官方文档：Istio / 流量转移

前提条件：

  • 微服务使用deployment+service部署到集群

1、配置命名空间自动注入sidecar

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kubectl label namespace default istio-injection=enabled

我这里使用istio官方提供的bookinfo程序演示

2、部署bookinfo示例程序

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cat > bookinfo.yaml << EOF
apiVersion: v1
kind: Service
metadata:
  name: details
  labels:
    app: details
    service: details
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: details
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-details
  labels:
    account: details
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: details-v1
  labels:
    app: details
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: details
      version: v1
  template:
    metadata:
      labels:
        app: details
        version: v1
    spec:
      serviceAccountName: bookinfo-details
      containers:
      - name: details
        image: docker.io/istio/examples-bookinfo-details-v1:1.18.0
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
---
apiVersion: v1
kind: Service
metadata:
  name: ratings
  labels:
    app: ratings
    service: ratings
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: ratings
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-ratings
  labels:
    account: ratings
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ratings-v1
  labels:
    app: ratings
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ratings
      version: v1
  template:
    metadata:
      labels:
        app: ratings
        version: v1
    spec:
      serviceAccountName: bookinfo-ratings
      containers:
      - name: ratings
        image: docker.io/istio/examples-bookinfo-ratings-v1:1.18.0
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
---
apiVersion: v1
kind: Service
metadata:
  name: reviews
  labels:
    app: reviews
    service: reviews
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: reviews
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-reviews
  labels:
    account: reviews
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: reviews-v1
  labels:
    app: reviews
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: reviews
      version: v1
  template:
    metadata:
      labels:
        app: reviews
        version: v1
    spec:
      serviceAccountName: bookinfo-reviews
      containers:
      - name: reviews
        image: docker.io/istio/examples-bookinfo-reviews-v1:1.18.0
        imagePullPolicy: IfNotPresent
        env:
        - name: LOG_DIR
          value: "/tmp/logs"
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
        - name: wlp-output
          mountPath: /opt/ibm/wlp/output
      volumes:
      - name: wlp-output
        emptyDir: {}
      - name: tmp
        emptyDir: {}
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: reviews-v2
  labels:
    app: reviews
    version: v2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: reviews
      version: v2
  template:
    metadata:
      labels:
        app: reviews
        version: v2
    spec:
      serviceAccountName: bookinfo-reviews
      containers:
      - name: reviews
        image: docker.io/istio/examples-bookinfo-reviews-v2:1.18.0
        imagePullPolicy: IfNotPresent
        env:
        - name: LOG_DIR
          value: "/tmp/logs"
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
        - name: wlp-output
          mountPath: /opt/ibm/wlp/output
      volumes:
      - name: wlp-output
        emptyDir: {}
      - name: tmp
        emptyDir: {}
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: reviews-v3
  labels:
    app: reviews
    version: v3
spec:
  replicas: 1
  selector:
    matchLabels:
      app: reviews
      version: v3
  template:
    metadata:
      labels:
        app: reviews
        version: v3
    spec:
      serviceAccountName: bookinfo-reviews
      containers:
      - name: reviews
        image: docker.io/istio/examples-bookinfo-reviews-v3:1.18.0
        imagePullPolicy: IfNotPresent
        env:
        - name: LOG_DIR
          value: "/tmp/logs"
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
        - name: wlp-output
          mountPath: /opt/ibm/wlp/output
      volumes:
      - name: wlp-output
        emptyDir: {}
      - name: tmp
        emptyDir: {}
---
apiVersion: v1
kind: Service
metadata:
  name: productpage
  labels:
    app: productpage
    service: productpage
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: productpage
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-productpage
  labels:
    account: productpage
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: productpage-v1
  labels:
    app: productpage
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: productpage
      version: v1
  template:
    metadata:
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9080"
        prometheus.io/path: "/metrics"
      labels:
        app: productpage
        version: v1
    spec:
      serviceAccountName: bookinfo-productpage
      containers:
      - name: productpage
        image: docker.io/istio/examples-bookinfo-productpage-v1:1.18.0
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
      volumes:
      - name: tmp
        emptyDir: {}
EOF
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kubectl apply -f bookinfo.yaml

