6. Ingress控制进入网格的请求

1. Ingress的基本概念

服务的访问入口，接收外部请求并转发到后端服务。在Istio里Ingress也是一个网关，是通过gateway这个方式去实现的。

2. 实验：创建Ingress网关

引入一个新服务httpbin，同时把服务通过Ingress暴露给外部使其可以访问

1. 部署httpbin服务

官方提供了配置清单，在安装目录下 samples/httpbin/httpbin.yaml

##################################################################################################
# httpbin service
##################################################################################################
apiVersion: v1
kind: ServiceAccount
metadata:
  name: httpbin
---
apiVersion: v1
kind: Service
metadata:
  name: httpbin
  labels:
    app: httpbin
spec:
  ports:
  - name: http
    port: 8000
    targetPort: 80
  selector:
    app: httpbin
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: httpbin
spec:
  replicas: 1
  selector:
    matchLabels:
      app: httpbin
      version: v1
  template:
    metadata:
      labels:
        app: httpbin
        version: v1
    spec:
      serviceAccountName: httpbin
      containers:
      - image: docker.io/kennethreitz/httpbin
        imagePullPolicy: IfNotPresent
        name: httpbin
        ports:
        - containerPort: 80

kubectl apply -f samples/httpbin/httpbin.yaml

查看所有的pod
kubectl get pod

2. 定义Ingress gateway

gateway2.yaml清单如下
可以看到，依然使用的是gateway来部署Ingress，选择Istio默认的Ingressgateway作为selector，同时暴露80端口作为他的访问点。这里设置了一个host，希望请求是以这个方式进行访问

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: httpbin-gateway
spec:
  selector:
    istio: ingressgateway
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "httpbin.example.com"

kubectl apply -f linshi/gateway2.yaml

3. 定义对应的虚拟服务

还需要给gateway创建一个对应的虚拟服务，让他来对这个服务做一个简单的路由
虚拟服务的配置清单如下，vs.yaml
首先需要和gateway对应起来，

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: httpbin
spec:
  hosts:
  - "httpbin.example.com"
  gateways:
  - httpbin-gateway                          # 和gateway对应起来（绑定）
  http:
  - match:
    - uri:
        prefix: /status
    - uri:
        prefix: /delay
    route:
    - destination:
        port:
          number: 8000
        host: httpbin

kubectl apply -f linshi/vs.yaml

查看目前虚拟服务信息
kubectl get vs

4. 测试

curl -I -HHost:httpbin.example.com http://localhost/status/200