OHPC-SSH-HOSTKEY-CHANGE-FIX

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You may get the error below when trying to SSH to the new ELSA cluster from your Mac, PC or when using the >_ELSA OpenHPC Cluster Shell Access terminal in Open OnDemand. 

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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:Tydfgvr4fQRlh2L/sqHu6gUR80O1DhDLBeL99HKaIQc.
Please contact your system administrator.
Add correct host key in ~/ssivy/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in ~/.ssh/known_hosts:154
ECDSA host key for elsa.hpc.tcnj.edu has changed and you have requested strict checking.
Host key verification failed.

To resolve the issue and remove the error message, follow the instruction below based on the platform from where you are running the SSH command.

Windows

You will most likely be prompted by your SSH/terminal program to confirm the change in the SSH host key fingerprint. Click the Ok/Confirm/etc. button to accept the new key.

Mac

Open a terminal window (you're probably already using the terminal window).
Type the following before at the terminal prompts. 

ssh-keygen -R elsa.hpc.tcnj.edu
ssh-keygen -R 159.91.50.30

Retry your SSH command again.
You will probably be asked to accept/confirm the SSH host key fingerprint. Type yes and press the ENTER or RETURN key. This should only happen the first time after running the ssh-keygen commands.

Open OnDemand Web Portal

While this error doesn't prevent you from opening an >_ELSA OpenHPC Cluster Shell Access terminal window, you will get the error message each time. To get rid of that message, follow these steps.

Type the following at the Linux command prompt. 

ssh-keygen -R elsa.hpc.tcnj.edu
ssh-keygen -R 159.91.50.30

Type exit and close the browser tab with the terminal. Open a new >_ELSA OpenHPC Cluster Shell Access terminal.
You may see a message about adding a new host key. This should only happen the first time after running the ssh-keygen commands.

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