jenkins-实现kubernetes滚动发布实现原理

kubernetes滚动发布实现原理

1. kubernetes滚动发布实现原理

• 滚动发布

  每次只升级一个或多个服务，升级完成后加入生产环境，不断执行这个过程，直到集群中的全部旧版升级新版本。

• 优点

  • 用户无感知，平滑过渡

• 缺点

  • 部署周期长
  • 发布策略较复杂
  • 不易回滚

• 滚动发布结构图
  

  • 滚动发布

    1个 Deployment
    2个 ReplicaSet
    

2. 示例

• 修改deploy.yml文件

  ---
  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: web
    namespace: default
    annotations:       # 记录回滚参数
      kubernetes.io/change-cause: "$ROLL_BACK"   #记录到revision中的内容，记录版本号
  spec:
    replicas: 3 
    revisionHistoryLimit: 10 # 回滚标识RS历史版本保存数量
    selector:
      matchLabels:
        app: java-demo
    strategy:              #滚动更新
      rollingUpdate:
        maxSurge: 50%             # 滚动更新过程最大pod副本数
        maxUnavailable: 50%       # 滚动更新过程中最大不可用pod副本数，
      type: RollingUpdate
    template:
      metadata:
        labels:
          app: java-demo 
      spec:
        imagePullSecrets:
        - name: $SECRET_NAME 
        containers:
        - name: tomcat 
          image: $IMAGE_NAME 
          ports:
          - containerPort: 8080
            name: web
          livenessProbe:    #存活检查
            httpGet:
              path: /
              port: 8080
            initialDelaySeconds: 60
            timeoutSeconds: 5
            failureThreshold: 12
          readinessProbe:       # 健康检查
            httpGet:
              path: /
              port: 8080
            initialDelaySeconds: 60
            timeoutSeconds: 5
            failureThreshold: 12
  
  
  ---
  apiVersion: v1
  kind: Service
  metadata:
    name: web
  spec:
    type: NodePort
    selector:
      app: java-demo 
    ports:
      - protocol: TCP
        port: 80
        targetPort: 8080
  
  ---
  apiVersion: extensions/v1beta1
  kind: Ingress
  metadata:
    name: web 
  spec:
    rules:
    - host: java.scajy.org
      http:
        paths:
        - path: /
          backend:
            serviceName: web 
            servicePort: 80
  
  

• 修改jenkinsfile文件

  // 公共
  def registry = "harbor.scajy.org"           // harbor的连接地址
  // 项目
  def project = "k8s"                      // harbor的项目目录
  def app_name = "java-demo"                       // 项目名称
  def image_name = "${registry}/${project}/${app_name}:${BUILD_NUMBER}"      // 推送harbor的全路径，BUILD_NUMBER是取得当前jenkins构建的号，为版本号
  def roll_back = "${app_name}-${BUILD_NUMBER}"                              // 增加回滚标识
  def git_address = "git@10.100.24.87:k8s/tomcat_java_demo.git"             // 根据项目要更换git地址
  def base_image = "${registry}/library/tomcat:latest"                      // 构建项目需要的基础镜像
  // 认证
  def secret_name = "registry-pull-secret"
  def docker_registry_auth = "b6085682-39e7-458f-96c0-f139fe17f2e1"       // harbor仓库key，这个key要去jenkins查找
  def git_auth = "d8bf675c-5dd4-4bf4-a4f7-4e8c1be1c002"                   // git代码仓库的key，这个key要去jenkins查找
  def k8s_auth = "a16f5236-7cdc-4216-a4ec-c52346751f56"                   // k8s连接的key
  
