systemd.specialsystemdDeveloperLennartPoetteringlennart@poettering.netsystemd.special7systemd.specialSpecial systemd unitsbasic.target,
bluetooth.target,
ctrl-alt-del.target,
cryptsetup.target,
dbus.service,
dbus.socket,
default.target,
display-manager.service,
emergency.target,
exit.target,
final.target,
getty.target,
graphical.target,
halt.target,
hibernate.target,
hybrid-sleep.target,
kbrequest.target,
kexec.target,
local-fs.target,
local-fs-pre.target,
multi-user.target,
network.target,
nss-lookup.target,
nss-user-lookup.target,
poweroff.target,
printer.target,
reboot.target,
remote-fs.target,
remote-fs-pre.target,
rescue.target,
rpcbind.target,
runlevel2.target,
runlevel3.target,
runlevel4.target,
runlevel5.target,
shutdown.target,
sigpwr.target,
sleep.target,
smartcard.target,
sockets.target,
sound.target,
suspend.target,
swap.target,
sysinit.target,
syslog.socket,
syslog.target,
system-update.target,
time-sync.target,
umount.targetDescriptionA few units are treated specially by
systemd. They have special internal semantics and
cannot be renamed.Special System Unitsbasic.targetA special target unit
covering early boot-up.systemd automatically
adds dependencies of the types
Requires and After for this
target unit to all SysV
service units configured for
runlevel 1 to 5.Usually this should pull-in
all sockets, mount points,
swap devices and other basic
initialization necessary for
the general purpose
daemons. Most normal daemons
should have dependencies of
type After and Requires on
this unit.bluetooth.targetThis target is started
automatically as soon as a
bluetooth controller is
plugged in or becomes
available at boot.ctrl-alt-del.targetsystemd starts this
target whenever
Control+Alt+Del is pressed on
the console. Usually this
should be aliased (symlinked)
to
reboot.target.cryptsetup.targetA target that pulls in
setup services for all
encrypted block
devices.dbus.serviceA special unit for the
D-Bus system bus. As soon as
this service is fully started
up systemd will connect to it
and register its
service.dbus.socketA special unit for the
D-Bus system bus socket. All
units with
Type=dbus
automatically gain a
dependency on this
unit.default.targetThe default unit systemd
starts at bootup. Usually this
should be aliased (symlinked)
to
multi-user.target
or
graphical.target.The default unit systemd
starts at bootup can be
overridden with the
systemd.unit=
kernel command line option.display-manager.serviceThe display manager
service. Usually this should
be aliased (symlinked) to
gdm.service
or a similar display manager
service.emergency.targetA special target unit
that starts an emergency
shell on the main
console. This unit is supposed
to be used with the kernel
command line option
systemd.unit=
and has otherwise little use.
final.targetA special target unit
that is used during the
shutdown logic and may be used
to pull in late services after
all normal services are
already terminated and all
mounts unmounted.
getty.targetA special target unit
that pulls in all local TTY
getty instances.
graphical.targetA special target unit
for setting up a graphical
login screen. This pulls in
multi-user.target.Units that are needed
for graphical login shall add
Wants dependencies for their
unit to this unit (or
multi-user.target)
during installation.hibernate.targetA special target unit
for hibernating the
system. This pulls in
sleep.target.hybrid-sleep.targetA special target unit
for hibernating and suspending the
system at the same time. This pulls in
sleep.target.halt.targetA special target unit
for shutting down and halting the system.Applications wanting to
halt the system should start
this unit.kbrequest.targetsystemd starts this
target whenever Alt+ArrowUp is
pressed on the console. This
is a good candidate to be
aliased (symlinked) to
rescue.target.kexec.targetA special target unit
for shutting down and rebooting the system via kexec.Applications wanting to
reboot the system with kexec should start
this unit.local-fs.targetsystemd automatically
adds dependencies of type
After to all mount units that
refer to local mount points
for this target unit. In
addition, systemd adds
dependencies of type Wants to
this target unit for those
mounts listed in
/etc/fstab
that have the
and
mount options set.systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
$local_fs
facility.local-fs-pre.targetThis target unit is
automatically ordered before
all local mount points marked
with
(see above). It can be used to
execute certain units before
all local mounts.multi-user.targetA special target unit
for setting up a multi-user
system (non-graphical). This
is pulled in by
graphical.target.Units that are needed
for a multi-user system shall
add Wants dependencies to
this unit for their unit during
installation.network.targetsystemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
$network
facility.This unit is supposed to
indicate when the network is
"up", but it is only very
loosely defined what that is
supposed to mean. Also see Running
Services After the Network is
up for more
information.nss-lookup.targetA target that should be
used as synchronization point
for all host/network name
service lookups. Note that
this is independent of
user/group name lookups for
which
nss-user-lookup.target
should be used. systemd
automatically adds
dependencies of type After for
