ON EACH HOST:
Log in as oracle

$ ssh-keygen –t rsa
$cd .ssh
$cat id_rsa.pub > authorized_keys
$chmod 600 *

Then concatenate all the authorized_keys files into one file of the same name and ensure this is on all the hosts in the .ssh directory with protection of 600.

ON EACH HOST:
Enter the following command changing the hostname to each hostname in the cluster and then changing the hostname to each fully qualified hostname in the cluster.

   $ ssh hostname date
   $ ssh hostname.domainname date

e.g.
n.b. none of these commands should request a password.

 $ssh hostname date
 $ssh hostname.domain date