How to Configure Ingress in GKE on Google Cloud Platform

To configure Ingress in GKE, first create a Kubernetes Ingress resource that defines rules for routing external HTTP(S) traffic to your services. Then, ensure your GKE cluster has an Ingress controller like the default GCP HTTP(S) Load Balancer enabled to manage the traffic flow.

Syntax

An Ingress resource in GKE is a YAML file that defines how external traffic is routed to your Kubernetes services. It includes:

• apiVersion: The Kubernetes API version, usually networking.k8s.io/v1.
• kind: Always Ingress for this resource.
• metadata: Name and annotations for the Ingress.
• spec: Rules that map hostnames and paths to backend services.

yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  annotations:
    kubernetes.io/ingress.class: "gce"
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /path
        pathType: Prefix
        backend:
          service:
            name: example-service
            port:
              number: 80

Example

This example shows a complete Ingress configuration that routes traffic from myapp.example.com to a service named myapp-service on port 8080. It uses the GCP Ingress controller.

yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
  annotations:
    kubernetes.io/ingress.class: "gce"
spec:
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 8080

Output

ingress.networking.k8s.io/myapp-ingress created

Common Pitfalls

Common mistakes when configuring Ingress in GKE include:

• Not specifying the correct ingress.class annotation, which tells GKE which controller to use.
• Using incorrect service names or ports in the backend, causing routing failures.
• Forgetting to expose the service with a Service of type NodePort or ClusterIP that matches the Ingress backend.
• Not having the GKE Ingress controller enabled or misconfigured cluster permissions.

Example of a wrong annotation and the fix:

yaml

# Wrong: missing ingress class annotation
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: bad-ingress
spec:
  rules:
  - http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-service
            port:
              number: 80

# Right: specify GCE ingress class
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: good-ingress
  annotations:
    kubernetes.io/ingress.class: "gce"
spec:
  rules:
  - http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-service
            port:
              number: 80

Quick Reference

Tips for configuring Ingress in GKE:

• Always use kubernetes.io/ingress.class: "gce" annotation for GCP Ingress controller.
• Ensure your backend services are correctly exposed and reachable.
• Use kubectl describe ingress [name] to debug issues.
• Check GCP Console for Load Balancer status created by Ingress.

Key Takeaways

Create a Kubernetes Ingress resource with rules to route external traffic to services.

Use the annotation kubernetes.io/ingress.class: "gce" to enable GCP's Ingress controller.

Make sure backend services exist and expose the correct ports.

Check Ingress status and GCP Load Balancer to verify configuration.

Common errors include missing ingress class and incorrect service references.