add dracut-shutdown.service.8.asc manpage

Makefile

@@ -28,6 +28,7 @@ man8pages = dracut.8 \
             modules.d/98systemd/dracut-cmdline.service.8 \
             modules.d/98systemd/dracut-initqueue.service.8 \
             modules.d/98systemd/dracut-mount.service.8 \
+            modules.d/98systemd/dracut-shutdown.service.8 \
             modules.d/98systemd/dracut-pre-mount.service.8 \
             modules.d/98systemd/dracut-pre-pivot.service.8 \
             modules.d/98systemd/dracut-pre-trigger.service.8 \

modules.d/98systemd/dracut-shutdown.service

@@ -7,6 +7,7 @@
 
 [Unit]
 Description=Restore /run/initramfs
+Documentation=man:dracut-shutdown.service(8)
 After=getty@tty1.service prefdm.service
 Before=systemd-reboot.service shutdown.target
 DefaultDependencies=no

modules.d/98systemd/dracut-shutdown.service.8.asc

@@ -0,0 +1,50 @@
+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 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 Hoyer
+
+SEE ALSO
+--------
+*dracut*(8)