-net.target in the [Install]
section. After they are enabled using systemctl enable, they will be
started before emergency-net.target is started. It is also possible to
add arbitrary units as dependencies of emergency.target without
modifying them by using systemctl add-wants.
SEE ALSO
systemd(1), systemctl(1), systemd.unit(5), systemd.special(7),
systemd.directives(7)
systemd 254 SYSTEMD.TARGET(5)
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