My root node is LUKS encrypted, and it uses a key file, instead of user input password to unlock it.
I know in Grub2, I can use
insmod cryptodisk insmod luks cryptomount -u <uuid>
But I have no idea how to use a key file to unlock the disk.
change (hd0,1) (if necessary)and put the mounting point of the keyfile file system, sda or whatsoever...