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Chapter 4.5 - Network Policies

Learning Objectives​

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

  • Understand Network Policies
  • Create traffic rules
  • Isolate namespaces
  • Secure communication between Pods

What is a Network Policy?​

A Network Policy defines the allowed network traffic rules between Pods.

By default: All traffic is allowed. Network Policies restrict it.

Network Policy Example​

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-frontend-to-backend
  namespace: default
spec:
  podSelector:
    matchLabels:
      app: backend
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: frontend
    ports:
    - protocol: TCP
      port: 8080

Effect: Only Pods with app=frontend can access app=backend Pods on port 8080.

Summary​

In this chapter, you learned:

Network Policy: Network traffic rules between Pods
Isolation: Restrict communication
Selectors: Based on labels
Ingress/Egress: Incoming/outgoing traffic

Next Steps​

Chapter 4.6: Endpoints and EndpointSlices
Lab 4.3: Network Policies

Chapter created: December 2024