Does anyone know a nice way of running a fixed auto-scaling group of 1 but its ENI not refer one that exists?

Yeah, no worries, this site could be doing enough NAT G/W processed traffic to make it worth it, I have stuff already there so I could “re-enable” NAT G/Ws if it became a pain or proved unreliable in practice.

Yes, the route modifications is the other way of doing it, AWS already have an article on it that I read that references the healthcheck stuff etc. I figured from a terraform perspective, having an ASG with the user data stuff handling the ENI connection would be cleaner and wouldn’t require some ignores which route modifications would :shrug:

Thanks for your help though, glad to hear I’m not going down the wrong road, much appreciated.

We’re in the enterprise B2B SAS space, so we have to have static IPs for a lot of our customer connections, so i hear you