What is Kubernetes NetworkPolicy?

Question

Accepted Answer

**NetworkPolicy** — controls traffic flow between Pods.

```yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-frontend-only
  namespace: production
spec:
  podSelector:
    matchLabels:
      app: backend
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: frontend
    ports:
    - protocol: TCP
      port: 8080
---
# Deny all ingress by default
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny-ingress
spec:
  podSelector: {}
  policyTypes:
  - Ingress
```

**Requirements:**
- CNI that supports NetworkPolicy (Calico, Cilium, Weave).
- Default: all traffic allowed if no policy exists.

DevOps: What is Kubernetes NetworkPolicy?