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, which is used for grouping
units and as well-known synchronization points during start-up.
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 exist merely to group
units via dependencies (useful as boot targets), and to establish
standardized names for synchronization points used in dependencies
between units. Among other things, target units are a more flexible
replacement for SysV runlevels in the classic SysV init system. (And
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).
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 Wants= or Requires= must be defined in the target unit
itself -- if you for example define Wants=some.target in
some.service, the automatic ordering will not be added.
o Target units automatically gain Conflicts= and Before= dependencies
against shutdown.target.
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 245 SYSTEMD.TARGET(5)