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k8s_Microservices_Architecture

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Microservices Architecture

Example

首先创建Pod

  • 投票app 的pod

    voting-app-pod.yaml

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    apiVersion: v1
    kind: Pod
    metadata:
      name: voting-app-pod  #pod name
      labels:
        name: voting-app-pod
        app: demo-voting-app
    spec:
      containers:
        - name: voting-app #container name
          image: kodekloud/examplevotingapp_vote:v1 
          ports:
            - containerPort: 80 #the port on which the application listens for this voting app

    我们需要用containerPort属性为voting application明确指定port

  • result app的Pod

    result-app-pod.yaml

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    apiVersion: v1
    kind: Pod
    metadata:
      name: result-app-pod
      labels:
        name: result-app-pod
        app: demo-voting-app
    spec:
      containers:
        - name: result-app
          image: kodekloud/examplevotingapp_result:v1
          ports:
            - containerPort: 80

  • redis的Pod

    redis-pod.yaml

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    apiVersion: v1
    kind: Pod
    metadata: 
      name: redis-pod
      labels:
        name: redis-pod
        app: demo-voting-app
    spec:
      containers:
        - name: redis
          image: redis
          ports:
            - containerPort: 6379

  • postgres的Pod

    postgres-pod.yaml

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    apiVersion: v1
    kind: Pod
    metadata: 
      name: postgres-pod
      labels:
        name: postgres-pod
        app: demo-voting-app
    spec:
      contianers:
        - name: postgres
          image: postgres
          ports:
            - containerPort: 5432
          env:
            - name: POSTGRES_USER
              value: "postgres"
            - name: POSTGRES_PASSWORD
              value: "postgres"

  • worker的Pod

    worker-app-pod.yaml

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    apiVersion: v1
    kind: Pod
    metadata:
      name: worker-app-pod
      labels:
        name: worker-app-pod
        app: demo-voting-app
    spec:
      containers:
        - name: worker-app
          image: kodekloud/examplevotingapp_worker:v1
          ports:
            - containerPort: 80

创建service

  • redis的service (voting-app的Pod连接该service)

    redis-service.yaml

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    apiVersion: v1
    kind: Service
    metadata:
      name: redis #voting-app源码里面要连接的数据库为redis，因此这里命名为redis
      labels:
        name: redis-service
        app: demo-voting-app
    spec:
      ports:
        - port: 6379 #service暴露给其他连接的port
          targetPort: 6379 #service要连接的redis的Pod的port
      selector: #link the service to the Pod
        name: redis-pod #redis Pod的label
        app: demo-voting-app

  • postgres的service （result-app的Pod连接该service）

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    apiVersion: v1
    kind: Service
    metadata:
      name: db #result-app源码里面连接的数据库名称叫db，因此service要命名为db
      labels:
        name: postgre-service #随意定义
        app: demo-voting-app
    spec:
      ports:
        - port: 5432 
          targetPort: 5432 
      selector: #link the service to the Pod
        name: postgres-pod #要连接的postgre Pod的labels
        app: demo-voting-app

  • voting-app的service （用户从外面连接该service）

    voting-app-service.yaml

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    apiVersion: v1
    kind: Service
    metadata:
      name: result-service
      labels:
        name: voting-service
        app: demo-voting-app
    spec:
      type: NodePort #这里选择NodePort，因为要暴露给外面用户使用
      ports:
        - port: 80
          targetPort: 80
          nodePort: 30004
      selector: #voting-app的Pod的labels
        name: voting-app-pod
        app: demo-voting-app

  • result-app的service

    result-app-service.yaml

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    apiVersion: v1
    kind: Service
    metadata:
      name: result-service
      labels:
        name: result-service
        app: demo-voting-app
    spec:
      type: NodePort
      ports:
        - port: 80
          targetPort: 80
          nodePort: 30005
      selector: #result-app的Pod的labels
        name: result-app-pod
        app: demo-voting-app

启动Pod和Service

1
kubectl get pods,svc

使用Deployment来创建k8s微服务

1606112620439

用创建一个个Pod的方法并不能实现Pod的扩容（scale up），但选择Deployment能帮助我们实现，replicaSet，rolling update,rollback等功能

将上面例子中pod的定义文件改写成Deployment的定义文件。

  • voting-app的Deployment 文件

  • voting-app-deployment.yaml

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    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: voting-app-deploy
      labels:
        name: voting-app-deploy
        app: demo-voting-app
    spec:
      replicas: 1
      selector: #pod的labels
        matchLabels:
          name: voting-app-pod
          app: demo-voting-app
      template:
        metadata:
          name: voting-app-pod  #pod name
          labels:
            name: voting-app-pod
            app: demo-voting-app
        spec:
          containers:
            - name: voting-app #container name
              image: kodekloud/examplevotingapp_vote:v1 
              ports:
               - containerPort: 80

  • result-app-deployment.yaml

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    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: result-app-deploy
      labels:
        name: result-app-deploy
        app: demo-voting-app
    spec:
      replicas: 1
      selector: #pod的labels
        matchLabels:
          name: result-app-pod
          app: demo-voting-app
      template:
        metadata:
          name: result-app-pod
          labels:
            name: result-app-pod
            app: demo-voting-app
        spec:
          containers:
            - name: result-app
              image: kodekloud/examplevotingapp_result:v1
              ports:
                - containerPort: 80

  • redis的Deployment

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    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: redis-deploy
      labels:
        name: redis-deploy
        app: demo-voting-app
    spec:
      replicas: 1
      selector: #pod的labels
        matchLabels:
          name: redis-pod
          app: demo-voting-appp
      template:
        metadata: 
          name: redis-pod
          labels:
            name: redis-pod
            app: demo-voting-app
        spec:
          containers:
            - name: redis
              image: redis
              ports:
               - containerPort: 6379

  • postgres-deploy.yaml

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    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: postgres-deploy
      labels:
        name: postgres-deploy
        app: demo-voting-app
    spec:
      replicas: 1
      selector: #pod的labels
        matchLabels:
          name: postgres-pod
          app: demo-voting-app
      template:
        metadata: 
          name: postgres-pod
          labels:
            name: postgres-pod
            app: demo-voting-app
        spec:
          containers:
            - name: postgres
              image: postgres
              ports:
                - containerPort: 5432
              env:
               - name: POSTGRES_USER
                 value: "postgres"
               - name: POSTGRES_PASSWORD
                 value: "postgres"

  • worker-app-deploy.yaml

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    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: worker-app-deploy
      labels:
        name: worker-app-deploy
        app: demo-voting-app
    spec:
      replicas: 1
      selector: #pod的labels
        matchLabels:
          name: worker-app-pod
          app: demo-voting-app
      template:
        metadata:
          name: worker-app-pod
          labels:
            name: worker-app-pod
            app: demo-voting-app
        spec:
          containers:
            - name: worker-app
              image: kodekloud/examplevotingapp_worker:v1

依次创建deployment和Service

kubectl create -f voting-app-deployment.yaml

kubectl create -f voting-app-service.yaml