Gateway API

Gateway API is a Kubernetes API for defining and managing network gateways and their associated routing rules. It provides a declarative way to define how traffic should be routed to services within a Kubernetes cluster, making it easier to manage complex network topologies and improve the scalability and reliability of applications. It obsoletes Ingress.

Exposing HTTP services

Create HTTPRoute to expose HTTP services.

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: my-service-route
spec:
  hostnames:
  - my-service-name.nrp-nautilus.io
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: ingress
    namespace: haproxy
    sectionName: https
  rules:
  - backendRefs:
    - group: ""
      kind: Service
      name: service-name
      port: 8443
      weight: 1
    matches:
    - path:
        type: PathPrefix
        value: /

Replace:

.metadata.name - any name unique within the namespace
.spec.hostnames[0] - the hostname for the HTTP service. Choose any unique one within .nrp-nautilus.io.
.spec.rules[0].backendRefs[0].name - the name of the service in the namespace where it is deployed.
.spec.rules[0].backendRefs[0].port - the port of the service in the namespace where it is deployed.

Use the official docs / reference spec for other fields.

Exposing GRPC services

Create GRPCRoute to expose GRPC services.

apiVersion: gateway.networking.k8s.io/v1
kind: GRPCRoute
metadata:
  name: my-service-route
spec:
  hostnames:
  - my-service-name.nrp-nautilus.io
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: ingress
    namespace: haproxy
    sectionName: grpc
  rules:
  - backendRefs:
    - kind: Service
      name: service-name
      port: 50051
      weight: 1

Replace:

.metadata.name - any name unique within the namespace
.spec.hostnames[0] - the hostname for the GRPC service. Choose any unique one within .nrp-nautilus.io.
.spec.rules[0].backendRefs[0].name - the name of the service in the namespace where it is deployed.
.spec.rules[0].backendRefs[0].port - the port of the service in the namespace where it is deployed.

Use the official docs / reference spec for other fields.

Testing

Testing GRPC

(Taken from envoy gateway docs)

Deploy the test app:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: yages
    example: grpc-routing
  name: yages
spec:
  selector:
    matchLabels:
      app: yages
  replicas: 1
  template:
    metadata:
      labels:
        app: yages
    spec:
      containers:
        - name: grpcsrv
          image: ghcr.io/projectcontour/yages:v0.1.0
          resources:
            limits:
              cpu: 100m
              memory: 100Mi
            requests:
              cpu: 50m
              memory: 50Mi
          ports:
            - containerPort: 9000
              protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: yages
    example: grpc-routing
  name: yages
spec:
  type: ClusterIP
  ports:
    - name: http
      port: 9000
      protocol: TCP
      targetPort: 9000
  selector:
    app: yages
---
apiVersion: gateway.networking.k8s.io/v1
kind: GRPCRoute
metadata:
  name: yages
  labels:
    example: grpc-routing
spec:
  hostnames:
  - test-service.nrp-nautilus.io
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: ingress
    namespace: haproxy
    sectionName: grpc
  rules:
  - backendRefs:
    - kind: Service
      name: yages
      port: 9000
      weight: 1

Check the status of GRPCRoute:

kubectl get grpcroutes --selector=example=grpc-routing -o yaml

The status for the GRPCRoute should surface “Accepted=True” and a parentRef that references the example Gateway. The yages route matches any traffic for “test-service.nrp-nautilus.io” and forwards it to the “yages” Service.

Test GRPC routing to the yages backend using the grpcurl command.

grpcurl test-service.nrp-nautilus.io:50051 yages.Echo/Ping

You should see the below response

{
  "text": "pong"
}

Envoy Gateway also supports gRPC-Web requests for this configuration. The below curl command can be used to send a grpc-Web request with over HTTP/2. You should receive the same response seen in the previous command.

The data in the body AAAAAAA= is a base64 encoded representation of an empty message (data length 0) that the Ping RPC accepts.

curl -s https://test-service.nrp-nautilus.io:50051/yages.Echo/Ping -H 'Content-Type: application/grpc-web-text' -H 'Accept: application/grpc-web-text' -XPOST -d'AAAAAAA=' | base64 -d

This work was supported in part by National Science Foundation (NSF) awards CNS-1730158, ACI-1540112, ACI-1541349, OAC-1826967, OAC-2112167, CNS-2100237, CNS-2120019.