Access in-mesh gRPC services via an ASM gateway - Alibaba Cloud Service Mesh

Use an ASM ingress gateway to securely access gRPC services within your mesh. This enables precise access control, improved service governance, and secure service-to-service communication. This topic shows how to access a gRPC service through an ingress gateway and shift traffic between two versions of the service.

Before you begin

Step 1: Deploy the sample application

Deploy two versions of a sample application: istio-grpc-server-v1 and istio-grpc-server-v2.

Create a file named app.yaml.

YAML

apiVersion: apps/v1
kind: Deployment
metadata:
  name: grpc-helloworld-py-v1
  labels:
    app: grpc-helloworld-py
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: grpc-helloworld-py
      version: v1
  template:
    metadata:
      labels:
        app: grpc-helloworld-py
        version: v1
    spec:
      containers:
        - name: grpc-helloworld-py
          image: registry.cn-hangzhou.aliyuncs.com/aliacs-app-catalog/istio-grpc-server:grpc-helloworld-py-v1.0
          imagePullPolicy: Always
          env:
            - name: podname
              valueFrom:
                fieldRef:
                  apiVersion: v1
                  fieldPath: metadata.name
          ports:
            - containerPort: 50051
              name: grpc-port
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: grpc-helloworld-py-v2
  labels:
    app: grpc-helloworld-py
    version: v2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: grpc-helloworld-py
      version: v2
  template:
    metadata:
      labels:
        app: grpc-helloworld-py
        version: v2
    spec:
      containers:
        - name: grpc-helloworld-py
          image: registry.cn-hangzhou.aliyuncs.com/aliacs-app-catalog/istio-grpc-server:grpc-helloworld-py-v1.0
          imagePullPolicy: Always
          env:
            - name: podname
              valueFrom:
                fieldRef:
                  apiVersion: v1
                  fieldPath: metadata.name
          ports:
            - containerPort: 50051
              name: grpc-port
---
apiVersion: v1
kind: Service
metadata:
  name: grpc-helloworld-py
  labels:
    app: grpc-helloworld-py
spec:
  ports:
    - port: 50051
      name: grpc-port
  selector:
    app: grpc-helloworld-py

Deploy the application.
```
kubectl apply -f app.yaml
```

Step 2: Set the routing rules

Create a gateway, a virtual service, and a destination rule to route all traffic to the istio-grpc-server-v1 service.

Create a file named rules.yaml.

apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: grpc-gateway
spec:
  selector:
    istio: ingressgateway
  servers:
  - port:
      number: 8080
      name: grpc
      protocol: GRPC
    hosts:
    - "*"
---
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: dr-istio-grpc-server
spec:
  host: grpc-helloworld-py
  trafficPolicy:
    loadBalancer:
      simple: ROUND_ROBIN
  subsets:
    - name: v1
      labels:
        version: "v1"
    - name: v2
      labels:
        version: "v2"    
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: grpc-vs
spec:
  hosts:
  - "*"
  gateways:
  - grpc-gateway
  http:
    - match:
        - port: 8080
      route:
        - destination:
            host: grpc-helloworld-py
            port:
              number: 50051
            subset: v1
          weight: 100
        - destination:
            host: grpc-helloworld-py
            port:
              number: 50051
            subset: v2
          weight: 0

Apply the rules.
```
kubectl apply -f rules.yaml
```

Step 3: Deploy or use an ingress gateway

New gateway

Create an ingress gateway and add port 8080 during the Port Mapping configuration.

Existing gateway

Log on to the ASM console. In the left-side navigation pane, choose Service Mesh > Mesh Management.
On the Mesh Management page, click the name of the ASM instance. In the left-side navigation pane, choose ASM Gateways > Ingress Gateway.
On the Ingress Gateway page, click the name of the target gateway. On the Gateway Details page, in the Basic options section, click the icon next to Port. In the Port Mapping dialog box, click Add Port, set Protocol to TCP and Service Port to 8080, and then click Submit.

Step 4: Run the gRPC client

Install the grpcurl command-line tool and run the following command:

grpcurl -d '{"name": "Jack"}' -plaintext {IP address of the ingress gateway}:8080 helloworld.Greeter/SayHello

The output shows that all requests are routed to v1.

 "message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
 "message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
 "message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
 "message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
 "message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"

Step 5: Shift traffic with weighted routing

Update the virtual service to route 40% of the traffic to v2 and the remaining 60% to v1.

Edit the virtual service.

kubectl edit VirtualService grpc-vs

Modify the route section as follows and save the changes.

....
      route:
        - destination:
            host: grpc-helloworld-py
            port:
              number: 50051
            subset: v1
          weight: 60
        - destination:
            host: grpc-helloworld-py
            port:
              number: 50051
            subset: v2
          weight: 40

Run the grpcurl command again to access the gRPC service in the mesh.

grpcurl -d '{"name": "Jack"}' -plaintext {IP address of the ingress gateway}:8080 helloworld.Greeter/SayHello

The output shows that approximately 40% of the traffic is routed to v2.

Note

Your results may not show an exact 40/60 split, but the overall traffic distribution will approach this ratio over time.

"message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v2-7f56b49b7f-9vvr7!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v2-7f56b49b7f-9vvr7!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v2-7f56b49b7f-9vvr7!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v2-7f56b49b7f-9vvr7!"
"message": "Hello, Jack! I'm from grpc-helloworld-py-v1-79b5dc9654-cg4dq!"