OK, at this point what we did was make a new user on each and every node just for us clustering types! I login to each node (PC) as root and use adduser/userdel command lines. This user has the same userid, say "cluster," and passwd on every node.
Then we set up ssh public key authentication for each of these new users as detailed here:
With this setup, you need only login as "cluster" on one linuxbox and you can ssh into any other linuxbox with the same userid/passwd and you don't have to specify either the userid or the passwd! Its like you are logged into all 25 PCs at once! This makes it easy to send jobs from the PC you are logged into (the master node) and recieve results from all the other nodes (the worker nodes) whenever we need to scatter/gather jobs.
Until next time,