Kubernetes Service Types and DNS-Based Discovery#

Services are the stable networking abstraction in Kubernetes. Pods come and go, but a Service gives you a consistent DNS name and IP address that routes to the right set of pods. Choosing the wrong Service type or misunderstanding DNS discovery is behind a large percentage of connectivity failures.

Service Types#

ClusterIP (Default)#

ClusterIP creates an internal-only virtual IP. Only pods inside the cluster can reach it. This is what you want for internal communication between microservices.

Kubernetes Troubleshooting Decision Trees#

Troubleshooting Kubernetes in production is about eliminating possibilities in the right order. Every symptom maps to a finite set of causes, and each cause has a specific diagnostic command. The decision trees below encode that mapping. Start at the symptom, follow the branches, run the commands, and the output tells you which branch to take next.

These trees are designed to be followed mechanically. No intuition required – just execute the commands and interpret the results.