CKA — Services & Networking
Chapter Overview
Services & Networking is one of the most important domains on the CKA exam — it carries 20% of the total weight.
This chapter is all about how Pods communicate with each other and how Services provide stable network endpoints to expose them. In Kubernetes, Pods are ephemeral — they come and go. Services solve the problem of giving a stable IP and DNS name to a set of Pods so that other components (inside or outside the cluster) can reliably reach them.
By the end of this chapter, you’ll understand how traffic flows inside a Kubernetes cluster, how DNS resolution works, how kube-proxy routes packets, and how to troubleshoot networking issues — all critical skills for the CKA exam.
What You’ll Learn
| # | Topic | What’s Covered |
|---|---|---|
| 1 | Service Types | ClusterIP, NodePort, LoadBalancer, ExternalName, Headless |
| 2 | Endpoints & EndpointSlices | How endpoints work, manual management |
| 3 | Service DNS | FQDN format, Pod DNS policies, debugging |
| 4 | kube-proxy Modes | iptables vs IPVS, session affinity |
| 5 | Pod-to-Pod Communication | Networking model, CNI, cross-node |
| 6 | Hands-On Lab | Create Services, test DNS, debug connectivity |
CKA Exam Relevance
| Domain | Weight |
|---|---|
| Services & Networking | 20% |
The CKA exam will test your ability to:
- Create and configure different Service types
- Understand how DNS resolution works inside a cluster
- Debug network connectivity issues between Pods and Services
- Understand how kube-proxy implements Service routing
- Work with Endpoints and EndpointSlices
You’ll need to be fast with kubectl expose, know DNS naming conventions by heart, and be comfortable debugging connectivity from inside Pods.
Prerequisites
Before diving into this chapter, make sure you’re comfortable with:
- Pods and Deployments — You should know how to create and manage Pods and Deployments
- Labels and Selectors — Services use label selectors to find target Pods
- Namespaces — DNS resolution depends on namespaces
- kubectl basics — You’ll be running a lot of imperative commands
