ssh-keygen

ssh-keygen -- authentication key generation, management and conversion

-F hostname
             Search for the specified hostname in a known_hosts file, listing
             any occurrences found.  This option is useful to find hashed host
             names or addresses and may also be used in conjunction with the
             -H option to print found keys in a hashed format.


 -R hostname
             Removes all keys belonging to hostname from a known_hosts file.
             This option is useful to delete hashed hosts (see the -H option
             above).


ssh-keygen -f "/root/.ssh/known_hosts" -R [Node_IP]