Setting Up (and Using) SSH

In order to use the cluster, you must log in using SSH. Telnet has been disabled for security reasons. In addition, to effectively use the cluster, you must be able to run commands on other machines within the cluster without specifying a password. This is accomplished by generating an SSH key pair without a passphrase, and correctly configuring authorization.

To generate your key pair, use the ssh-keygen command:

bash$ ssh-keygen -d
Generating DSA parameter and key.
Enter file in which to save the key (/home/beowulf/joe/.ssh/id_dsa): 
Created directory '/home/beowulf/joe/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/beowulf/joe/.ssh/id_dsa.
Your public key has been saved in /home/beowulf/joe/.ssh/id_dsa.pub.
The key fingerprint is:
fb:4d:f5:38:d4:ea:aa:95:f4:0e:73:0c:95:62:1a:dc joe@gil.beowulf.cim
bash$ cp .ssh/id_dsa.pub .ssh/authorized_keys2

You then need to log into each machine once in order to add the host keys to your .ssh/known_hosts file. The machine names can be found on the naming page.

If you have set up SSH correctly, you will be able to run commands on other machines within the cluster without typing a password:

bash$ ssh miles hostname
miles.beowulf.cim
bash$