Every Pod gets an IP from the cluster's Pod range. When the Pod is deleted, the IP is released. A Deployment that replaces a Pod gives the replacement a new IP.

10:00  market-web-7c-abc  10.42.0.8   Running
10:05  market-web-7c-abc  deleted
10:05  market-web-7c-xyz  10.42.0.14  Running   <- new Pod, new IP

A client that stored 10.42.0.8 is now talking to nothing.

Service

A ServiceServiceA stable name and IP in front of a changing set of Pods. is an object with three parts:

Service market-web
  clusterIP: 10.96.248.109       stable virtual IP, allocated once
  selector:  app=market-web      which Pods are behind it
  ports:     80 -> 80            port on the IP -> targetPort on the Pod

The cluster IP never changes for the life of the Service. DNS gives the Service a name. Clients use the name; the Pods behind it can come and go.

Endpoints

The endpoints controller keeps a second object, with the same name, listing every ready Pod that matches the selector:

Endpoints market-web
  10.42.0.8:80
  10.42.0.9:80
  10.42.0.10:80

Delete a Pod and its address leaves this list. Create one and it joins. kubectl get endpoints is how you check whether a Service is pointing at anything.

kube-proxy

Each node runs kube-proxy. It watches Services and Endpoints and programs the node's packet rules so that a packet addressed to 10.96.248.109:80 is rewritten to one of the endpoint addresses.

client Pod ──▶ 10.96.248.109:80 (ClusterIP)
                    │ kube-proxy rewrites the destination
                    ├──▶ 10.42.0.8:80
                    ├──▶ 10.42.0.9:80
                    └──▶ 10.42.0.10:80

No proxy process sits in the data path. The rewrite happens in the kernel.