Kubernetes Networking [Level-5: Ingress/Gateway]

This is Level 5 of our Kubernetes networking series. So far, we've built up a solid foundation: LEVEL 1 — Pod networking LEVEL 2 — Pod-to-Pod communication LEVEL 3 — Service (a stable internal endpoint) LEVEL 4 — DNS (service name → Service IP) But we still have a glaring gap: how does a real user on the internet actually reach your Kubernetes application? That's exactly what this article covers — Ingress, Ingress Controllers, and the newer Gateway API. Table of Contents The Problem: The Internet Can't Reach a ClusterIP The Basic Solution: Ingress and Gateway API What Is Ingress? A Routing Example Ingress Is Not the Actual Proxy A Simple Analogy: Traffic Police A Basic Ingress YAML Example Breaking Down the Key Fields Host-Based Routing Path-Based Routing Why Not Just Use a LoadBalancer Service for Everything? The Complete Traffic Flow Where Does DNS Fit In? The Ingress Controller A Typical Architecture Ingress vs Service Ingress vs LoadBalancer Service HTTPS and TLS Termination Why Terminate TLS at the Edge? Referencing a TLS Certificate Routing Multiple Domains The Gateway API GatewayClass, Gateway, and HTTPRoute Ingress vs Gateway API Important Distinctions: Ingress Is Not CNI or Service Troubleshooting Ingress Layer by Layer Common Ingress Mistakes The Complete Kubernetes Networking Picture (Levels 1–5) The Mental Model to Memorize Level 5 Checkpoint What's Next: NetworkPolicy The Problem: The Internet Can't Reach a ClusterIP Suppose you want users to reach your application at myapp.example.com . Inside your cluster, you have: Service : frontend ClusterIP : 10.96.20.10 frontend Service ├── Pod 1 ├── Pod 2 └── Pod 3 A user on the internet can't simply visit http://10.96.20.10 — that's a private Kubernetes Service IP, invisible outside the cluster. We need something sitting at the edge of the cluster to bridge that gap. The Basic Solution: Ingress and Gateway API Historically, Kubernetes solved this with Ingress . More recently, Kubernetes introduced a more expres