Comment by CGamesPlay

I often SSH into ephemeral servers like autoscaling EC2 instances. The host key checking is unnecessary and annoying, so I use a different SSH command for that:

    function ec2_ssh
      ssh -F ~/.ssh/ec2_config $argv
    end

And then in the ec2_config file…

    StrictHostKeyChecking=no
    UserKnownHostsFile=/dev/null