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DRACUT-SHUTDOWN.SERVICE(8) =========================== :doctype: manpage :man source: dracut :man manual: dracut NAME ---- dracut-shutdown.service - unpack the initramfs to /run/initramfs SYNOPSIS -------- dracut-shutdown.service DESCRIPTION ----------- This service unpacks the initramfs image to /run/initramfs. systemd pivots into /run/initramfs at shutdown, so the root filesystem can be safely unmounted. The following steps are executed during a shutdown: * The system starts to shut down * ``$prefix/lib/systemd/system/sysinit.target.wants/dracut-shutdown.service`` gets its ``ExecStop`` target triggered. * ``dracut-shutdown.service`` executes ``/usr/lib/dracut/dracut-initramfs-restore`` which unpacks the initramfs to ``/run/initramfs`` * systemd kills all processes * systemd tries to unmount everything and mounts the remaining read-only * systemd checks if there is a ``/run/initramfs/shutdown`` executable * if yes, it does a pivot_root to ``/run/initramfs`` and executes ``./shutdown``. The old root is then mounted on ``/oldroot``. ``/usr/lib/dracut/modules.d/99shutdown/shutdown.sh`` is the shutdown executable. * shutdown will try to unmount every ``/oldroot`` mount and calls the various shutdown hooks from the dracut modules This ensures, that all devices are disassembled and unmounted cleanly. To debug the shutdown process, you can get a shell in the shutdown procedure by injecting "rd.break=pre-shutdown rd.shell" or "rd.break=shutdown rd.shell". ---- # mkdir -p /run/initramfs/etc/cmdline.d # echo "rd.break=pre-shutdown rd.shell" > /run/initramfs/etc/cmdline.d/debug.conf # touch /run/initramfs/.need_shutdown ---- In case the unpack of the initramfs fails, dracut-shutdown-onfailure.service executes to make sure switch root doesn't happen, since it would result in switching to an incomplete initramfs. AUTHORS ------- Harald Hoyer SEE ALSO -------- *dracut*(8)
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