name : dracut-shutdown.service.8.asc 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: * systemd switches to the shutdown.target * systemd starts /lib/systemd/system/shutdown.target.wants/dracut-shutdown.service * dracut-shutdown.service executes /usr/lib/dracut/dracut-initramfs-restore which unpacks the initramfs to /run/initramfs * systemd finishes shutdown.target * 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 umount 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)