aws
[EKS] [CoreDNS]: Support trafficDistribution in addition to annotationTopologyMode
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Tell us about your request Add an option in EKS Addon CoreDNS config to enable trafficDistribution on the kube-dns / coredns service.
Which service(s) is this request for? EKS
Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?
When resolving through CoreDNS, you need to resolve in the same zone as your pod to avoid cross-AZ traffic on NLB and other services. Topology Aware Routing allows that but doesn't fully work when zones aren't balanced in term of requests.
trafficDistribution: PreferClose (And PreferSameZone in the future) solves that issue by enforcing that traffic is routed on the same zone unless no Endpoints are available. trafficDistribution has been stable since 1.33 and enabled by default.
Are you currently working around this issue?
Manually added .spec.trafficDistribution: PreferClose to the kube-dns service.
Additional context Same context as #2310. Traffic Distribution is only an improvement over TAR for this use-case.
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Hello Sayrus 👋 Thank you for opening an issue in the project. The team will review the issue and post back.
Hey @eqe-aws @mikestef9, looking for the review & post back. Checked containers-roadmap and I found no mention to this. Since the state of this feature is stable and enabled by default in K8s 1.33, which was released for EKS in May 29, 2025, would be cool to have it in CoreDNS ASAP.
