systemd.special — Special systemd units
basic.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,
                initrd-fs.target,
                kbrequest.target,
                kexec.target,
                local-fs.target,
                local-fs-pre.target,
                multi-user.target,
                network.target,
                network-online.target,
                nss-lookup.target,
                nss-user-lookup.target,
                paths.target,
                poweroff.target,
                printer.target,
                reboot.target,
                remote-fs.target,
                remote-fs-pre.target,
                rescue.target,
                initrd-root-fs.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,
                system-update.target,
                time-sync.target,
                timers.target,
                umount.target
A few units are treated specially by systemd. They have special internal semantics and cannot be renamed.
basic.target¶A special target unit covering basic boot-up.
systemd automatically
                                        adds dependencies of the types
                                        Requires=
                                        and After=
                                        for this target unit to all
                                        services (except for those
                                        with
                                        DefaultDependencies=no).
Usually this should pull-in all mount points, swap devices, sockets, timers, and path units and other basic initialization necessary for general purpose daemons.
ctrl-alt-del.target¶systemd starts this
                                        target whenever
                                        Control+Alt+Del is pressed on
                                        the console. Usually this
                                        should be aliased (symlinked)
                                        to
                                        reboot.target.
cryptsetup.target¶A target that pulls in setup services for all encrypted block devices.
dbus.service¶A special unit for the D-Bus bus daemon. As soon as this service is fully started up systemd will connect to it and register its service.
dbus.socket¶A special unit for the
                                        D-Bus system bus socket. All
                                        units with
                                        Type=dbus
                                        automatically gain a
                                        dependency on this
                                        unit.
default.target¶The 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.service¶The display manager
                                        service. Usually this should
                                        be aliased (symlinked) to
                                        gdm.service
                                        or a similar display manager
                                        service.
emergency.target¶A 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.target¶A 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.target¶A special target unit
                                        that pulls in statically
                                        configured local TTY
                                        getty
                                        instances.
                                        
graphical.target¶A special target unit
                                        for setting up a graphical
                                        login screen. This pulls in
                                        multi-user.target.
Units that are needed
                                        for graphical logins shall add
                                        Wants=
                                        dependencies for their unit to
                                        this unit (or
                                        multi-user.target)
                                        during installation. This is
                                        best configured via
                                        WantedBy=graphical.target
                                        in the unit's
                                        [Install]
                                        section.
hibernate.target¶A special target unit
                                        for hibernating the
                                        system. This pulls in
                                        sleep.target.
hybrid-sleep.target¶A special target unit
                                        for hibernating and suspending the
                                        system at the same time. This pulls in
                                        sleep.target.
halt.target¶A special target unit
                                        for shutting down and halting
                                        the system. Note that this
                                        target is distinct from
                                        poweroff.target
                                        in that it generally really
                                        just halts the system rather
                                        than powering it down.
Applications wanting to halt the system should start this unit.
initrd-fs.target¶systemd-fstab-generator(3)
                                        automatically adds
                                        dependencies of type
                                        Before= to
                                        sysroot-usr.mount
                                        and all mount points fround in
                                        /etc/fstab
                                        that have the
                                        auto and
                                        x-initrd.mount
                                        mount options set.
                                        
kbrequest.target¶systemd starts this
                                        target whenever Alt+ArrowUp is
                                        pressed on the console. This
                                        is a good candidate to be
                                        aliased (symlinked) to
                                        rescue.target.
kexec.target¶A 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.target¶systemd-fstab-generator(3)
                                        automatically adds
                                        dependencies of type
                                        Before= to
                                        all mount units that refer to
                                        local mount points for this
                                        target unit. In addition, it
                                        adds dependencies of type
                                        Wants= to
                                        this target unit for those
                                        mounts listed in
                                        /etc/fstab
                                        that have the
                                        auto mount
                                        option set.
multi-user.target¶A 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 for their unit to
                                        this unit during
                                        installation. This is best
                                        configured via
                                        WantedBy=multi-uer.target
                                        in the unit's
                                        [Install]
                                        section.
network-online.target¶Units that strictly
                                        require a configured network
                                        connection should pull in
                                        network-online.target
                                        (via a
                                        Wants= type
                                        dependency) and order
                                        themselves after it. This
                                        target unit is intended to
                                        pull in a service that delays
                                        further execution until the
                                        network is sufficiently set
                                        up. What precisely this
                                        requires is left to the
                                        implementation of the network
                                        managing service.
Note the distinction
                                        between this unit and
                                        network.target. This
                                        unit is an active unit
                                        (i.e. pulled in by the
                                        consumer rather than the
                                        provider of this
                                        functionality) and pulls in a
                                        service which possibly adds
                                        substantial delays to further
                                        execution. In contrast,
                                        network.target
                                        is a passive unit (i.e. pulled
                                        in by the provider of the
                                        functionality, rather than the
                                        consumer) that usually does
                                        not delay execution
                                        much. Usually,
                                        network.target
                                        is part of the boot of most
                                        systems, while
                                        network-online.target
                                        is not, except when at least
                                        one unit requires it. Also see
                                        Running
                                        Services After the Network is
                                        up for more
                                        information.
All mount units for remote network file systems automatically pull in this unit, and order themselves after it. Note that networking daemons that simply provide functionality to other hosts generally don't need to pull this in.
paths.target¶A special target unit that sets up all path units (see systemd.path(5) for details) that shall be active after boot.
It is recommended that
                                        path units installed by
                                        applications get pulled in via
                                        Wants=
                                        dependencies from this
                                        unit. This is best configured
                                        via a
                                        WantedBy=paths.target
                                        in the path unit's
                                        [Install]
                                        section.
poweroff.target¶A 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.target¶A 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.target¶Similar 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.
rescue.target¶A 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.
initrd-root-fs.target¶systemd-fstab-generator(3)
                                        automatically adds
                                        dependencies of type
                                        Before= to
                                        the
                                        sysroot.mount
                                        unit, which is generated from
                                        the kernel command line.
                                        
