I operate some DNS servers using BIND for around 15,000 domain names. Some customers would like to start using a Full-Site Content Delivery CDN and a requirement for this is supporting the usage of ANAME / ALIAS DNS records, which are now supported by several of the big DNS providers.
Is there a way to implement these record types on top of BIND or could you advise on how to introduce this type of functionality?
No, as those are not actual record types outlined by a standard defining document. All dynamic apex functionality is implementation specific, as there is not a standardized way of dealing with the problem. Fake record types like "ANAME" and "ALIAS", and buzzwords like "CNAME flattening" are all product specific solutions to apex aliasing.
Unless it has changed in recent history, BIND does not have a feature that allows the server software to synthesize an apex A/AAAA record based on a record outside of the zone. You will have to rely on webserver redirects, or execute a hard change to the records yourself as needed. (manually, DDNS, etc.)
