Explain Kubernetes Ingress controllers and how they differ from LoadBalancer services.

Ingress controllers provide HTTP/HTTPS routing and load balancing at the application layer, offering more advanced features than LoadBalancer services.\n\nIngress vs LoadBalancer:\n• Ingress: Layer 7 (HTTP/HTTPS) routing\n• LoadBalancer: Layer 4 (TCP/UDP) load balancing\n• Ingress: Single entry point for multiple services\n• LoadBalancer: One external IP per service\n\nIngress Features:\n• Host-based routing (virtual hosting)\n• Path-based routing\n• SSL/TLS termination\n• URL rewriting and redirects\n• Authentication and authorization\n• Rate limiting and traffic shaping\n\nIngress Components:\n• Ingress Resource: Routing rules definition\n• Ingress Controller: Implementation (NGINX, Traefik, HAProxy)\n• Ingress Class: Controller selection\n\nExample Ingress:\napiVersion: networking.k8s.io/v1\nkind: Ingress\nmetadata:\n name: web-ingress\n annotations:\n nginx.ingress.kubernetes.io/rewrite-target: /\n cert-manager.io/cluster-issuer: letsencrypt\nspec:\n ingressClassName: nginx\n tls:\n - hosts:\n - api.example.com\n secretName: api-tls\n rules:\n - host: api.example.com\n http:\n paths:\n - path: /api/v1\n pathType: Prefix\n backend:\n service:\n name: api-service\n port:\n number: 80\n\nPopular Controllers:\n• NGINX Ingress: Most popular, feature-rich\n• Traefik: Cloud-native, automatic service discovery\n• HAProxy: High performance, enterprise features\n• Istio Gateway: Service mesh integration\n• AWS ALB: Native AWS integration\n\nBest Practices:\n• Use cert-manager for automatic SSL certificates\n• Implement rate limiting and security headers\n• Monitor ingress controller performance\n• Use multiple ingress controllers for different needs\n• Configure proper health checks