Kubernetes DNS

Cluster DNS: CoreDNS vs Kube-DNS DNS for Services and Pods

Test coredns

kubectl -n kube-system get pods -l k8s-app=kube-dns
kubectl -n kube-system get service kube-dns
dig @10.43.0.10 ix.de
dig @10.43.0.10 helm-operator.oas.svc.cluster.local

K8s DNS troubleshooting

Debugging DNS Resolution

kubectl apply -f https://k8s.io/examples/admin/dns/dnsutils.yaml
kubectl get pods dnsutils
kubectl exec -i -t dnsutils -- nslookup kubernetes.default