1DRACUT-SHUTDOWN.S(8)                dracut                DRACUT-SHUTDOWN.S(8)
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NAME

6       dracut-shutdown.service - unpack the initramfs to /run/initramfs
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SYNOPSIS

9       dracut-shutdown.service
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DESCRIPTION

12       This service unpacks the initramfs image to /run/initramfs. systemd
13       pivots into /run/initramfs at shutdown, so the root filesystem can be
14       safely unmounted.
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16       The following steps are executed during a shutdown:
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18       •   systemd switches to the shutdown.target
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20       •   systemd starts
21           /lib/systemd/system/shutdown.target.wants/dracut-shutdown.service
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23       •   dracut-shutdown.service executes
24           /usr/lib/dracut/dracut-initramfs-restore which unpacks the
25           initramfs to /run/initramfs
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27       •   systemd finishes shutdown.target
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29       •   systemd kills all processes
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31       •   systemd tries to unmount everything and mounts the remaining
32           read-only
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34       •   systemd checks, if there is a /run/initramfs/shutdown executable
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36       •   if yes, it does a pivot_root to /run/initramfs and executes
37           ./shutdown. The old root is then mounted on /oldroot.
38           /usr/lib/dracut/modules.d/99shutdown/shutdown.sh is the shutdown
39           executable.
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41       •   shutdown will try to umount every /oldroot mount and calls the
42           various shutdown hooks from the dracut modules
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44       This ensures, that all devices are disassembled and unmounted cleanly.
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46       To debug the shutdown process, you can get a shell in the shutdown
47       procedure by injecting "rd.break=pre-shutdown rd.shell" or
48       "rd.break=shutdown rd.shell".
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50           # mkdir -p /run/initramfs/etc/cmdline.d
51           # echo "rd.break=pre-shutdown rd.shell" > /run/initramfs/etc/cmdline.d/debug.conf
52           # touch /run/initramfs/.need_shutdown
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54       In case the unpack of the initramfs fails,
55       dracut-shutdown-onfailure.service executes to make sure switch root
56       doesn’t happen, since it would result in switching to an incomplete
57       initramfs.
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AUTHORS

60       Harald Hoyer
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SEE ALSO

63       dracut(8)
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67dracut                            02/18/2022              DRACUT-SHUTDOWN.S(8)
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