Headless Services, ExternalName, and EndpointSlices

A ClusterIP Service hands you a single virtual IP and load-balances traffic behind it. That works for stateless backends, but some workloads need more: databases forming replication clusters need to address each peer by name, cache nodes electing leaders need to discover every member, and replicas initializing from a primary need a stable DNS entry that survives Pod restarts. That is where headless Services come in.

This lesson covers three Service features that extend beyond the standard types explored in Service Types: headless Services that expose individual Pod IPs through DNS, ExternalName Services that map cluster DNS to external hostnames, and the EndpointSlice API that underpins all of it with scalable, topology-aware endpoint tracking. All three fall within the CKA Services & Networking domain (20%).