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

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COLOPHON 

SYSTEMD-....SERVICE(8)  systemd-poweroff.service  SYSTEMD-....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 tool 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. 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 2024-06-14.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2024-06-13.)  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 257~devel                                 SYSTEMD-....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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