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SYSTEMD-HALT.SERVICE(8)      systemd-halt.service      SYSTEMD-HALT.SERVICE(8)
NAME
       systemd-halt.service, systemd-poweroff.service, systemd-reboot.service,
       systemd-kexec.service, systemd-shutdown - System shutdown logic
SYNOPSIS
       systemd-halt.service
       systemd-poweroff.service
       systemd-reboot.service
       systemd-kexec.service
       /usr/lib/systemd/systemd-shutdown
       /usr/lib/systemd/system-shutdown/
DESCRIPTION
       systemd-halt.service is a system service that is pulled in by
       halt.target and is responsible for the actual system halt. Similarly,
       systemd-poweroff.service is pulled in by poweroff.target,
       systemd-reboot.service by reboot.target and systemd-kexec.service by
       kexec.target to execute the respective actions.
       When these services are run, they ensure that PID 1 is replaced by the
       /usr/lib/systemd/systemd-shutdown tool which is then responsible for
       the actual shutdown. Before shutting down, this binary will try to
       unmount all remaining file systems, disable all remaining swap devices,
       detach all remaining storage devices and kill all remaining processes.
       It is necessary to have this code in a separate binary because
       otherwise rebooting after an upgrade might be broken -- the running PID
       1 could still depend on libraries which are not available any more,
       thus keeping the file system busy, which then cannot be re-mounted
       read-only.
       Immediately before executing the actual system
       halt/poweroff/reboot/kexec systemd-shutdown will run all executables in
       /usr/lib/systemd/system-shutdown/ and pass one arguments to them:
       either "halt", "poweroff", "reboot" or "kexec", depending on the chosen
       action. All executables in this directory are executed in parallel, and
       execution of the action is not continued before all executables
       finished.
       Note that systemd-halt.service (and the related units) should never be
       executed directly. Instead, trigger system shutdown with a command such
       as "systemctl halt" or suchlike.
SEE ALSO
       systemd(1), systemctl(1), systemd.special(7), reboot(2), systemd-
       suspend.service(8), bootup(7)
systemd 239                                            SYSTEMD-HALT.SERVICE(8)