所有pod运行时2/2即为部署成功，sidecar也以容器形式注入到pod内。

3、部署网关

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cat > bookinfo-gateway.yaml << EOF
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: bookinfo-gateway
spec:
  # The selector matches the ingress gateway pod labels.
  # If you installed Istio using Helm following the standard documentation, this would be "istio=ingress"
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 8080
      name: http
      protocol: HTTP
    hosts:
    # 允许所有域名通过gateway
    - "*"
EOF
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kubectl apply -f bookinfo-gateway.yaml

4、部署前端virtual service

这里的前端指的时发送请求的服务，可以是中间件也可以是后端的接口，我这里使用productpage服务

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cat > virtual-service-productpage.yaml << EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: bookinfo
spec:
  hosts:
  # 访问时服务使用的域名，*表示允许所有访问
  - "*"
  # 外部访问时需要指定gateways，选择入口网关
  gateways:
  - bookinfo-gateway
  http:
  # 匹配规则
  - match:
    - uri:
        # uri 完全 匹配时走下面路由
        exact: /productpage
    - uri:
        # uri 前缀 匹配时走下面路由
        prefix: /static
    - uri:
        exact: /login
    - uri:
        exact: /logout
    - uri:
        prefix: /api/v1/products
    route:
    # 目标路由
    - destination:
        # service名称
        host: productpage
        # service端口
        port:
          number: 9080
EOF
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kubectl apply -f virtual-service-productpage.yaml

5、访问

通过istio-ingress服务的外部IP访问http://10.20.12.190/productpage，如果没有部署MetalLB可以使用nodeIP+30271（istio-ingress服务80端口的映射端口）访问http://10.20.12.10:30271/productpage

访问后刷新页面，发现reviews服务时每次刷新都会请求不同的版本，这是因为后端服务还没有被纳管，此时的请求是通过productpage请求reviews服务的service返回的

6、创建目标规则

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cat > destination-rule-all.yaml << EOF
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: productpage
spec:
  host: productpage
  subsets:
  - name: v1
    labels:
      version: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v3
    labels:
      version: v3
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: ratings
spec:
  host: ratings
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v2-mysql
    labels:
      version: v2-mysql
  - name: v2-mysql-vm
    labels:
      version: v2-mysql-vm
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: details
spec:
  host: details
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
EOF
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kubectl apply -f destination-rule-all.yaml

此时将所有服务都设置了规则，按照pod label为version 的识别出来，这一步并不会对请求发生变化，这是为了方便后面调整变化时使用的。

7、创建后端virtual service

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cat > virtual-service-all-v1.yaml <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: productpage
spec:
  hosts:
  - productpage
  http:
  - route:
    - destination:
        host: productpage
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings
spec:
  hosts:
  - ratings
  http:
  - route:
    - destination:
        host: ratings
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: details
spec:
  hosts:
  - details
  http:
  - route:
    - destination:
        host: details
        subset: v1
EOF
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kubectl apply -f virtual-service-all-v1.yaml

此时后端服务都被istio纳管，并将路由目标指向v1版本，现在不管怎么请求，reviews服务都是v1版本

8、灰度发布

之前的操作都是为了能模拟一个正常使用的业务，并将服务通过istio的virtual service管理，接下来才是灰度发布的操作

要升级Review服务从v1到v2版本，首先部署这个deployment，这个demo中已经部署了，并且之前访问时也看到了

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cat > virtual-service-reviews.yaml << EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
      weight: 80
    - destination:
        host: reviews
        subset: v2
      weight: 20
EOF
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kubectl apply -f virtual-service-reviews.yaml

再次刷新页面模拟请求，发现80%的流量在v1，20%流量分配到v2

在kiali中也可以看到流量分配情况

运行一段时间再次调整v2流量的比例直到100%流量到v2，这时可以下线v1版本。