Kubernetes Networking Best Practices

by Bala

Best practices for Kubernetes networking and service mesh implementation

Kubernetes Networking Best Practices

Implementing proper networking practices in Kubernetes is crucial for security and performance. This guide covers essential networking best practices.

Prerequisites

  • Basic understanding of Kubernetes
  • Access to a Kubernetes cluster
  • kubectl CLI tool installed
  • Familiarity with networking concepts

Project Structure

.
├── networking/
│   ├── network-policies/    # Network policy definitions
│   ├── service-mesh/        # Service mesh configurations
│   ├── ingress/            # Ingress configurations
│   └── services/           # Service definitions
└── monitoring/
    ├── network-metrics/    # Network monitoring configs
    └── alerts/            # Network alert definitions

Network Policies

1. Default Deny Policy

Always start with a default deny policy:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  - Egress

2. Allow Required Traffic

Define specific allow rules:

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

Service Mesh Implementation

1. Istio Configuration

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: service-routes
spec:
  hosts:
  - service-a
  http:
  - route:
    - destination:
        host: service-a
        subset: v1
      weight: 90
    - destination:
        host: service-a
        subset: v2
      weight: 10

2. Traffic Management

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: circuit-breaker
spec:
  host: service-a
  trafficPolicy:
    connectionPool:
      tcp:
        maxConnections: 100
      http:
        http1MaxPendingRequests: 1
    outlierDetection:
      consecutiveErrors: 5
      interval: 30s
      baseEjectionTime: 30s

Ingress Configuration

1. Basic Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: basic-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - http:
      paths:
      - path: /app
        pathType: Prefix
        backend:
          service:
            name: app-service
            port:
              number: 80

2. TLS Configuration

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: tls-ingress
spec:
  tls:
  - hosts:
    - example.com
    secretName: tls-secret
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app-service
            port:
              number: 80

Service Types

1. ClusterIP Service

apiVersion: v1
kind: Service
metadata:
  name: internal-service
spec:
  type: ClusterIP
  selector:
    app: backend
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8080

2. LoadBalancer Service

apiVersion: v1
kind: Service
metadata:
  name: public-service
spec:
  type: LoadBalancer
  selector:
    app: frontend
  ports:
  - protocol: TCP
    port: 80
    targetPort: 3000

Network Monitoring

1. Prometheus Network Metrics

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: network-monitor
spec:
  selector:
    matchLabels:
      app: network-metrics
  endpoints:
  - port: metrics

2. Network Alerts

apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  name: network-alerts
spec:
  groups:
  - name: network
    rules:
    - alert: HighLatency
      expr: network_latency_seconds > 1
      for: 5m
      labels:
        severity: warning

Best Practices Checklist

  1. ✅ Implement Network Policies
  2. ✅ Use Service Mesh for Complex Routing
  3. ✅ Configure Secure Ingress
  4. ✅ Implement TLS Everywhere
  5. ✅ Monitor Network Metrics
  6. ✅ Set Up Network Alerts
  7. ✅ Use Appropriate Service Types
  8. ✅ Implement Circuit Breakers
  9. ✅ Configure Network Segmentation
  10. ✅ Regular Network Audits

Common Networking Pitfalls

  1. ❌ No network policies
  2. ❌ Exposing internal services
  3. ❌ Missing TLS configuration
  4. ❌ Poor service discovery
  5. ❌ Inadequate monitoring

Conclusion

Implementing these networking best practices ensures secure and efficient communication within your Kubernetes clusters. Regular monitoring and updates to networking policies will help maintain optimal performance and security.

Additional Resources