dracut-shutdown.service(8) [centos man page]

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

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:

       o   systemd switches to the shutdown.target

       o   systemd starts /lib/systemd/system/shutdown.target.wants/dracut-shutdown.service

       o   dracut-shutdown.service executes /usr/lib/dracut/dracut-initramfs-restore which unpacks the initramfs to /run/initramfs

       o   systemd finishes shutdown.target

       o   systemd kills all processes

       o   systemd tries to unmount everything and mounts the remaining read-only

       o   systemd checks, if there is a /run/initramfs/shutdown executable

       o   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.

       o   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)

dracut								    09/12/2013						      DRACUT-SHUTDOWN.S(8)

DRACUT.BOOTUP(7)						      dracut							  DRACUT.BOOTUP(7)

NAME

       dracut.bootup - boot ordering in the initramfs

DESCRIPTION

       This flow chart illustrates the ordering of the services, if systemd is used in the dracut initramfs.

					       systemd-journal.socket
							  |
							  v
					       dracut-cmdline.service
							  |
							  v
					       dracut-pre-udev.service
							  |
							  v
						systemd-udevd.service
							  |
							  v
	   local-fs-pre.target		      dracut-pre-trigger.service
		    |					  |
		    v					  v
	    (various mounts)  (various swap  systemd-udev-trigger.service
		    |		devices...)		  |		(various low-level   (various low-level
		    |		    |			  |		services: seed,       API VFS mounts:
		    v		    v			  v		tmpfiles, random     mqueue, configfs,
	     local-fs.target   swap.target     dracut-initqueue.service    sysctl, ...)        debugfs, ...)
		    |		    |			  |		       |		    |
		    \_______________|____________________ | ___________________|____________________/
							 |/
							  v
						   sysinit.target
							  |
					_________________/|\___________________
				       /		  |		       
				       |		  |		       |
				       v		  |		       v
				   (various		  |		 rescue.service
				  sockets...)		  |		       |
				       |		  |		       v
				       v		  |		 rescue.target
				sockets.target		  |
				       |		  |
				       \_________________ |				    emergency.service
							 |					    |
							  v					    v
						    basic.target			     emergency.target
							  |
				   ______________________/|
				  /			  |
				  |			  v
				  |	       dracut-pre-mount.service
				  |			  |
				  |			  v
				  |		     sysroot.mount
				  |			  |
				  |			  v
				  |		initrd-root-fs.target
		      (custom initrd services)		  |
				  |			  v
				  |		dracut-mount.service
				  |			  |
				  |			  v
				  |	       initrd-parse-etc.service
				  |			  |
				  |			  v
				  |	       (sysroot-usr.mount and
				  |		various mounts marked
				  |		  with fstab option
				  |		   x-initrd.mount)
				  |			  |
				  |			  v
				  |		   initrd-fs.target
				  \______________________ |
							 |
							  v
						     initrd.target
							  |
							  v
					       dracut-pre-pivot.service
							  |
							  v
						initrd-cleanup.service
						     isolates to
					       initrd-switch-root.target
							  |
							  v
				   ______________________/|
				  /			  |
				  |	   initrd-udevadm-cleanup-db.service
				  |			  |
		      (custom initrd services)		  |
				  |			  |
				  \______________________ |
							 |
							  v
					      initrd-switch-root.target
							  |
							  v
					      initrd-switch-root.service
							  |
							  v
						     switch-root

AUTHOR

       Harald Hoyer

SEE ALSO

       dracut(8) bootup(7)

dracut								    06/12/2014							  DRACUT.BOOTUP(7)