I recently worked on prototyping a public DNS server using CoreDNS. CoreDNS normally provides serving DNS zone data through files, however it also allows you to proxy to a backend endpoint via gRPC. I used this DNS server as the nameserver for a domain with thousands of subdomains.
This approach allows you to write a custom DNS server in any popular language,
and serve records stored in an external datastore (like a redis cache, mysql
database). In this article, I’ll go over the sample
backend I’ve built.