runlevel2.target, runlevel3.target, runlevel4.target, runlevel5.target¶These 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.target¶A 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).
sigpwr.target¶A 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.target¶A 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.
sockets.target¶A special target unit that sets up all socket units.(see systemd.socket(5) for details) that shall be active after boot.
Services that can be
                                        socket-activated shall add
                                        Wants=
                                        dependencies to this unit for
                                        their socket unit during
                                        installation. This is best
                                        configured via a
                                        WantedBy=sockets.target
                                        in the socket unit's
                                        [Install]
                                        section.
suspend.target¶A special target unit
                                        for suspending the
                                        system. This pulls in
                                        sleep.target.
swap.target¶Similar to
                                        local-fs.target, but for swap
                                        partitions and swap
                                        files.
sysinit.target¶A special target unit covering early boot-up scripts.
syslog.socket¶The 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.
system-update.target¶A special target unit
                                        that is used for off-line
                                        system updates.
                                        systemd-system-update-generator(8)
                                        will redirect the boot process
                                        to this target if
                                        /system-update
                                        exists. For more information
                                        see the System
                                        Updates
                                        Specification.
timers.target¶A special target unit that sets up all timer units (see systemd.timer(5) for details) that shall be active after boot.
It is recommended that
                                        timer units installed by
                                        applications get pulled in via
                                        Wants=
                                        dependencies from this
                                        unit. This is best configured
                                        via
                                        WantedBy=timers.target
                                        in the timer unit's
                                        [Install]
                                        section.
umount.target¶A 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).
Some target units are automatically pulled in as devices of certain kinds show up in the system. These may be used to automatically activate various services based on the specific type of the available hardware.
bluetooth.target¶This target is started automatically as soon as a Bluetooth controller is plugged in or becomes available at boot.
This may be used to pull in Bluetooth management daemons dynamically when Bluetooth hardware is found.
printer.target¶This target is started automatically as soon as a printer is plugged in or becomes available at boot.
This may be used to pull in printer management daemons dynamically when printer hardware is found.
smartcard.target¶This target is started automatically as soon as a smartcard controller is plugged in or becomes available at boot.
This may be used to pull in smartcard management daemons dynamically when smartcard hardware is found.
sound.target¶This target is started automatically as soon as a sound card is plugged in or becomes available at boot.
This may be used to pull in audio management daemons dynamically when audio hardware is found.
A number of special system targets are defined
                that can be used to properly order boot-up of optional
                services. These targets are generally not part of the
                initial boot transaction, unless they are explicitly
                pulled in by one of the implementing services. Note
                specifically, that these passive
                target units are generally not pulled in by the
                consumer of a service, but by the provider of the
                service. This means: a consuming service should order
                itself after these targets (as appropriate), but not
                pull it in. A providing service should order itself
                before these targets (as appropriate) and pull it in
                (via a Wants= type
                dependency).
Note that these passive units cannot be started
                manually, i.e. systemctl start
                time-sync.target will fail with an
                error. They can only be pulled in by dependency. This
                is enforced since they exist for ordering purposes
                only and thus are not useful as only unit within a
                transaction.
local-fs-pre.target¶This 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.
network.target¶This unit is supposed to
                                        indicate when network
                                        functionality is available,
                                        but it is only very weakly
                                        defined what that is supposed
                                        to mean, with one exception:
                                        at shutdown, a unit that is
                                        ordered after
                                        network.target
                                        will be stopped before the
                                        network -- to whatever level
                                        it might be set up then -- is
                                        shut down. Also see Running
                                        Services After the Network is
                                        up for more
                                        information. Also see
                                        network-online.target
                                        described above.
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
                                        $network
                                        facility.
nss-lookup.target¶A 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.target¶A 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. 
remote-fs-pre.target¶This target unit is
                                        automatically ordered before
                                        all remote mount point units
                                        (see above). It can be used to
                                        run certain units before the
                                        remote mounts are
                                        established. Note that this
                                        unit is generally not part of
                                        the initial transaction,
                                        unless the unit that wants to
                                        be ordered before all remote
                                        mounts pulls it in via a
                                        Wants= type
                                        dependency. If the unit wants
                                        to be pulled in by the first
                                        remote mount showing up it
                                        should use
                                        network-online.target
                                        (see above).
Again, this target unit is not suitable for pulling in other units, it is only useful for ordering.
rpcbind.target¶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
                                        $portmap
                                        facility.
time-sync.target¶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
                                        $time
                                        facility.
When 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.target,
                timers.target,
                paths.target,
                bluetooth.target,
                printer.target,
                smartcard.target,
                sound.target.
In addition the following special unit is understood only when systemd runs as service instance:
exit.target¶A 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.