Kong
fix(conf): remove `CNAME` from default `dns_order` option
Summary
DNS servers are capable of performing recursive lookups on behalf of clients and DNS client could directly extract IP addresses from RRs due to https://github.com/Kong/kong/pull/13002. Consequently, clients often don't need to query CNAME records.
The impact on customers is that when they use the default dns_order option without explicit configuration, their local DNS servers won't get any CNAME requests, and there won't be CNAME dereferencing for those queries.
Checklist
- [x] The Pull Request has tests
- [x] A changelog file has been created under
changelog/unreleased/kongorskip-changeloglabel added on PR if changelog is unnecessary. README.md - [ ] There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE
Issue reference
Fix KAG-4606
This PR removes Kong's DNS client's handling of CNAME. As a result, the logic for CNAME dereferencing and recursive loop detection becomes unnecessary and can be removed. However, removing them requires some effort, so for now, they're left as is.
isn't this a breaking change?
I reconsidered it, and changing the default behavior is a breaking change. I'll modify the type in the changelog.
However, users can actually be unaware of this behavior, because CNAME can still be configured in dns_order. This PR does not remove the CNAME-processing logic from DNS client. This means that customers can seamlessly upgrade to this version of the PR, whether they are using the default dns_order or have explicitly configured dns_order with CNAME, such as (dns_order=LAST,A,CNAME).
What users will notice is that when they use the default dns_order option without explicit configuration, their local DNS servers will not receive any CNAME requests and there is no CNAME dereferencing for that query.
hold it , because https://github.com/Kong/kong/pull/13002 has been reverted. We need to fix the regression of https://github.com/Kong/kong/pull/13002, then we could merge this pr.