1.login in as the oracle user
2.create the .ssh directory in the oracle user's home directory and set the correct permissions on it:
mkdir ~/.ssh
chmod 700 ~/.ssh
3.genterate a RSA key
/usr/bin/ssh-keygen -t rsa
4.generate a DSA key
/usr/bin/ssh-keygen -t dsa
5.on the local node,create authorized_keys
$touch ~./ssh/authorized_keys
$cd ~/.ssh
$ls
6.copy the contents of the ~/.ssh/id_rsa.pub and ~/.ssh/id_dsa.pub files to the file ~/.ssh/authorized_keys
$ssh node1 cat  /home/oracle/.ssh/id_rsa.pub>>authorized_keys
$ssh node1 cat /home/oracle/.ssh/id_dsa.pub>>authorized_keys
$ssh node2 cat / home/oracle/.ssh/id_rsa.pub>>authorized_keys
$ssh node2 cat /home/oracle/.ssh/id_dsa.pub>>authorized_keys
6.use scp or sftp to copy the authorized_keys file to the oracle user .ssh directory on a remote node
$scp authorized_keys node2:/home/oracle/.ssh/
7.change the permissions on the oracle user's /.ssh/authorized_keys file on all cluster nodes:
$chmod 600 ~/.ssh/authorized_keys