SYSTEMD-HALT.SERVICE(8) systemd-halt.service SYSTEMD-HALT.SERVICE(8)
systemd-halt.service, systemd-poweroff.service, systemd- reboot.service, systemd-kexec.service, systemd-shutdown - System shutdown logic
systemd-halt.service systemd-poweroff.service systemd-reboot.service systemd-kexec.service /usr/lib/systemd/systemd-shutdown /usr/lib/systemd/system-shutdown/
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.
systemd(1), systemctl(1), systemd.special(7), reboot(2), systemd-suspend.service(8), bootup(7)
This page is part of the systemd (systemd system and service manager) project. Information about the project can be found at ⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug report for this manual page, see ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This page was obtained from the project's upstream Git repository ⟨https://github.com/systemd/systemd.git⟩ on 2021-06-20. (At that time, the date of the most recent commit that was found in the repository was 2021-06-19.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to email@example.com systemd 249 SYSTEMD-HALT.SERVICE(8)
Pages that refer to this page: bootup(7), systemd.directives(7), systemd.index(7), systemd-suspend.service(8)