SSH Login without Password

To login in SSH without password, we need to do the following:
1. Generate a key pair (private key and public key) in Server A

ssh-keygen -t rsa

2. Copy the public key from Server A to Server B.

scp id_rsa.pub testuser:[server_B_ip_address]:/home/testuser/.ssh

3. In Server B, add that public key into authorized_keys file.

cat id_rsa.pub >> authorized_keys

4. Verify it from Server A.

ssh testuser@[server_B_ip_address]