K8s DNS Troubleshooting

kubectl apply -f testpod-dnsutils.yaml

 kubectl exec -i -t dnsutils -- nslookup cisco.com 10.x.x.x
 kubectl exec -i -t dnsutils -- nslookup cisco.com
 kubectl logs -n 10 --namespace=kube-system -l k8s-app=kube-dns
 kubectl describe cm -n kube-system -l k8s-app=kube-dns
 kubectl get configmap coredns -n kube-system -o yaml >tmp_coredns.yaml
 kubectl get ep kube-dns --namespace=kube-system
  kubectl -n kube-system rollout restart deployment coredns
   kubectl -n kube-system get configmap coredns
   kubectl rollout restart -n kube-system deployment/coredns
   k get pods -o wide --all-namespaces | grep "core|dnsu"
   kubectl create deployment dnsutils --image=gcr.io/kubernetes-e2e-test-images/dnsutils:1.3 -- sleep 3600

sudo microk8s enable ingress dns:10.206.232.247
kubectl -n kube-system get configmap coredns -oyaml
kubectl get pods -o wide --all-namespaces | grep "core\|dnsu"
kubectl run dnsutils  -n default --image=gcr.io/kubernetes-e2e-test-images/dnsutils:1.3 -- sleep 3600
kubectl -n default exec -i -t dnsutils -- nslookup cisco.com 10.x.x.x
kubectl -n default exec -i -t dnsutils -- nslookup cisco.com 10.152.183.10
kubectl -n default exec -i -t dnsutils -- nslookup cisco.com
curl -kH "Host: monitor.mktp.io" https://10.x.x.x

kubectl -n default delete pod dnsutils
sudo tcpdump -vvni any port 4789
for i in {1..3}; do kubectl -n default exec -i -t dnsutils$i -- nslookup cisco.com; done

for i in {1..3}; do
  echo "dnsutils$i"
  kubectl -n default run dnsutils$i --image=gcr.io/kubernetes-e2e-test-images/dnsutils:1.3 -- sleep 3600
  sleep 20
  kubectl -n default exec -i -t dnsutils$i -- nslookup cisco.com
done