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KubeEdge 部署简单应用

KubeEdge 部署简单应用

参考（主要来源）

Kubeedge 安装,配置,HelloWorld

非常感谢该文作者

架构

KubeEdge Web Demo

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 Cloud
+-----------------------------+
|    +-------------------+    |
|    | KubeEdge Cloud    |    |     User Message
|    | +---------------+ |    |
|    | |   Server  :80 +<------------+
|    | +---------------+ |    |
|    +-------------------+    |
+-----------------------------+
             |
             |
             |   Sync Message
             |
 Edge        |
+------------v----------------------------+
|                                         |
|   +-----------------+    +------------+ |
|   |  KubeEdge Edge  |    | MQTT       | |
|   |                 +---->            | |
|   +-----------------+    +------------+ |
|                                         |
+-----------------------------------------+

部署的 KubeEdge 由两个节点组成，一个节点为主节点，一个节点为边缘节点，如果部署参照前面的文章，以下为两个节点的情况

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NAME     STATUS   ROLES        AGE    VERSION
edge1    Ready    agent,edge   28h    v1.17.1-kubeedge-v1.3.1
ubuntu   Ready    master       2d5h   v1.17.0

服务运行在主节点上，该服务会根据用户下达的请求向边缘节点的 MQTT 同步消息。此程序运行于 80 端口

前置要求

KubeEdge 以部署完毕，在主节点上一个有 KubeEdge 源码并正确地将其加入到 GOPATH 中

主节点部署

clone 代码 kubeedge/examples 至本地，进入到目录 github.com/kubeedge/examples/kubeedge-web-demo/ 下。之后的讲解都以此为根目录

修改 utils/kubeclient.go 内容为

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package utils

import (
  "errors"
  "fmt"
  "io/ioutil"
  "k8s.io/client-go/rest"
  certutil "k8s.io/client-go/util/cert"
  "net"
  "os"
)

var KubeQPS = float32(5.000000)
var KubeBurst = 10
var KubeContentType = "application/vnd.kubernetes.protobuf"
var ErrNotInCluster = errors.New("unable to load in-cluster configuration, KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT must be defined")

func InClusterConfig() (*rest.Config, error) {
  const (
    tokenFile  = "/var/run/secrets/kubernetes.io/serviceaccount/token"
    rootCAFile = "/var/run/secrets/kubernetes.io/serviceaccount/ca.crt"
  )
  host, port := os.Getenv("KUBERNETES_SERVICE_HOST"), os.Getenv("KUBERNETES_SERVICE_PORT")
  if len(host) == 0 || len(port) == 0 {
    return nil, ErrNotInCluster
  }

  token, err := ioutil.ReadFile(tokenFile)
  if err != nil {
    return nil, err
  }

  tlsClientConfig := rest.TLSClientConfig{}

  if _, err := certutil.NewPool(rootCAFile); err != nil {
    fmt.Errorf("Expected to load root CA config from %s, but got err: %v", rootCAFile, err)
  } else {
    tlsClientConfig.CAFile = rootCAFile
  }

  return &rest.Config{
    Host:            "https://" + net.JoinHostPort(host, port),
    TLSClientConfig: tlsClientConfig,
    BearerToken:     string(token),
  }, nil
}

// KubeConfig from flags
func KubeConfig() (conf *rest.Config, err error) {
  kubeConfig, err := InClusterConfig()
  if err != nil {
    return nil, err
  }
  kubeConfig.QPS = KubeQPS
  kubeConfig.Burst = KubeBurst
  kubeConfig.ContentType = KubeContentType
  return kubeConfig, err
}

修改 deployments/kubeedge-speaker-instance.yaml 为

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apiVersion: devices.kubeedge.io/v1alpha1
kind: Device
metadata:
  name: speaker-01
  labels:
    description: "Speaker"
    manufacturer: "test"
spec:
  deviceModelRef:
    name: speaker-model
  nodeSelector:
    nodeSelectorTerms:
      - matchExpressions:
          - key: ""
            operator: In
            values:
              - edge1

注意，最后的 edge1 为边缘节点的名称

修改文件 deployments/kubeedge-web-app.yaml 为

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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: kubeedge/kubeedge-web-app:v2.6
          imagePullPolicy: IfNotPresent
      restartPolicy: Always

修改 Dockerfile 为

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FROM centos:7.6.1810
LABEL maintainers="KubeEdge Authors"
LABEL description="KubeEdge Web App"

# Copy from build directory
COPY kubeedge-web-app /kubeedge-web-app
COPY static /static
COPY views /views

# Define default command
ENTRYPOINT ["/kubeedge-web-app"]

# Run the executable
CMD ["kubeedge-web-app"]

编译 Go 程序以及构造镜像

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go build -o kubeedge-web-app main.go
docker build . -t kubeedge/kubeedge-web-app:v2.6

