systemd.special — special systemd units
basic.target,
                ctrl-alt-del.target,
                dbus.service,
                default.target,
                display-manager.service,
                emergency.target,
                exit.service,
                graphical.target,
                halt.target,
                kbrequest.target,
                local-fs.target,
                local-fs-pre.target,
                mail-transfer-agent.target,
                multi-user.target,
                network.target,
                nss-lookup.target,
                poweroff.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,
                sockets.target,
                swap.target,
                sysinit.target,
                syslog.target,
                systemd-initctl.service,
                systemd-initctl.socket,
                systemd-stdout-syslog-bridge.service,
                systemd-stdout-syslog-bridge.socket,
                time-sync.target,
                umount.target
A few units are treated specially by systemd. They have special internal semantics and cannot be renamed.
basic.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.
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.
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.
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
                                        xdm.service
                                        or a similar display manager
                                        service.
systemd automatically
                                        adds dependencies of type
                                        After for this target unit to
                                        all SysV init script service
                                        units with a LSB header
                                        referring to the
                                        $x-display-manager
                                        facility, for compatibility
                                        with Debian.
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.
                                        
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.
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.
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
                                        auto and
                                        comment=systemd.mount
                                        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 auto
                                        (see above). It can be used to
                                        execute certain units before
                                        all local mounts.
mail-transfer-agent.targetThe mail transfer agent (MTA) service. Usually this should pull-in all units necessary for sending/receiving mails on the local host.
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
                                        $mail-transfer-agent
                                        or
                                        $mail-transport-agent
                                        facilities, for compatibility
                                        with Debian.
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.
nss-lookup.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
                                        $named
                                        facility.
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.
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 auto
                                        (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
                                        $rpcbind
                                        facility.
runlevel2.targetThis is a target that is
                                        called whenever the SysV
                                        compatibility code asks for
                                        runlevel 2. It is a good idea
                                        to make this an alias for
                                        (i.e. symlink to)
                                        multi-user.target.
runlevel3.targetThis is a target that is
                                        called whenever the SysV
                                        compatibility code asks for
                                        runlevel 3. It is a good idea
                                        to make this an alias for
                                        (i.e. symlink to)
                                        multi-user.target
                                        or
                                        graphical.target.
runlevel4.targetThis is a target that is
                                        called whenever the SysV
                                        compatibility code asks for
                                        runlevel 4. It is a good idea
                                        to make this an alias for
                                        (i.e. symlink to)
                                        multi-user.target
                                        or
                                        graphical.target.
runlevel5.targetThis is a target that is
                                        called whenever the SysV
                                        compatibility code asks for
                                        runlevel 5. It is a good idea
                                        to make this an alias for
                                        (i.e. symlink to)
                                        multi-user.target
                                        or
                                        graphical.target.
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.
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.
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.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.
systemd-initctl.serviceThis provides compatibility with the SysV /dev/initctl file system FIFO for communication with the init system.
This is a
                                        socket-activated service, see
                                        system-initctl.socket.
systemd-initctl.socketSocket activation unit
                                        for
                                        system-initctl.service.
systemd-stdout-syslog-bridge.serviceThis is internally used by systemd to provide syslog logging to the processes it maintains.
This is a
                                        socket-activated service, see
                                        system-stdout-syslog-bridge.socket.
systemd-stdout-syslog-bridge.socketSocket activation unit
                                        for
                                        system-stdout-syslog-bridge.service. systemd
                                        will automatically add
                                        dependencies of types Requires
                                        and After to all units that
                                        have been configured for
                                        stdout or stderr to be
                                        connected to syslog or the
                                        kernel log buffer.
systemd-shutdownd.serviceThis is internally used by shutdown(8) to implement delayed shutdowns.
This is a
                                        socket-activated service, see
                                        system-shutdownd.socket.
systemd-shutdownd.socketSocket activation unit
                                        for
                                        system-shutdownd.service.
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).
When systemd runs as a user instance, the
                following special units are available, which have
                similar definitions as their system counterparts:
                default.target,
                local-fs.target,
                remote-fs.target,
                shutdown.target,
                sockets.target,
                swap.target.
In addition the following special unit is understood only when systemd runs as service instance:
exit.serviceA 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.