Problem

I'm getting the following warning when login to cluster or when login to a node:

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@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
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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 a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Please contact your system administrator.
Add correct host key in /home/XXXXX/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /home/XXXXX/.ssh/known_hosts:231
ECDSA host key for XXXXXXXXX has changed and you have requested strict checking.
Host key verification failed.

Solution

This warning indicates that the cluster's host keys have changed. Generally, It may comes from:

  • The result of system upgrades or changes in configuration on the cluster.
  • Someone is trying to intercept your ssh session.

If you are not warned about an update or a maintenance on cluster, please contact us if you receive this warning.

To be able to login to the cluster after this warning, edit the file ~/.ssh/known_hosts and remove the indicated line number (line number 231 in the example).