I have a Google cloud server that currently runs Ubuntu 16.04. I have not done much to it in years and it always ran great.
Somehow or other, for the first time, it experienced downtime today of about 15 minutes.
After I restarted it, ssh gives me a warning "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!". I am certain that I, the sole administrator, did not initiate any such changes. Last time I logged in, was yesterday.
While I can, obviously, change the known hosts file and adjust to the new host key, I am extremely disturbed by this change and I am suspecting that something is amiss. Would anyone have any clue as to why this count happen?
I did log on to it from a google cloud ssh window and, on the first look, it runs as usual running my website. However, right now I am overwhelmed with paranoia and what it could be.