The following configuration steps are provided as an example. You must configure SSH at the OS level on each host in the cluster.
As cluster administrator, run ssh-keygen to generate the private/public key pairs:
Generating public/private rsa key pair
Enter file in which to save the key (/home/user_name/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Your identification has been saved in /home/user_name/.ssh/id_rsa.
Your public key has been saved in /home/user_name/.ssh/id_rsa.pub.
Go to $HOME/.ssh and copy id_rsa.pub as $HOME/.ssh/authorized_keys.
cp -p id_rsa.pub authorized_keys
Note that this step assumes $HOME is a shared directory; if not, you must copy the .ssh directory to each host in the cluster.
Upon completion of these steps, you should be able to run SSH without being prompted for a password.