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systemd-poweroff.service(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COLOPHON 

SYSTEMD-P...F.SERVICE(8) systemd-poweroff.serviceSYSTEMD-P...F.SERVICE(8)

NAME         top

       systemd-poweroff.service, systemd-halt.service, systemd-
       reboot.service, systemd-kexec.service, systemd-shutdown - System
       shutdown logic

SYNOPSIS         top

       systemd-poweroff.service

       systemd-halt.service

       systemd-reboot.service

       systemd-kexec.service

       /usr/lib/systemd/systemd-shutdown

       /usr/lib/systemd/system-shutdown/

DESCRIPTION         top

       systemd-poweroff.service is a system service that is pulled in by
       poweroff.target and is responsible for the actual system power-off
       operation. Similarly, systemd-halt.service is pulled in by
       halt.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 binary which is then
       responsible for the actual shutdown. Before shutting down, this
       binary will try to unmount all remaining file systems (or at least
       remount them read-only), 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.

       Shortly before executing the actual system
       power-off/halt/reboot/kexec, systemd-shutdown will run all
       executables in /usr/lib/systemd/system-shutdown/ and pass one
       arguments to them: either "poweroff", "halt", "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. (A safety timeout
       of 90s is applied however.) Note that these executables are run
       after all services have been shut down, and after most mounts have
       been unmounted (the root file system as well as /run/ and various
       API file systems are still around though). This means any programs
       dropped into this directory must be prepared to run in such a
       limited execution environment and not rely on external services or
       hierarchies such as /var/ to be around (or writable).

       Note that systemd-poweroff.service (and the related units) should
       never be executed directly. Instead, trigger system shutdown with
       a command such as "systemctl poweroff".

       Another form of shutdown is provided by the
       systemd-soft-reboot.service(8) functionality. It reboots only the
       OS userspace, leaving the kernel, firmware, and hardware as it is.

SEE ALSO         top

       systemd(1), systemctl(1), systemd.special(7), reboot(2),
       systemd-suspend.service(8), systemd-soft-reboot.service(8),
       bootup(7)

COLOPHON         top

       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 2025-02-02.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2025-02-02.)  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
       man-pages@man7.org

systemd 258~devel                                SYSTEMD-P...F.SERVICE(8)

Pages that refer to this page: bootup(7),  systemd.directives(7),  systemd.index(7),  systemd.special(7),  systemd-soft-reboot.service(8),  systemd-suspend.service(8)

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