Services & Networking

Every Pod gets its own unique, routable IP address. Pods communicate with each other directly using those IPs without NAT, as if they were on one flat network. This is implemented by a CNI plugin, which you do not configure on CKAD.

Yes. All containers in a Pod share one network namespace, meaning they share a single Pod IP and can reach each other over localhost. They must use distinct ports because they share the same loopback interface.

Because they share one network namespace and one localhost interface. Two processes cannot bind the same port on the same interface, so one container's bind will fail with an address-in-use error.

1) Pods on a node can communicate with all Pods on all nodes without NAT. 2) Agents on a node (like kubelet) can communicate with all Pods on that node. 3) A Pod sees its own IP as the same IP others use to reach it.

CoreDNS. It runs as a Deployment in kube-system and acts as the cluster DNS server, resolving Service and Pod names to IPs. It replaced the older kube-dns.

<service-name>.<namespace>.svc.cluster.local. For example, a Service named db in namespace prod resolves at db.prod.svc.cluster.local. cluster.local is the default cluster domain.