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Comment by djb_hackernews | Hacker News Reader

It's not clear how this is different from what is currently possible. I'm not a route53 guru but can't you already a) create a subdomain microservice.mydomain.com b) create instances c) add the instances IP address to an A or AAAA record for the subdomain.

Is it that they didn't have APIs for these operations and now they do?

I know I'm missing something.

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If I'm reading the underlying docs correctly, previously you would have called ChangeResourceRecordSets[0] with a quite verbose XML document. It looks like you'd need to first query for the existing RR set, modify it, then update it, and deal with potential race conditions if two service instances are starting concurrently. Technically possible, but quite a bit of complexity.

Now with auto-naming, you create a service[1], then a service instance calls RegisterInstance[2] on start-up with a much simpler JSON payload.

0: https://docs.aws.amazon.com/Route53/latest/APIReference/API_...

1: https://docs.aws.amazon.com/Route53/latest/APIReference/API_...

2: https://docs.aws.amazon.com/Route53/latest/APIReference/API_...

There were APIs to do the operations you mentioned. I think for most services an ELB would do the trick; create an ELB, add instances to it, create a CNAME or Alias to the ELB.

The one time I've wanted this is with auto scaling groups for services that don't use ELBs. I haven't found docs on it, but if this could be used to add/remove DNS records based on auto scaling events that would be useful. It would save from using lifecycle hooks to trigger a Lambda function.

Also this seems to be a larger service discovery play, it just doesn't seem very fleshed out yet.

It's not a long article, like three paragraphs. The complexity is handling health checks and the like. If one of your endpoints goes down, you want to update the DNS record to remove it. Which means you have to make or use software that continuously monitors your endpoints and updates DNS accordingly. Now Route 53 will do those health checks for you automatically.

When I first read the article I was under the impression that now one would be able to connect a zone with an autoscaling group (and, as you mentioned, avoid allocation internal ELBs), but it looks like it's really just some sugar on top of the existing API.

Am I right?

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