aws / aws/eks-anywhere

DNS resolve through a coredns pod on a different node timeout

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Description

What happened:
We have a EKSA cluster with persisting issue of DNS resolve:

If using coredns pod on the same node, it's fine (command "dig @<coredns IP> kubernetes.default" instantly responds)
If using coredns pod on a different node, command "dig @<coredns IP> kubernetes.default" timeout.
However, ping <coredns IP> always works

What you expected to happen:
command "dig @ kubernetes.default" instantly reponds no matter which coredns in use.

How to reproduce it (as minimally and precisely as possible):

kubectl run -it --rm --restart=Never --image=infoblox/dnstools:latest dnstools
dnstools# ping <coredns IP on different node>
dnstools# dig @<coredns IP on same node> kubernetes.default
dnstools# dig @<coredns IP on different node> kubernetes.default

Anything else we need to know?:
We have another cluster with the same issue, but now self-healed.

Environment:

  • EKS Anywhere Release:
  • EKS Distro Release:

Contributor guide

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The issue names no repository files or tests. Start by reproducing the cross-node behavior with the provided kubectl, ping, and dig commands, then inspect the DNS networking path between nodes. Done means dig against a CoreDNS pod on another node responds reliably, with the relevant EKS Anywhere and EKS Distro versions recorded.

Written by the indexing model from the issue text.

Assessment

Tech stack
aws, kubernetes
Domain
infrastructure, networking
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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