Create a pass-wordless ssh key

ssh-keygen.sh

# switch to the jenkins user
[root@li220-252:~] su jenkins
jenkins@li220-252:/root$ 

# Generate the key
jenkins@li220-252:~$ ssh-keygen -t rsa -C "[email protected]"
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:
72:db:5a:77:75:23:c5:58:84:59:14:31:58:52:7c:d0 [email protected]
The key's randomart image is:
+--[ RSA 2048]----+
|             .%&o|
|             +=.E|
|             . o.|
|              .  |
|      . S    . .o|
|       o o    ..o|
|        . o . .  |
|         o . .   |
|        .        |
+-----------------+