Post author here. A bunch of stuff was glossed over as the post was more focused on the stack's history and evolution than specific technical details.

Ideally we hope to provide some followup posts that go deeper into technical detail about key pieces of the stack (DNS, initramfs framework, job broker, GCP usage, etc).

It's my hunch that they fixed "curating DNS by hand" with service discovery in another method. If you're just using DNS to name internal servers, big whoop. Unless you're using those DNS names for service discovery. Then you've got a big problem. But putting those things in a DB doesn't magically solve it.

It sounds like they went to another method for service discovery, then created DNS entries from a DB either dynamically by registering in a zone or just a regular trigger pulled on DB update. Either way, it sounds like they moved the scary stuff to another level/service in the stack.

Also, linters exist for DNS and can be automated even with manual edits. Jenkins + gerrit makes easy work for this.