this target unit to all SysV
init script service units with
an LSB header referring to the
$named
facility.nss-user-lookup.targetA target that should be
used as synchronization point
for all user/group name
service lookups. Note that
this is independent of
host/network name lookups for
which
nss-lookup.target
should be used. poweroff.targetA special target unit
for shutting down and powering off the system.Applications wanting to
power off the system should start
this unit.runlevel0.target
is an alias for this target
unit, for compatibility with SysV.printer.targetThis target is started
automatically as soon as a
printer is plugged in or
becomes available at
boot.reboot.targetA special target unit
for shutting down and rebooting the system.Applications wanting to
reboot the system should start
this unit.runlevel6.target
is an alias for this target
unit, for compatibility with SysV.remote-fs.targetSimilar to
local-fs.target,
but for remote mount
points.systemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
$remote_fs
facility.remote-fs-pre.targetThis target unit is
automatically ordered before
all remote mount points marked
with
(see above). It can be used to
execute certain units before
all remote mounts.rescue.targetA special target unit
for setting up the base system
and a rescue shell.runlevel1.target
is an alias for this target
unit, for compatibility with SysV.rpcbind.targetsystemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
$portmap
facility.runlevel2.targetrunlevel3.targetrunlevel4.targetrunlevel5.targetThese are targets that
are called whenever the SysV
compatibility code asks for
runlevel 2, 3, 4, 5,
respectively. It is a good
idea to make this an alias for
(i.e. symlink to)
multi-user.target
(for runlevel 2) or
graphical.target
(the others).shutdown.targetA special target unit
that terminates the services
on system shutdown.Services that shall be
terminated on system shutdown
shall add Conflicts
dependencies to this unit for
their service unit, which is
implicitly done when
DefaultDependencies=yes
is set (the default).systemd automatically
adds dependencies of type
Conflicts to this target unit
for all SysV init script
service units that shall be
terminated in SysV runlevels 0
or 6.sigpwr.targetA special target that is
started when systemd receives
the SIGPWR process signal,
which is normally sent by the
kernel or UPS daemons when
power fails.sleep.targetA special target unit
that is pulled in by
suspend.target,
hibernate.target and hybrid-sleep.target
and may be used to hook units
into the sleep state
logic.smartcard.targetThis target is started
automatically as soon as a
smartcard controller is
plugged in or becomes
available at boot.sockets.targetA special target unit
that sets up all service
sockets.Services that can be
socket-activated shall add
Wants dependencies to this
unit for their socket unit
during installation.sound.targetThis target is started
automatically as soon as a
sound card is plugged in or
becomes available at
boot.suspend.targetA special target unit
for suspending the
system. This pulls in
sleep.target.swap.targetSimilar to
local-fs.target, but for swap
partitions and swap
files.sysinit.targetA special target unit
covering early boot-up scripts.systemd automatically
adds dependencies of the types
Wants and After for all
SysV service units configured
for runlevels that are not 0
to 6 to this target unit.
This covers the special
boot-up runlevels some
distributions have, such as S
or b.syslog.socketThe socket unit
syslog implementations should
listen on. All userspace log
messages will be made
available on this socket. For
more information about syslog
integration, please consult
the Syslog
Interface
document.syslog.targetsystemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
$syslog
facility.system-update.targetA special target unit
that is used for off-line
system updates.
systemd-system-update-generator8
will redirect the boot process
to this target if
/system-update
exists. For more information
see the System
Updates
Specification.time-sync.targetsystemd automatically
adds dependencies of type
After for this target unit to
all SysV init script service
units with an LSB header
referring to the
$time
facility.umount.targetA special target unit
that umounts all mount and
automount points on system
shutdown.Mounts that shall be
unmounted on system shutdown
shall add Conflicts
dependencies to this unit for
their mount unit, which is
implicitly done when
DefaultDependencies=yes
is set (the default).Special User UnitsWhen systemd runs as a user instance, the
following special units are available, which have
similar definitions as their system counterparts:
default.target,
shutdown.target,
sockets.targetIn addition the following special unit is
understood only when systemd runs as service instance:exit.targetA special service unit
for shutting down the
user service manager.Applications wanting to
terminate the user service
manager should start this
unit. If systemd receives
SIGTERM or SIGINT when running
as user service daemon it will
start this unit.Normally, this pulls in
shutdown.target
which in turn should be
conflicted by all units that
want to be shut down on
user service manager exit.See Alsosystemd1,
systemd.unit5,
systemd.service5,
systemd.socket5,
systemd.target5,
bootup7