1. 编写代码
2. 测试
3. 编写 Dockerfile
4. 构建打包 Docker 镜像
5. 推送 Docker 镜像到仓库
6. 编写 Kubernetes YAML 文件
7. 更改 YAML 文件中 Docker 镜像 TAG（ sed replace 镜像版本号）
8. 利用 kubectl 工具部署应用（一般滚动更新、或者金丝雀中断一次验证后继续发布）

def label = "slave-${UUID.randomUUID().toString()}"

def helmLint(String chartDir) {
    println "校验 chart 模板"
    sh "helm lint ${chartDir}"
}

def helmDeploy(Map args) {
    if (args.debug) {
        println "Debug 应用"
        sh "helm upgrade --dry-run --debug --install ${args.name} ${args.chartDir} -f ${args.valuePath} --set image.tag=${args.imageTag} --namespace ${args.namespace}"
    } else {
        println "部署应用"
        sh "helm upgrade --install ${args.name} ${args.chartDir} -f ${args.valuePath} --set image.tag=${args.imageTag} --namespace ${args.namespace}"
        echo "应用 ${args.name} 部署成功. 可以使用 helm status ${args.name} 查看应用状态"
    }
}

podTemplate(label: label, containers: [
  containerTemplate(name: 'golang', image: 'golang:1.14.2-alpine3.11', command: 'cat', ttyEnabled: true),
  containerTemplate(name: 'docker', image: 'docker:latest', command: 'cat', ttyEnabled: true),
  containerTemplate(name: 'helm', image: 'cnych/helm', command: 'cat', ttyEnabled: true),
  containerTemplate(name: 'kubectl', image: 'cnych/kubectl', command: 'cat', ttyEnabled: true)
], serviceAccount: 'jenkins', volumes: [
  hostPathVolume(mountPath: '/var/run/docker.sock', hostPath: '/var/run/docker.sock')
]) {
  node(label) {
    def myRepo = checkout scm
    // 获取 git commit id 作为镜像标签
    def imageTag = sh(script: "git rev-parse --short HEAD", returnStdout: true).trim()
    // 仓库地址
    def registryUrl = "harbor.k8s.local"
    def imageEndpoint = "course/devops-demo"
    // 镜像
    def image = "${registryUrl}/${imageEndpoint}:${imageTag}"

    stage('单元测试') {
      echo "测试阶段"
    }
    stage('代码编译打包') {
      try {
        container('golang') {
          echo "2.代码编译打包阶段"
          sh """
            export GOPROXY=https://goproxy.cn
            GOOS=linux GOARCH=amd64 go build -v -o demo-app
            """
        }
      } catch (exc) {
        println "构建失败 - ${currentBuild.fullDisplayName}"
        throw(exc)
      }
    }
    stage('构建 Docker 镜像') {
      withCredentials([[$class: 'UsernamePasswordMultiBinding',
        credentialsId: 'docker-auth',
        usernameVariable: 'DOCKER_USER',
        passwordVariable: 'DOCKER_PASSWORD']]) {
          container('docker') {
            echo "3. 构建 Docker 镜像阶段"
            sh """
              cat /etc/resolv.conf
              docker login ${registryUrl} -u ${DOCKER_USER} -p ${DOCKER_PASSWORD}
              docker build -t ${image} .
              docker push ${image}
              """
          }
      }
    }
    stage('运行 Helm') {
      withCredentials([file(credentialsId: 'kubeconfig', variable: 'KUBECONFIG')]) {
        container('helm') {
          sh "mkdir -p ~/.kube && cp ${KUBECONFIG} ~/.kube/config"
          echo "4.开始 Helm 部署"
          def userInput = input(
            id: 'userInput',
            message: '选择一个部署环境',
            parameters: [
                [
                    $class: 'ChoiceParameterDefinition',
                    choices: "Dev\\nQA\\nProd",
                    name: 'Env'
                ]
            ]
          )
          echo "部署应用到 ${userInput} 环境"
          // 选择不同环境下面的 values 文件
          if (userInput == "Dev") {
              // deploy dev stuff
          } else if (userInput == "QA"){
              // deploy qa stuff
          } else {
              // deploy prod stuff
          }
          helmDeploy(
              debug       : false,
              name        : "devops-demo",
              chartDir    : "./helm",
              namespace   : "kube-ops",
              valuePath   : "./helm/my-values.yaml",
              imageTag    : "${imageTag}"
          )
        }
      }
    }
    stage('运行 Kubectl') {
      withCredentials([file(credentialsId: 'kubeconfig', variable: 'KUBECONFIG')]) {
        container('kubectl') {
          sh "mkdir -p ~/.kube && cp ${KUBECONFIG} ~/.kube/config"
          echo "5.查看应用"
          sh "kubectl get all -n kube-ops -l app=devops-demo"
        }
      }
    }
    stage('快速回滚?') {
      withCredentials([file(credentialsId: 'kubeconfig', variable: 'KUBECONFIG')]) {
        container('helm') {
          sh "mkdir -p ~/.kube && cp ${KUBECONFIG} ~/.kube/config"
          def userInput = input(
            id: 'userInput',
            message: '是否需要快速回滚？',
            parameters: [
                [
                    $class: 'ChoiceParameterDefinition',
                    choices: "Y\\nN",
                    name: '回滚?'
                ]
            ]
          )
          if (userInput == "Y") {
            sh "helm rollback devops-demo --namespace kube-ops"
          }
        }
      }
    }
  }
}

使用 Jenkins Pipeline 流水线部署 Kubernetes 应用