Hello, HTTP

Expose a web application through your first Gateway and HTTPRoute.

Use case: you have a web application in the cluster and want to reach it from outside.

1. Deploy something to route to

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello
spec:
  replicas: 2
  selector:
    matchLabels:
      app: hello
  template:
    metadata:
      labels:
        app: hello
    spec:
      containers:
        - name: hello
          image: ghcr.io/mendhak/http-https-echo:37
          ports:
            - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: hello
spec:
  selector:
    app: hello
  ports:
    - port: 80
      targetPort: 8080

2. Create a Gateway

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: edge
spec:
  gatewayClassName: krouter
  listeners:
    - name: http
      protocol: HTTP
      port: 80
      allowedRoutes:
        namespaces:
          from: Same

krouter generates a NodePort Service for it and reports the address in status.addresses:

kubectl get gateway edge -o wide

3. Attach an HTTPRoute

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: hello
spec:
  parentRefs:
    - name: edge
  hostnames:
    - hello.example.com
  rules:
    - matches:
        - path:
            type: PathPrefix
            value: /
      backendRefs:
        - name: hello
          port: 80

4. Test it

GW_IP=$(kubectl get gateway edge -o jsonpath='{.status.addresses[0].value}')
curl -H 'Host: hello.example.com' "http://$GW_IP/"

Run it a few times: responses alternate between the two pods (that is the round-robin balancing across ready EndpointSlice endpoints).

Check what krouter reported back:

kubectl describe httproute hello   # Accepted / ResolvedRefs conditions

Next: serve it over HTTPS.