ssh passwordless login

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Configuring password authentication or login via ssh. This post explains how to enable password less authentication between two nodes. The configuration is very simple. You have to generate dsa public and private keys of the server which you want to login from  and copy that to the authorized_keys of the host you want to login to without password. We will generate the keys using the command ssh-keygen.

We have two nodes:
Node1 - hb_test1.lap.work
Node2 - hb_test2.lap.work

On node1:
Generate the key:

[root@hb_test1 ~]# ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/root/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_dsa.
Your public key has been saved in /root/.ssh/id_dsa.pub.
The key fingerprint is:
9f:5d:47:6b:2a:2e:c8:3e:ee:8a:c2:28:5c:ad:57:79 root@hb_test1.lap.work

Pass the key to node2:
[root@hb_test1 ~]# scp .ssh/id_dsa.pub hb_test2.lap.work:/root/.ssh/authorized_keys

On node2:
Generate the key:

[root@hb_test2 ~]# ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/root/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_dsa.
Your public key has been saved in /root/.ssh/id_dsa.pub.
The key fingerprint is:
40:66:t8:bd:ac:bf:68:38:22:60:d8:9f:18:7d:94:21 root@hb_test2.lap.work

Pass the key to node1:
[root@hb_test2 ~]# scp .ssh/id_dsa.pub hb_test1.lap.work:/root/.ssh/authorized_keys

Now you will be able to login to node1 to node2 and vice versa without passwords.