备考ICA----Istio实验2---Istio Gateway 和 VirtualService 实验

1. 部署helloworld app

hellowworld app主要是由一个svc加2个deployment组成

2个deployment都拥有一个app=helloworld的标签,还各自拥有自己版本的version,分别是v1和v2

service通过app=helloworl将流量分发给v1和v2

当两个deployment中pod个数一样时,那么大概会各自获取到50%的流量.当放大或缩小某个deployment中pod数量,可以大致的实现不同比例的流量分发到2个版本上,这也是早期金丝雀的一种用法.

yaml内容如下

yaml 复制代码

apiVersion: v1
kind: Service
metadata:
  name: helloworld
  labels:
    app: helloworld
    service: helloworld
spec:
  ports:
  - port: 5000
    name: http
  selector:
    app: helloworld
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: helloworld-v1
  labels:
    app: helloworld
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: helloworld
      version: v1
  template:
    metadata:
      labels:
        app: helloworld
        version: v1
    spec:
      containers:
      - name: helloworld
        image: docker.io/istio/examples-helloworld-v1
        resources:
          requests:
            cpu: "100m"
        imagePullPolicy: IfNotPresent #Always
        ports:
        - containerPort: 5000
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: helloworld-v2
  labels:
    app: helloworld
    version: v2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: helloworld
      version: v2
  template:
    metadata:
      labels:
        app: helloworld
        version: v2
    spec:
      containers:
      - name: helloworld
        image: docker.io/istio/examples-helloworld-v2
        resources:
          requests:
            cpu: "100m"
        imagePullPolicy: IfNotPresent #Always
        ports:
        - containerPort: 5000

bash 复制代码

kubectl apply -f istio/samples/helloworld/helloworld.yaml

bash 复制代码

kubectl get pods --show-labels |grep helloworld

测试通过访问svc的地址可以看到和我们预期的结果差不多

bash 复制代码

kubectl get svc
for i in {1..20};do curl $(kubectl get svc helloworld|grep helloworld|awk '{print $3}'):5000/hello;sleep 0.5 ;done

2. 发布 Gateway 和 VirtualService

istio/samples/helloworld/helloworld-gateway.yaml

在ingressgateway的80端口监听,当所有hosts的流量匹配uri: /hello如果匹配上那么将所有流量转发给helloworld:5000的endpoint进行响应

yaml 复制代码

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: helloworld-gateway
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: helloworld
spec:
  hosts:
  - "*"
  gateways:
  - helloworld-gateway
  http:
  - match:
    - uri:
        exact: /hello
    route:
    - destination:
        host: helloworld
        port:
          number: 5000

bash 复制代码

kubectl apply -f istio/samples/helloworld/helloworld-gateway.yaml

Gateway和Virtualservice被创建

3. 访问测试

此时可以通过ingressgateway访问到hello的内容,通过刷新可以分别读取到v1和v2

当多次curl时可以看到流量被随机分配到2个版本上

bash 复制代码

for i in {1..20};do curl http://192.168.126.220/hello ;sleep .5 ;done

当访问量足够大时,流量分配趋近于1:1