添加用户权限

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sudo tee deployments/fabric8-rbac.yaml <<-'EOF'
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: fabric8-rbac
subjects:
  - kind: ServiceAccount
    # Reference to upper's `metadata.name`
    name: default
    # Reference to upper's `metadata.namespace`
    namespace: default
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io
EOF

部署资源文件

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kubectl create -f deployments/fabric8-rbac.yaml
kubectl create -f deployments/kubeedge-speaker-model.yaml
kubectl create -f deployments/kubeedge-speaker-instance.yaml
kubectl create -f deployments/kubeedge-web-app.yaml

查看主节点运行状态

执行

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kubectl get nodes

结果为

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NAME     STATUS   ROLES        AGE    VERSION
edge1    Ready    agent,edge   28h    v1.17.1-kubeedge-v1.3.1
ubuntu   Ready    master       2d5h   v1.17.0

执行

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kubectl get deployments

结果为

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NAME               READY   UP-TO-DATE   AVAILABLE   AGE
kubeedge-web-app   1/1     1            1           160m

执行

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kubectl get pods

结果为

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NAME                                READY   STATUS    RESTARTS   AGE
kubeedge-web-app-76d4755f59-qbjpd   1/1     Running   0          160m

执行

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kubectl describe pod kubeedge-web-app-76d4755f59-qbjpd | grep IP

结果为

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IP:           10.211.55.52
IPs:
  IP:           10.211.55.52

访问 http://10.211.55.52 即可看到页面

边缘端

此处不使用样例代码中运行在边缘端的代码，仅仅查看边缘端 MQTT 是否接受到来自于主节点的消息，代码如下：

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package main

import (
  "encoding/json"
  "fmt"
  "github.com/kubeedge/kubeedge/cloud/pkg/devicecontroller/types"
  "github.com/yosssi/gmq/mqtt"
  "github.com/yosssi/gmq/mqtt/client"
)

func main() {
  fmt.Println("Get music list successfully")

  cli := client.New(&client.Options{
    // Define the processing of the error handler.
    ErrorHandler: func(err error) {
      fmt.Println(err)
    },
  })

  fmt.Println("Create mqtt client successfully")

  stopchan := make(chan int)
  // Terminate the Client.
  defer cli.Terminate()

  // Connect to the MQTT Server.
  err := cli.Connect(&client.ConnectOptions{
    Network:  "tcp",
    Address:  "localhost:1883",
    ClientID: []byte("receive-client"),
  })
  if err != nil {
    panic(err)
  }
  fmt.Println("Connect mqtt client successfully")

  err = cli.Subscribe(&client.SubscribeOptions{
    SubReqs: []*client.SubReq{
      {
        TopicFilter: []byte(`$hw/events/device/speaker-01/twin/update/document`),
        QoS:         mqtt.QoS0,
        // Define the processing of the message handler.
        Handler: func(topicName, message []byte) {
          Update := &types.DeviceTwinDocument{}
          err := json.Unmarshal(message, Update)
          if err != nil {
            fmt.Println("Unmarshal error", err)
            fmt.Printf("Unmarshal error: %v\n", err)
          }
          fmt.Printf("%+v", Update)
        },
      },
    },
  })
  fmt.Println("Subscribe mqtt topic successfully")

  <-stopchan
  if err != nil {
    panic(err)
  } else {
    fmt.Println("Connection successfully")
  }
}

注意，需要将 kubeedge 官方代码正确添加到 GOPATH 下，正确配置到文件的 GOPATH，同时使用 go get 下载好相关的依赖。不要使用 go mod ，会出问题。编译好程序直接运行并保持运行状态。

检验

主节点运行命令查看 pod 日志

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kubectl logs -f kubeedge-web-app-76d4755f59-qbjpd

访问之前提到的页面，选择其中的一首歌点击播放，日志会有类似如下输出

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2020/06/16 11:00:04 PlayTrack: 7
2020/06/16 11:00:04 Track [ 7 ] will be played on speaker speaker-01

而运行在边缘端的程序也会有类似如下输出

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&{BaseMessage:{EventID:cd29c533-9c76-4c7f-b913-90310327526e Timestamp:1592305204859} Twin:map[track:0xc0000aa4c0]}

在边缘端安装 sqlite3 ，执行 sqlite3 /var/lib/kubeedge/edgecore.db 进入交互节点，执行

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select * from device_twin;

会有类似如下输出

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2|speaker-01|track||7||{"timestamp":1592305204859}||{"cloud":85047,"edge":0}||0|string|{}

至此，云边交互成功。