faul_sname comments on Host Keys and SSHing to EC2

faul_sname 18 Apr 2025 17:54 UTC
2 points
0
If you were to edit ~/.ssh/known_hosts to add an entry for each EC2 host you use, but put them all under the alias ec2, that would work.

So your ~/.ssh/known_hosts would look like
```
ec2 ssh-ed25519 AAAA...w7lG
ec2 ssh-ed25519 AAAA...CxL+
ec2 ssh-ed25519 AAAA...M5fX
```
That would mean that host key checking only works to say “is this any one of my ec2 instances” though.

Edit: You could also combine the two approaches, e.g. have
```
ec2 ssh-ed25519 AAAA...w7lG
ec2_01 ssh-ed25519 AAAA...w7lG
ec2 ssh-ed25519 AAAA...CxL+
ec2_02 ssh-ed25519 AAAA...CxL+
ec2 ssh-ed25519 AAAA...M5fX
ec2_nf ssh-ed25519 AAAA...M5fX
```
and leave ssh_ec2nf as doing ssh -o "StrictHostKeyChecking=yes" -o "HostKeyAlias=ec2nf" "$ADDR" while still having git, scp, etc work with $ADDR. If “I want to connect to these instances in an ad-hoc manner not already covered by my shell scripts” is a problem you ever run into. I kind of doubt it is, I was mainly responding to the “I don’t see how” part of your comment rather than claiming that doing so would be useful.