架构图

image.png

MQTT

安装mqtt（也可以选择docker运行）

sudo apt-add-repository ppa:mosquitto-dev/mosquitto-ppa
sudo apt-get update
sudo apt-get install mosquitto
sudo apt-get install mosquitto-dev
sudo apt-get install mosquitto-clients
sudo service mosquitto status 

测试mqtt

#打开一个终端，执行以下命令订阅主题"mqtt"
mosquitto_sub -h localhost -t "mqtt" -v
#打开另外一个终端，发布消息到主题 “mqtt”
mosquitto_pub -h localhost -t "mqtt" -m "Hello MQTT"

创建应用

kubeedge examples

git clone https://github.com/kubeedge/examples.git
本章将使用 Web Demo 这个例子

创建CRD

 cd $GOPATH/src/github.com/kubeedge/examples/web-demo/kubeedge-web-app/deployments/
 kubectl create -f kubeedge-speaker-model.yaml
 kubectl create -f kubeedge-speaker-instance.yaml

deviceModel（描述某一类设备）

apiVersion: devices.kubeedge.io/v1alpha2
kind: DeviceModel
metadata:
 name: speaker-model
 namespace: default
spec:
 properties:
  - name: track           # 属性名称
    description: music track to play  # 描述
    type:
     string:     # 值类型
      accessMode: ReadWrite   #可读写
      defaultValue: ''      # 默认值

device(设备实例)

apiVersion: devices.kubeedge.io/v1alpha2
kind: Device
metadata:
  name: speaker-01
  labels:
    description: 'Speaker'
    manufacturer: 'test'
spec:
  deviceModelRef:
    name: speaker-model    # 关联的device model
  nodeSelector:     # 节点选择（这里是节点的标签）
    nodeSelectorTerms:
    - matchExpressions:
      - key: 'kubernetes.io/hostname'
        operator: In
        values:
        - aaa

创建云上的控制应用

 cd $GOPATH/src/github.com/kubeedge/examples/web-demo/kubeedge-web-app/deployments/
 kubectl create -f kubeedge-web-app.yaml

这里加上环境变量

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    k8s-app: kubeedge-web-app
  name: kubeedge-web-app
  namespace: default
spec:
  selector:
    matchLabels:
      k8s-app: kubeedge-web-app
  template:
    metadata:
      labels:
        k8s-app: kubeedge-web-app
    spec:
      nodeSelector:
        node-role.kubernetes.io/master: ""
      hostNetwork: true
      containers:
      - name: kubeedge-web-app
        image: xiangxinyong/kubeedge-web-app:v2.6
        imagePullPolicy: IfNotPresent
        env:
          - name: KUBERNETES_SERVICE_HOST
            value: "你的ip"       # 修改
          - name: KUBERNETES_SERVICE_PORT
            value: "6443"
        command: ["sleep"]
        args: ["10000000"]
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
  name: kubeedge-web-app
  namespace: default
rules:
- apiGroups: ["devices.kubeedge.io"]
  resources: ["devices"]
  verbs: ["get", "patch"]

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: kubeedge-web-app-rbac
  namespace: default
subjects:
  - kind: ServiceAccount
    name: default
roleRef:
  kind: Role
  name: kubeedge-web-app
  apiGroup: rbac.authorization.k8s.io

在网页访问需要加上svc

apiVersion: v1
kind: Service
metadata:
  name: kubeedge-webapp
  namespace: default
  labels:
    app: web
spec:
  ports:
  - nodePort: 30005
    port: 80
    protocol: TCP
    targetPort: 80
  selector:
    k8s-app: kubeedge-web-app 
  sessionAffinity: None
  type: NodePort

如果运行起来有问题，可以自己编译一下代码！

操作

1. 在页面选择歌曲8，play

   
   
   image.png

2. app会如下log

   
   
   image.png

3. kubectl describe device speaker-01，此时可以看到，value 已经变成了8

   
   
   image.png

4. 现在来看边缘的日志
   注意：需要打开边缘配置里的mqtt相关的配置
   这里会收到device的变更，并发布到mqtt

   
   
   image.png

5. 此时定义相关主题就可以获取到值的变更信息，mapper的主要逻辑就是做这个事情。
   先看效果

   
   
   image.png

import paho.mqtt.client as mqtt

def on_connect(client, userdata, flags, rc):
    print("Connected with result code: " + str(rc))

def on_message(client, userdata, msg):
    print(msg.topic + " " + str(msg.payload))

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect('127.0.0.1', 1883, 600) # 600为keepalive的时间间隔
client.subscribe('$hw/events/device/speaker-01/twin/update/document', qos=1)
client.loop_forever() # 保持连接