Kubernetes Pod DNS Resolution

@mk_sta 's answer a bit easier to work with you can run this one liner to test your DNS:

kubectl run busybox --image=busybox --rm --attach --command -- sh -c "cat /etc/resolv.conf; nslookup $POD.$NAMESPACE.pod.cluster.local"

Example output:

If you don't see a command prompt, try pressing enter.

Server:         100.64.0.10
Address:        100.64.0.10:53


*** Can't find $POD.$NAMESPACE.pod.cluster.local: No answer

deployment.apps "busybox" deleted

Bonus is that it deletes the deployment/pods after running.

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For me the problem was that my pods are in a statefulset and therefore Pod DNS resolution is a bit different. You have to use (for example):

web-{0..N-1}.nginx.default.svc.cluster.local

pod-N.$GOVERNING_STATEFULSET.$NAMESPACE.svc.cluster.local

https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/

That's one thing that can go wrong. You may want to provide more info about your particular case.