  podTemplate(label: 'jenkins-slave', cloud: 'kubernetes', containers: [
      containerTemplate(
          name: 'jnlp',          // 模板
          image: "${registry}/library/jenkins-slave:1.8"       // jenkins-slave从服务器镜像
      ),
    ],
    volumes: [
      hostPathVolume(mountPath: '/var/run/docker.sock', hostPath: '/var/run/docker.sock'),
      hostPathVolume(mountPath: '/usr/bin/docker', hostPath: '/usr/bin/docker')
    ],
  ) 
  {
    node("jenkins-slave"){
        // 第一步
        stage('拉取代码'){
           checkout([$class: 'GitSCM', branches: [[name: '${Branch}']], userRemoteConfigs: [[credentialsId: "${git_auth}", url: "${git_address}"]]])
        }
        // 第二步
        stage('代码编译'){
            sh "mvn clean package -Dmaven.test.skip=true"
        }
        // 第三步
        stage('构建镜像'){
            withCredentials([usernamePassword(credentialsId: "${docker_registry_auth}", passwordVariable: 'password', usernameVariable: 'username')]) {
              sh """
                echo '
                  FROM  ${base_image}
                  RUN rm -rf /usr/local/tomcat/webapps/*
                  ADD target/*.war /usr/local/tomcat/webapps/ROOT.war 
                ' > Dockerfile
                ls 
                ls target
                docker build -t ${image_name} .
                docker login -u ${username} -p '${password}' ${registry}
                docker push ${image_name}
              """
              }
        }
        // 第四步
        stage('部署到K8S平台'){
            sh """
            sed -i 's#\$IMAGE_NAME#${image_name}#' deploy.yml                 # k8s 需要的镜像连接地址
            sed -i 's#\$SECRET_NAME#${secret_name}#' deploy.yml               # k8s 连接harbor证书的名称
  		  sed -i 's#\$ROLL_BACK#${roll_back}#' deploy.yml                   # k8s 回滚记录标识
            """
            kubernetesDeploy configs: 'deploy.yml', kubeconfigId: "${k8s_auth}"
        }
  
    }
  }
  
  

• 提交到gitlab
  
  

• gitlab验证是否修改
  

• jenkins构建发布部署

  • 发布前
    

  • 发布后
    
    

2.1 k8s集群查询验证

• 验证pod

  [root@k8s-master git]# kubectl get pods
  NAME                                      READY   STATUS        RESTARTS   AGE
  jenkins-0                                 1/1     Running       0          2d16h
  nfs-client-provisioner-5d99f8d7b9-562ff   1/1     Running       1          19d
  nginx-6799fc88d8-9fchc                    1/1     Running       0          18d
  web-69698d5d54-6hfsj                      1/1     Running       0          71s
  web-69698d5d54-mrt9x                      1/1     Running       0          71s
  web-69698d5d54-qphrp                      1/1     Running       0          71s
  web-77774786fc-9g55b                      1/1     Terminating   0          30m
  web-77774786fc-dbmqs                      0/1     Terminating   0          30m
  

• 验证回滚标识

  [root@k8s-master git]# kubectl rollout history deployment web
  deployment.apps/web 
  REVISION  CHANGE-CAUSE
  1         <none>
  2         <none>
  3         <none>
  4         <none>
  5         <none>
  6         <none>
  7         java-demo-15
  8         java-demo-16
  

• 浏览器访问测试
  

2.2 k8s-集群回滚上一个版本

• 回滚上一版本

  # 回滚到上一个版本
  [root@k8s-master git]# kubectl rollout  undo deployment web
  deployment.apps/web rolled back
  

• 查看pods是否在回滚

  [root@k8s-master git]# kubectl get pods
  NAME                                      READY   STATUS        RESTARTS   AGE
  jenkins-0                                 1/1     Running       0          2d16h
  nfs-client-provisioner-5d99f8d7b9-562ff   1/1     Running       1          19d
  nginx-6799fc88d8-9fchc                    1/1     Running       0          18d
  web-69698d5d54-6hfsj                      1/1     Running       0          4m48s
  web-69698d5d54-mrt9x                      1/1     Running       0          4m48s
  web-69698d5d54-qphrp                      0/1     Terminating   0          4m48s
  web-77774786fc-6mdp9                      0/1     Running       0          3s
  web-77774786fc-hdtn8                      0/1     Running       0          3s
  web-77774786fc-p2t7g                      0/1     Running       0          3s