Booting from cd and no /dev/md devices?
First, correct kernel modules are needed.
modprobe raid1
If configuration uses different raid, then a different raid module should be loaded. Be it a raid 0,5,6 or whatever.
Devices can be made then
mknod /dev/md0 b 9 0
mknod /dev/md1 b 9 1
and so on. As many of them as needed.
From this point on door is open for mdadm create,assemble or whatever is needed.
Creating a device goes like this:
mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda2 /dev/sdc2
