There are situations when host id might be changed a few times during fast, automatic, and massive host deployment. Ssh client begins to complain on changed host id.
[root@builder2 ~]# ssh webmel53 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. The fingerprint for the RSA key sent by the remote host is 7f:14:74:68:ca:9e:e2:ec:1c:44:8c:ea:29:a9:84:60. Please contact your system administrator. Add correct host key in /root/.ssh/known_hosts to get rid of this message. Offending key in /root/.ssh/known_hosts:80 RSA host key for webmel53 has changed and you have requested strict checking. Host key verification failed.
Quick and easy step follows:
[root@builder2 ~]# ssh-keygen -R !$ ssh-keygen -R webmel53 /root/.ssh/known_hosts updated. Original contents retained as /root/.ssh/known_hosts.old