All done! You are almost ready to start wolfing.
Reboot your boxes. Did they all come up? Can you ping the head node from each box? Can you ping each node from the head node? Can you ssh? Don't worry about doing ssh as root; only as wolf. Also only worry about ssh from the head to the slave, not the other way around.
If you are logged in as wolf, and ssh to a box, does it go automatically, without prompting for password?
After the node boots up, log in as wolf, and say "mount". Does it show wolf00:/mnt/wolf mounted? On the head node, copy a file into /mnt/wolf. Can you read and write that file from the slave node?
This is really not required; it is merely convenient to have a common directory reside on the head node. With a common shared directory, you can easily use scp to copy files between boxes. Sterling states in his book, on page 119, a single NFS server causes a serious obstacle to scaling up to large numbers of nodes. I learned this when I went from a small number of boxes up to a large number.