https://medium.com/aws-activate-startup-blog/building-a-serverless-dynamic-dns-system-with-aws-a32256f0a1d8
Base of proof of concept
Setting up a lambda with terraform
Gave me a hint about the following error:
curl http://_ff5c13ee6052045e98d30570a20e010d.ddns.rockygray.com
curl: (6) Could not resolve host: _ff5c13ee6052045e98d30570a20e010d.ddns.rockygray.com
Requests to the custom domain need to be over https!
TODO: figure out http -> https redirect...