[CKA] Mock Test - DNS lookup

docs : https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/

DNS for Services and Pods

controlplane ~ ➜  k run nginx-resolver --image=nginx
pod/nginx-resolver created

controlplane ~ ➜  k get po
NAME                          READY   STATUS              RESTARTS   AGE
nginx-critical-node01         1/1     Running             0          2m31s
nginx-deploy-58f87d49-wmsmz   1/1     Running             0          18m
nginx-resolver                0/1     ContainerCreating   0          1s
redis-storage                 1/1     Running             0          28m
super-user-pod                1/1     Running             0          26m
use-pv                        1/1     Running             0          22m

controlplane ~ ➜  k expose pod nginx-resolver --name=nginx-resolver-service --port=80
service/nginx-resolver-service exposed

controlplane ~ ➜  k run busybox --image=busybox:1.28 -- sleep 4000
pod/busybox created

controlplane ~ ➜  k exec busybox -- nslookup nginx-resolver-service > /root/CKA/nginx.svc

controlplane ~ ➜  k get po -o wide
NAME                          READY   STATUS    RESTARTS   AGE     IP             NODE     NOMINATED NODE   READINESS GATES
busybox                       1/1     Running   0          52s     10.244.192.7   node01   <none>           <none>
nginx-critical-node01         1/1     Running   0          5m6s    10.244.192.4   node01   <none>           <none>
nginx-deploy-58f87d49-wmsmz   1/1     Running   0          21m     10.244.192.5   node01   <none>           <none>
nginx-resolver                1/1     Running   0          2m36s   10.244.192.6   node01   <none>           <none>
redis-storage                 1/1     Running   0          31m     10.244.192.1   node01   <none>           <none>
super-user-pod                1/1     Running   0          29m     10.244.192.2   node01   <none>           <none>
use-pv                        1/1     Running   0          25m     10.244.192.3   node01   <none>           <none>

controlplane ~ ✖ k exec busybox -- nslookup 10-244-192-6.default.pod.cluster.local > /root/CKA/nginx.pod

 

kubectl run nginx-resolver --image=nginx kubectl expose pod nginx-resolver --name=nginx-resolver-service --port=80 --target-port=80 --type=ClusterIP

kubectl run test-nslookup --image=busybox:1.28 --rm -it --restart=Never -- nslookup nginx-resolver-service kubectl run test-nslookup --image=busybox:1.28 --rm -it --restart=Never -- nslookup nginx-resolver-service > /root/CKA/nginx.svc

kubectl get pod nginx-resolver -o wide kubectl run test-nslookup --image=busybox:1.28 --rm -it --restart=Never -- nslookup <P-O-D-I-P.default.pod> > /root/CKA/nginx.pod