Set up password less authentication in ssh

To setup SSH passwordless authentication(User Equivalence) Between 2 Servers Linux, we can follow the below steps.

Lets assume we have only 2 servers : ServerA, ServerB and we need to configure password-less login between both the servers.

We need to login to ServerA and identify the .ssh directory exists under the home directory

In case it doesn't exist we can create it.

cd /root

mkdir .ssh

chmod 700 .ssh

On Linux for root user it is normally /root/.ssh

$ cd /root/.ssh

$ ssh-keygen -t rsa

This will create 2 files id_rsa and id_rsa.pub. One is a private key file and other is the public key file.

$ cat id_rsa.pub >> auth_keys_a

Now copy this file to the ServerB using scp utility

$ scp auth_keys_a root@ServerB:/root/.ssh

Now on ServerB identify the .ssh directory which should ideally be on the same location /root/.ssh

$ cd /root/.ssh

$ ssh-keygen - rsa

This will again create the public and private keyfile

$ cat id_rsa.pub >> auth_keys_b

Now scope this file back to ServerA

$ scp auth_keys_b root@ServerA:/root/.ssh

Now we can try to ssh between the nodes

From ServerA

ssh root@serverB

From ServerB

ssh root@serverA