AWS (and more generally anything running cloud-init) does this fairly well - it prints it to the console log. I use this, and I have on a couple of occasions bo

AWS (and more generally anything running cloud-init) does this fairly well - it prints it to the console log. I use this, and I have on a couple of occasions booted a new instance and mounted the old one's disk when my known_hosts file got trashed by mistake, so I could re-establish a trust path. Of course you have to know to go there, wait for the console log to sync (for some reason AWS takes a few minutes ... I wonder if it's backed by some eventual-consistency object store), and scroll down in the log. Come to think of it, it would be real cool if OpenSSH had a -o Fingerprint=ab:cd:ef... option you could pass, so that they could give you a single command to copy and paste to your terminal.