Nothing is free, at home want to open a virtual machine to play, did not expect to forget the password. Ashamed ah! I remember to restart shutdown, then RO behind the data and then add rd.break.
And shift a long time, almost to the virtual machine ruined!
Eventually found, virtual and physical machines there are differences.
In the above physical machine directly engage rd.break
On the virtual machine you have to add about console = tty0
Otherwise, you run ctrl + x to enter an emergency mode, it will error, it does not have permission to make the mount has been stuck there.
Will enter swich mode after the set up and execution
mount -o remount,rw /sysroot
Execute the command: mount -o remount, rw / sysroot
Then after chroot / directory under sysroot
Perform change password
Change Password Enter password root
. . . . . . enter password
Or directly passwd
touch /.autorelabel
exit