Issue with SSH Key while upgrading Gitlab 11 -> 14

Hello all,

I upgraded an old Gitlab 11.9.4 instance to Gitlab 14.1.x (all using dockers), I have gone through all the upgrade path and middle versions that are required and everything is working rather smoothly.

The only issue I am encountering is that users that connected to my Gitlab using SSH are now getting an error of “Remote Host Identification has Changed” and “Possible DNS Spoofing Detected”. I am at a loss to why is it happening because I copied all the keys from my old /etc/ssh dir to the new one.

I read about the suggestions to delete the known_hosts files, I would like to avoid that. I did try it just to see what the difference is and it seems that in the new Gitlab instance, the “hostname” that I get in the known_hosts file is composed of both the hostname and the IP in the next format: "<hostname>,<ip> ...." . This is in contrast to the older gitlab instance where the hostname in known_hosts is just the <hostname> - I assume this might be the issue.

Has anyone has encountered this issue? Would really appreciate your help.