DNS

• Debugging DNS Resolution

Cluster Environment Test

Create DNS utils pod

kubectl apply -f https://k8s.io/examples/admin/dns/dnsutils.yaml

kubectl -n default get pods dnsutils

kubectl -n default exec dnsutils -- nslookup kubernetes.default

Check local DNS configuration

kubectl -n default exec dnsutils -- cat /etc/resolv.conf

Add Custom Host Address

kubectl -n kube-system edit configmap/coredns

apiVersion: v1
data:
  Corefile: |
    .:53 {
        ...
        ...
        hosts {
          192.168.0.101 example.com www.example.com
          fallthrough
        }
    }
kind: ConfigMap

kubectl -n kube-system rollout restart deploy coredns

kubectl apply -f https://k8s.io/examples/admin/dns/dnsutils.yaml
kubectl -n default exec dnsutils -- nslookup www.example.com