操作场景

在预发布过程中，为了尽可能使新版本服务的流量与线上保持一致，且不对线上环境产生影响，可以将线上流量镜像到预发布版本。同时通过流量镜像功能也可以对线上流量进行采集分析。

部署服务

部署 v1 和 v2 版本的 deployment以及对应的service 至集群

apiVersion: apps/v1
kind: Deployment
metadata:
  name: product-v2
  namespace: base
  labels:
    app: product
    version: v2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: product
      version: v2
  template:
    metadata:
      labels:
        app: product
        version: v2
    spec:
      containers:
        - name: product
          image: nginx:1.25-alpine
          ports:
            - containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: product-v1
  namespace: base
spec:
  replicas: 1
  selector:
    matchLabels:
      app: product
      version: v1
  template:
    metadata:
      labels:
        app: product
        version: v1
    spec:
      containers:
        - name: product
          image: nginx:1.25-alpine
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: product
  name: product
  namespace: base
spec:
  ports:
  - name: http
    port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: product
  type: ClusterIP

应用服务网格配置

假设v1为线上版本，v2为预发布版本，通过DestinationRule定义subset v1和v2，同时在VirtualService中对流量镜像的策略进行定义，将线上流量复制到预发布版本。将以下yaml配置部署至集群：

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: product-vs
  namespace: base
spec:
  gateways:
  - mesh
  hosts:
  - product
  http:
  - route:
    - destination:
        host: product
        port:
          number: 80
        subset: v1
    mirror:
      host: product      
      subset: v2        
      port:              
        number: 80
    mirrorPercentage:    # 可选，默认100.0
      value: 50.0
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: product
  namespace: base
spec:
  host: product
  subsets:
    - name: v1
      labels:
        version: v1
    - name: v2
      labels:
        version: v2

上述配置实现了将v1流量的50%镜像到v2。