上一章我們分享了k8s的網路代理模式，今天我們來分享一下k8s中的服務發現。

1.環境變數模式的服務發現

k8s預設為我們提供了通過環境變數來實現服務發現的功能，前提是

　　1.需要service在pod之前建立

　　2.適用於同一名稱空間

1.1建立service

[[email protected] ~]# cat netcore-service.yaml 
apiVersion: v1
kind: Service
metadata:
  name: netcore-service
  labels:
    app: netcore
spec:
  ports:
  
 
- name: http
    protocol: TCP
    port: 1001
    targetPort: 1000
    nodePort: 31111
  selector:
    app: cys-netcore
  type: NodePort

kubectl create -f netcore-service.yaml

1.2建立pod

[[email protected] ~]# cat netcore.yaml 
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: cys
 
-netcore
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cys-netcore
  template:
    metadata:
      labels:
        app: cys-netcore
    spec:
      containers:
      - name: cys-netcore
        image: chenyishi/webdocker_s_provider
        ports:
        - containerPort: 1000
 

        env:
        - name: serverpo

kubectl create -f netcore.yaml

1.3驗證

檢視環境變數

我們再以相同的方式再建立一組pod+service

[[email protected] ~]# cat netcore2.yaml 
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: cys-netcore2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cys-netcore2
  template:
    metadata:
      labels:
        app: cys-netcore2
    spec:
      containers:
      - name: cys-netcore2
        image: chenyishi/webdocker_s_provider
        ports:
        - containerPort: 1000
        env:
        - name: serverport
          value: "1000"

[[email protected] ~]# cat netcore-service2.yaml 
apiVersion: v1
kind: Service
metadata:
  name: netcore-service2
  labels:
    app: netcore2
spec:
  ports:
  - name: http
    protocol: TCP
    port: 1002
    targetPort: 1000
    nodePort: 31112
  selector:
    app: cys-netcore2
  type: NodePort

kubectl create -f netcore-service2.yaml
kubectl create -f netcore2.yaml

檢視env

我們進入容器，呼叫一下第一個service

至此，我們證明了可以通過env使service互通