Confused about Serving and using Ingress

[johnmanko]

I'm pretty confused about routing traffic to a function. I just don't understand what's going on here.

I want to manage routing using the Gateway API and HttpRoute resources, just like I do with standard k8s Service resources for microservices. Is that possible?

So, given an existing Gateway (running Istio, btw), I'd like to add the following HttpRoute:

apiVersion: v1
kind: Namespace
metadata:
  name: ingress
---
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: gateway
  namespace: ingress
spec:
  gatewayClassName: istio
  listeners:
  - name: http-listener
    port: 80
    protocol: HTTP
    allowedRoutes:
      namespaces:
        from: All
  - name: https-listener
    port: 443
    protocol: TLS
    tls:
      mode: Passthrough      
    allowedRoutes:
      namespaces:
        from: All

Then the HttpRoute would be something like:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: kn-hello-route
  namespace: saas-app
spec:
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: gateway
    namespace: ingress
  rules:
  - backendRefs:
    - group: ""
      kind: Service
      name: kn-hello-service
      namespace: saas-app
      port: 80
      weight: 1
    matches:
    - path:
        type: PathPrefix
        value: /
    filters:
    - type: URLRewrite
      urlRewrite:
        path:
          type: ReplacePrefixMatch
          replacePrefixMatch: /api/v1/hello

Assuming the following Knative Service:

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: kn-hello-service
  namespace: saas-app
spec:
  template:
    spec:
      containers:
        - image: ghcr.io/knative/helloworld-go:latest
          ports:
            - containerPort: 8080
          env:
            - name: TARGET
              value: "World"

Is that possible? It's confusing, because according to the docs Knative Ingress creates subdomains for functions.

kn service create hello \
--image ghcr.io/knative/helloworld-go:latest \
--port 8080 \
--env TARGET=World

Which would be accessed via http://hello.default.${LOADBALANCER_IP}.sslip.io.

If using the operator for managing Serving, would the following be correct?

apiVersion: v1
kind: Namespace
metadata:
  name: knative-serving
---
apiVersion: operator.knative.dev/v1beta1
kind: KnativeServing
metadata:
  name: knative-serving
  namespace: knative-serving
spec:
  ingress:
    istio:
      enabled: true
      knative-ingress-gateway:
        selector:
          istio: ingressgateway
  config:
    istio:
      external-gateways: |
        - name: gateway
          namespace: ingress
          service: gateway-istio.ingress.svc.cluster.local

[dprotaso]

I believe this was answered in slack here - https://cloud-native.slack.com/archives/C04LMU0AX60/p1736451011275479