Troubleshooting Services and Networking

Introduction

This is the last lesson of the Troubleshooting domain, the largest of the CKA (30%, Kubernetes v1.35). The official curriculum item is troubleshoot services and networking. Networking problems are a favourite exam scenario because a single symptom, "the application is not reachable", can hide a wrong selector, a wrong port, a missing endpoint, a DNS failure, a NetworkPolicy, a broken CNI plugin, or a bad Ingress or Gateway route. The skill is not memorising causes; it is following the path of a request layer by layer and testing each hop.