To configure SSH, copy all the generated keys on all cluster node members into an authorized keys file that is identical on each node.

1. On the local node, change directories to the .ssh directory in the Oracle Grid Infrastructure owner's home directory (typically, either grid or oracle). Then, add the DSA key to the authorized_keys file using the following commands:

   $ cat id_dsa.pub >> authorized_keys 
   $ ls

   In the .ssh directory, you should see the id_dsa.pub keys that you have created, and the file authorized_keys.
2. On the local node, use SCP (Secure Copy) or SFTP (Secure FTP) to copy the authorized_keys file to the oracle user .ssh directory on a remote node. The following example is with SCP, on a node called node2, with the Oracle Grid Infrastructure owner grid, where the grid user path is /home/grid:

   [grid@node1 .ssh]$ scp authorized_keys node2:/home/grid/.ssh/ 

   1. You are prompted to accept a DSA key. Enter Yes, and you see that the node you are copying to is added to the known_hosts file.
   2. When prompted, provide the password for the grid user, which should be the same on all nodes in the cluster. The authorized_keys file is copied to the remote node.
   Your output should be similar to the following, where xxx represents parts of a valid IP address:

   [grid@node1 .ssh]$ scp authorized_keys node2:/home/grid/.ssh/
   The authenticity of host 'node2 (xxx.xxx.173.152) can't be established.
   DSA key fingerprint is 7e:60:60:ae:40:40:d1:a6:f7:4e:zz:me:a7:48:ae:f6:7e.
   Are you sure you want to continue connecting (yes/no)? yes
   Warning: Permanently added 'node1,xxx.xxx.173.152' (dsa) to the list
   of known hosts
   grid@node2's password:
   authorized_keys	     100%	     828	     7.5MB/s      00:00

3. Using SSH, log in to the node where you copied the authorized_keys file. Then change to the .ssh directory, and using the cat command, add the DSA keys for the second node to the authorized_keys file, clicking Enter when you are prompted for a password, so that passwordless SSH is set up:

   [grid@node1 .ssh]$ ssh node2 [grid@node2 grid]$ cd .ssh [grid@node2 ssh]
   $ cat id_dsa.pub  >> authorized_keys

4. Repeat steps 2 and 3 from each node to each other member node in the cluster.
5. When you have added keys from each cluster node member to the authorized_keys file on the last node you want to have as a cluster node member, then use scp to copy the authorized_keys file with the keys from all nodes back to each cluster node member, overwriting the existing version on the other nodes. To confirm that you have all nodes in the authorized_keys file, enter the command more authorized_keys, and determine if there is a DSA key for each member node. The file lists the type of key (ssh-dsa), followed by the key, and then followed by the user and server. For example:

   ssh-dsa AAAABBBB . . . = grid@node1

   The grid user's /.ssh/authorized_keys file on every node must contain the contents from all of the /.ssh/id_dsa.pub files that you generated on all cluster nodes.