Comment 4 for bug 1155403

Are you sure you booted from the cd, not the hd? I'm using the raring-server-amd64.iso and it doesn't work. It has also been reported in debian:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=+689528

Looking at the output of udevadm info --query --path=/dev/vda it is pretty obvious what the problem is: it looks like a hard disk, not a cdrom, and cdrom-detect is looking for a cdrom.