How to set up SSH password-free logon on CentOS/RHEL

The following steps are successfully tested on CentOS 5/6/7, RHEL 5/6/7, and Oracle Linux 6/7.

Node 1: 192.168.0.9 node 2: 192.168.l.10

Step 1:

Test the connection and access from node 1 to Node 2:

[Root @ node1 ~] # Ssh root@192.168.0.10
The authenticity of host' 192. 168.0.10 (192.168.0.10) 'can't be established.
RSA key fingerprint is 6d: 8f: 63: 9b: 3b: 63: e1: 72: b3: 06: a4: e4: f4: 37: 21: 42.
Are you sure you want to continue connecting (yes/no )? Yes
Warning: Permanently added '192. 168.0.10 '(RSA) to the list of known hosts.
Root@192.168.0.10's password:
Last login: Thu Dec 10 22:04:55 2015 from 192.168.0.1
[Root @ node2 ~] #
Step 2:

Use the ssh-key-gen command to generate the public key and private key. Note that the private key can be encrypted to enhance security.

[Root @ node1 ~] # Ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/. ssh/id_rsa ):
Enter passphrase (empty for no passphrase ):
Enter same passphrase again:
Your identification has been saved in/root/. ssh/id_rsa.
Your public key has been saved in/root/. ssh/id_rsa.pub.
The key fingerprint is:
B4: 51: 7e: 1e: 52: 61: cd: fb: b2: 98: 4b: ad: a1: 8b: 31: 6d root@node1.ehowstuff.local
The key's randomart image is:
+ -- [RSA 2048] ---- +
|. ++ |
| O |
| O. |
|. O +... |
| S .. |
|... |
| O E oo. o |
| = Ooo. |
|. O. o. |
+ ----------------- +
Step 3:

Use the ssh-copy-id command to copy or upload the public key to the remote host, and append the id file to ~ of node 2 ~ /. Ssh/authorized_keys:

[Root @ node1 ~] # Ssh-copy-id-I ~ /. Ssh/id_rsa.pub 192.168.0.10
Root@192.168.0.10's password:
Now try logging into the machine, with "ssh '192. 168.0.10 '", and check in:
. Ssh/authorized_keys
To make sure we haven't added extra keys that you weren't expecting.
Step 4:

Verify password-free SSH logon node 2:

[Root @ node1 ~] # Ssh root@192.168.0.10
Last login: Sun Dec 13 14:03:20 2015 from www. ehowstuff. local

Have you found that configuring ssh password-free logon is very simple? Now we have finished setting up SSH password-free logon on CentOS/RHEL. I hope it will be helpful to you.