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