KUBE-DNS Implementation in K8S Cluster:

KUBE-DNS is the backbone of SERVICE DISCOVERY implementation inside the K8S Cluster,

It has pods with name kube-dns (deployment) and has two important containers, named [kubedns , dnsmasq] in each pod.

service/kube-dns - which exposes those pods via cluster-ip which becomes the DNS server IP of every pod created inside the K8S cluster (when dnsPolicy: ClusterFirst is set, which is the default behaviour).