Ingress & Load Balancing

🎯 Learning Objectives

• Master Ingress controllers and configuration
• Understand load balancing strategies
• Learn advanced Ingress patterns
• Troubleshoot Ingress and load balancer issues
• Optimize traffic routing and performance

Ingress provides external access to services. Understanding Ingress controllers and load balancing is essential for production deployments.

Ingress Controllers

Popular controllers: NGINX, Traefik, HAProxy, Istio Gateway. Choose based on features and requirements.

SSL/TLS

Always use TLS for production Ingress. Configure certificate management properly.

Ingress Basics

Basic Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: web-service
            port:
              number: 80

TLS Ingress

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: web-service
            port:
              number: 80

Certificate Management

Use cert-manager for automatic certificate provisioning and renewal.

Advanced Patterns

Path-based Routing

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: path-based
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /api
        pathType: Prefix
        backend:
          service:
            name: api-service
            port:
              number: 8080
      - path: /web
        pathType: Prefix
        backend:
          service:
            name: web-service
            port:
              number: 80

Load Balancing

apiVersion: v1
kind: Service
metadata:
  name: web-service
spec:
  type: LoadBalancer
  sessionAffinity: ClientIP
  sessionAffinityConfig:
    clientIP:
      timeoutSeconds: 10800
  ports:
  - port: 80
    targetPort: 8080
  selector:
    app: web

Session Affinity

Use session affinity for stateful applications. Balance with horizontal scaling needs.

Troubleshooting

Common Issues

Ingress Not Working

# Check Ingress status
kubectl get ingress

# Check Ingress controller
kubectl get pods -n ingress-nginx

# Check Ingress controller logs
kubectl logs -n ingress-nginx <controller-pod>

# Test connectivity
curl -H "Host: example.com" http://<ingress-ip>

Troubleshooting Steps

1. Verify Ingress resource exists
2. Check Ingress controller is running
3. Verify service endpoints
4. Check DNS resolution
5. Test with curl/wget

Best Practices

Production Recommendations

1. Use TLS for all Ingress
2. Implement rate limiting
3. Monitor Ingress metrics
4. Use appropriate path types
5. Configure health checks
6. Document routing rules

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