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systemd.special


SYNOPSIS

       basic.target, bluetooth.target, ctrl-alt-del.target, cryptsetup.target,
       cryptsetup-pre.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, network-pre.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, -.slice, system.slice,
       user.slice, machine.slice


DESCRIPTION

       A few units are treated specially by systemd. They have special
       internal semantics and cannot be renamed.


SPECIAL SYSTEM UNITS

       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.

           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 found in
           /etc/fstab that have x-initrd.mount and not have noauto 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
           dependencies for their unit to this unit during installation. This
           is best configured via WantedBy=multi-user.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[1] 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
           do not 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.

           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.

           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).


SPECIAL SYSTEM UNITS FOR DEVICES

       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.


SPECIAL PASSIVE SYSTEM UNITS

       A number of special system targets are defined that can be used to
       properly order boot-up of optional services. These targets are

       cryptsetup-pre.target
           This passive target unit may be pulled in by services that want to
           run before any encrypted block device is set up. All encrypted
           block devices are set up after this target has been reached. Since
           the shutdown order is implicitly the reverse start-up order between
           units, this target is particularly useful to ensure that a service
           is shut down only after all encrypted block devices are fully
           stopped.

       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. It is hence
           useful when writing service files that require network access on
           shutdown, which should order themselves after this target, but not
           pull it in. Also see Running Services After the Network is up[1]
           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.

       network-pre.target
           This passive target unit may be pulled in by services that want to
           run before any network is set up, for example for the purpose of
           setting up a firewall. All network management software orders
           itself after this target, but does not pull it in.

       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. All services for which the availability of full host/network
           name resolution is essential should be ordered after this target,
           but not pull it in. 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. All services for which the availability of the full

       rpcbind.target
           The portmapper/rpcbind pulls in this target and orders itself
           before it, to indicate its availability. 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
           Services responsible for synchronizing the system clock from a
           remote source (such as NTP client implementations) should pull in
           this target and order themselves before it. All services where
           correct time is essential should be ordered after this unit, but
           not pull it in. 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.


SPECIAL SLICE UNITS

       There are four ".slice" units which form the basis of the hierarchy for
       assignment of resources for services, users, and virtual machines or
       containers.

       -.slice
           The root slice is the root of the hierarchy. It usually does not
           contain units directly, but may be used to set defaults for the
           whole tree.

       system.slice
           By default, all services services started by systemd are found in
           this slice.

       user.slice
           By default, all user processes started on behalf of the user are
           found in this slice.

       machine.slice
           By default, all virtual machines and containers registered with
           systemd-machined are found in this slice.


SEE ALSO

       systemd(1), systemd.unit(5), systemd.service(5), systemd.socket(5),
       systemd.target(5), systemd.slice(5), bootup(7), systemd-fstab-
       generator(8)


NOTES

        1. Running Services After the Network is up
           http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget

        2. Syslog Interface
           http://www.freedesktop.org/wiki/Software/systemd/syslog

        3. System Updates Specification
           http://freedesktop.org/wiki/Software/systemd/SystemUpdates
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