On 17.08.2012, Mateusz Marzantowicz wrote:
3) Modify /etc/default/grub by changing GRUB_CMDLINE_LINUX:
rd.luks.key=<filename>:<device>
I agree that the available documentation is horrible. However,
I think you should mention here that <device> should be specified with
the UUID prefix, e.g.
rd.luks.key=/mykeyfile:UUID=xxxxxxxx
4) Recreate /boot/grub2/grub.cfg file.
5) Reboot and see how your partition is unlocked without passphrase.
As far as I remember last time I looked into dracut and udev sources,
a keyfile found here is probed against all available devices, so you
should be able to unlock several encrypted partitions with just one
keyfile, just as it works with a conventional passphrase.