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DRACUT-SHUTDOWN.S(8) | dracut | DRACUT-SHUTDOWN.S(8) |
NAME¶
dracut-shutdown.service - unpack the initramfs to /run/initramfsSYNOPSIS¶
dracut-shutdown.serviceDESCRIPTION¶
This service unpacks the initramfs image to /run/initramfs. systemd pivots into /run/initramfs at shutdown, so the root filesytem 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
AUTHORS¶
Harald HoyerSEE ALSO¶
dracut(8)01/24/2017 | dracut |