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Chapter 4.4 - Kubernetes Networking

Learning Objectives

By the end of this chapter, you will be able to:

  • Understand the Kubernetes networking model
  • Identify CNI plugins
  • Understand networking rules
  • Configure cluster networking

Networking Model

Kubernetes defines a networking model with the following rules:

  1. All Pods can communicate without NAT
  2. All nodes can communicate with all Pods
  3. A Pod's IP is the same as seen by other Pods

CNI (Container Network Interface)

CNI plugins implement the networking:

  • Calico: Networking and Network Policies
  • Flannel: Simple overlay network
  • Weave: Networking with encryption
  • Cilium: eBPF-based networking

Summary

In this chapter, you learned:

Networking model: Pod/Node communication rules
CNI: Standard interface for network plugins
Plugins: Calico, Flannel, Weave, Cilium
Configuration: Via the chosen CNI plugin


Next Steps

Chapter 4.5: Network Policies
Chapter 4.6: Endpoints and EndpointSlices


Chapter created: December 2024