HTTP Migration Example

This example shows you how to migrate an existing Ingress configuration to the equivalent Gateway API resource.

The Cilium Ingress HTTP Example serves as the starting Ingress configuration. The same approach applies to other controllers, though each Ingress controller configuration varies.

The example Ingress configuration routes traffic to backend services from the bookinfo demo microservices app from the Istio project.

Review Ingress Configuration

You can find the example Ingress definition in basic-ingress.yaml.

# Basic ingress for istio bookinfo demo application, which can be found in below
# https://raw.githubusercontent.com/istio/istio/release-1.11/samples/bookinfo/platform/kube/bookinfo.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: basic-ingress
  namespace: default
spec:
  ingressClassName: cilium
  rules:
  - http:
      paths:
      - backend:
          service:
            name: details
            port:
              number: 9080
        path: /details
        pathType: Prefix
      - backend:
          service:
            name: productpage
            port:
              number: 9080
        path: /
        pathType: Prefix

This example listens for traffic on port 80, routes requests for the path /details to the details service, and / to the productpage service.

Create Equivalent Gateway Configuration

To create the equivalent Gateway configuration, consider the following:

• Entry Point

The entry point is a combination of an IP address and port through which external clients access the data plane.

IngressGateway API

Every Ingress resource has two implicit entry points – one for HTTP and the other for HTTPS traffic. An Ingress controller provides the entry points. Typically, entry points are either shared by all Ingress resources, or every Ingress resource has dedicated entry points.

apiVersion: networking.k8s.io/v1
kind: Ingress
spec:
  ingressClassName: cilium

• Routing Rules

When using Ingress or Gateway API, routing rules must be defined to attach applications to those entry points.

IngressGateway API

The path-based routing rules are configured in the Ingress resource.

In the Ingress resource, each hostname has separate routing rules:

apiVersion: networking.k8s.io/v1
kind: Ingress
[...]
rules:
- http:
    paths:
    - backend:
        service:
          name: details
          port:
            number: 9080
      path: /details
      pathType: Prefix
    - backend:
        service:
          name: productpage
          port:
            number: 9080
      path: /
      pathType: Prefix

• Selecting Data Plane to Attach to:

Both Ingress and Gateway API resources must be explicitly attached to a Dataplane.

IngressGateway API

An Ingress resource must specify a class that selects which Ingress controller to use.

apiVersion: networking.k8s.io/v1
kind: Ingress
spec:
  ingressClassName: cilium

Review Equivalent Gateway Configuration

You can find the equivalent final Gateway and HTTPRoute definition in http-migration.yaml.

---
apiVersion: gateway.networking.k8s.io/v1beta1
kind: Gateway
metadata:
  name: cilium-gateway
  namespace: default
spec:
  gatewayClassName: cilium
  listeners:
  - name: http
    port: 80
    protocol: HTTP
---
apiVersion: gateway.networking.k8s.io/v1beta1
kind: HTTPRoute
metadata:
  name: all-hosts
  namespace: default
spec:
  parentRefs:
  - name: cilium-gateway
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /
    backendRefs:
    - name: productpage
      port: 9080
  - matches:
    - path:
        type: PathPrefix
        value: /details
    backendRefs:
    - name: details
      port: 9080

The preceding example creates a Gateway named cilium-gateway that listens on port 80 for HTTP traffic. Two routes are defined, one for /details to the details service, and one for / to the productpage service.

Deploy the resources and verify that the HTTP requests are routed successfully to the services. For more information, consult the Gateway API HTTP Example.