Istio学习之CRD1⃣️：VirtualService

Istio的自定义资源有五十多个，今天先对Network部分的VirtualService的学习做个记录。

介绍

  1. 首先献上官方文档：https://istio.io/latest/zh/docs/reference/config/networking/virtual-service/

  2. VirtualService主要是定义了服务的路由规则，如果流量满足了我们设定的匹配规则，则会根据我们的设定将流量发送到服务注册表中的服务/版本

  3. 样例

    apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews-route
spec:
    # host为必要字段，表示目标主机，尽量使用FQDN来进行服务引用，同个命名空间可以使用服务的短名称
  hosts:
  - reviews.prod.svc.cluster.local
  # HTTP的有序路由规则列表，对httpx，http2x，grpc，都是有效的，匹配规则从上往下
  http:
  - name: "reviews-v2-routes"
      # 匹配规则，有根据uri，header，host，port，queryParams，scheme等
      # 匹配规则有：exact精准匹配，prefix前缀匹配，regex正则匹配
    match:
    - uri:
        exact: "/wpcatalog"
    - uri:
        prefix: "/consumercatalog"
    # 重写HTTP URI和Authority标头。重写将在转发之前执行。
    rewrite:
      uri: "/newcatalog"
    # 重定向，重定向不能与重写一起使用
    redirect:
      uri: /v1/bookRatings
      authority: newratings.default.svc.cluster.local
    route:
    - destination:
        host: reviews.prod.svc.cluster.local
        subset: v2
      # 权重
      weight: 80
  - name: "reviews-v1-route"
    route:
    - destination:
        host: reviews.prod.svc.cluster.local
        subset: v1
    # cors
    corsPolicy:
      allowOrigin:
      - example.com
      allowMethods:
      - POST
      - GET
      allowCredentials: false
      allowHeaders:
      - X-Foo-Bar
      maxAge: "24h"

  # 应用到路由的网关，忽略默认使用默认网关
  gateways:
  - mygateway

  # 透传TLS和HTTPS的流量的路由规则列表
  tls:
  - match:
    - port: 443
      sniHosts:
      - login.bookinfo.com
    route:
    - destination:
        host: login.prod.svc.cluster.local  

  # 透传tcp流量的有序路由规则列表，对所有HTTP和TLS之外的端口生效      
  tcp:
  - match:
    - port: 27017
    route:
    - destination:
        host: mongo.backup.svc.cluster.local
        port:
          number: 5555

演示

创建两个对应的http server

  1. httpd：

    apiVersion: apps/v1
kind: Deployment
metadata:
  name: httpd
  labels:
    server: httpd
    app: web
spec:
  replicas: 1
  selector:
    matchLabels:
      server: httpd
      app: web
  template:
    metadata:
      labels:
        server: httpd
        app: web
    spec:
      containers:
      - name: busybox
        image: busybox
        imagePullPolicy: IfNotPresent
        command: ["/bin/sh", "-c", "echo 'this is httpd' > /var/www/index.html; httpd -f -p 8080 -h /var/www"]

---
apiVersion: v1
kind: Service
metadata:
  name: httpd-svc
spec:
  selector:
    server: httpd
  ports:
  - name: http
    port: 8080
    targetPort: 8080
    protocol: TCP

  2. tomcat

    apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat
  labels:
    server： tomcat
    app: web
spec:
  replicas: 1
  selector:
    matchLabels:
      server: tomcat
      app: web
  template:
    metadata:
      labels:
        server: tomcat
        app: web
    spec:
      containers:
      - name: tomcat
        image: docker.io/kubeguide/tomcat-app:v1
        imagePullPolicy: IfNotPresent

--- 
apiVersion: v1
kind: Service
metadata:
  name: tomcat-svc
spec:
  selector:
    server: tomcat
  ports:
  - name: http
    port: 8080
    targetPort: 8080
    protocol: TCP

  3. Busy box进入容器中测试 ```yaml apiVersion: apps/v1 kind: Deployment metadata: name: hexiaohong-client spec: replicas: 1 selector:

    matchLabels:
  app: hexiaohong-client

    template:

    metadata:
  labels:
    app: hexiaohong-client
spec:
  containers:
  - name: busybox
    image: busybox
    imagePullPolicy: IfNotPresent
    command: ["/bin/sh", "-c", "sleep 3600"]

apiVersion: v1 kind: Service metadata: name: web-svc spec: selector: app: hexiaohong-client ports:

 - name: http
   port: 8080
   targetPort: 8080
   protocol: TCP



### 进入busybox测试

1. httpd
![在这里插入图片描述](http://cd7.yesapi.net/89E670FD80BA98E7F7D7E81688123F32_20210325235333_dd5afe6e7d3ed76a63272e9608b35254.png)


2. tomcat
![在这里插入图片描述](http://cd7.yesapi.net/89E670FD80BA98E7F7D7E81688123F32_20210325235443_6f227be075b7fef2dfecb3842a4e87b9.png)






### 创建VirtualService实现流控

1. 创建VirtualService

   ```yaml
   apiVersion: networking.istio.io/v1alpha3
   kind: VirtualService
   metadata:
     name: web-svc-vs
   spec:
     hosts:
     - web-svc.default.svc.cluster.local
     http:
     - route:
       - destination:
           host: httpd-svc
         weight: 80
       - destination:
           host: tomcat-svc
         weight: 20
  1. 查看VirtualService：
   # kubectl get virtualservices.networking.istio.io

   NAME         GATEWAYS               HOSTS                                   AGE
   bookinfo     ["bookinfo-gateway"]   ["*"]                                   31h
   web-svc-vs                          ["web-svc.default.svc.cluster.local"]   43s
  1. 80%流量到httpd，20%到tomcat 在这里插入图片描述

创建VirtualService实现路由

  1. 创建带匹配条件的VirtualService

    apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: web-svc-vs
spec:
hosts:
- web-svc.default.svc.cluster.local
http:
- match:
   - headers:
         to:
             exact: httpd
   route:
 - destination:
     host: httpd-svc
- route:
 - destination:
     host: tomcat-svc
  1. 携带header:'to: httpd'将流量导入httpd，否则则到tomcat 在这里插入图片描述

样例来自学习九析大佬的教程

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