使用Jenkins和单个模板部署多个Kubernetes组件

前言

在持续集成和部署中，我们通常需要部署多个实例或组件到Kubernetes集群中。通过Jenkins的管道脚本，我们可以自动化这个过程。在本文中，我将演示如何使用Jenkins Pipeline及单个YAML模板文件（.tpl）来部署多个类似的Kubernetes组件，而不需要为每个组件提供单独的模板文件。

问题背景

参照：Jenkins Pipeline 脚本优化实践：从繁琐到简洁 批量生成 Kubernetes 部署模板：从 1 到20顺序模板

pipeline {
    agent none // Use none at the top level, each stage will define its own agent.

    environment {
        REGISTRY = "xxxx/master-metaspace"
        KUBE_CONFIG = "--namespace=master-metaspace --context=master"
        KUBE_YAML_PATH = "/home/jenkins/workspace/yaml/master-metaspace"
        // Assume that 'data' is defined elsewhere or injected as a parameter.
        BASE_WORKSPACE = "xxxxxxx" // 定义一个基础工作空间路径
    }

    stages {
        stage("GetCode") {
            agent { label "build01" }
            steps {
                script {
                    checkout scm: [
                        $class: 'GitSCM',
                        branches: [[name: env.branchName]],
                        extensions: [[$class: 'CloneOption', depth: 1, noTags: false, shallow: true]],
                        userRemoteConfigs: [[credentialsId: 'xxxx', url: env.gitHttpURL]]
                    ]
                }
            }
        }
        
        stage("Docker Builds") {
            parallel {
                stage('Build dataloader-game-ucenter') {
                    agent { label "build01" }
                    when { environment name: 'dataloader', value: 'true' }
                    steps {
                        buildAndPushDockerImage("dataloader-game-ucenter", env.data, env.BASE_WORKSPACE)
                    }
                }
                stage('Build datawriter-game-ucenter') {
                    agent { label "build01" }
                    when { environment name: 'datawriter', value: 'true' }
                    steps {
                        buildAndPushDockerImage("datawriter-game-ucenter", env.data, env.BASE_WORKSPACE)
                    }
                }
                stage('Build game-ucenter') {
                    agent { label "build01" }
                    when { environment name: 'game-ucenter', value: 'true' }
                    steps {
                        buildAndPushDockerImage("game-ucenter", env.data, env.BASE_WORKSPACE)
                    }
                }
            }
        }
        
        stage('Development Deployment') {
            parallel {
                stage("Deploy datawriter-game-ucenter") {
                    when { environment name: 'datawriter-game-ucenter', value: 'true' }
                    agent { label  "huaweiyun-xx" }
                    steps {
                        deployToKubernetes("datawriter-game-ucenter")
                    }
                }
                stage("Deploy dataloader-game-ucenter") {
                    when { environment name: 'dataloader', value: 'true' }
                    agent { label  "huaweiyun-xx" }
                    steps {
                        deployToKubernetes("dataloader-game-ucenter")
                    }
                }
                stage("Deploy game-ucenter") {
                    when { environment name: 'game-ucenter', value: 'true' }
                    agent { label  "huaweiyun-xx" }
                    steps {
                        deployToKubernetes("game-ucenter-1")
                        deployToKubernetes("game-ucenter-2")
                        deployToKubernetes("game-ucenter-3")
                        deployToKubernetes("game-ucenter-4")
                        ............................
                    }
                }
            }
        }
    }
}

// Define methods outside pipeline to avoid repetition

def buildAndPushDockerImage(String imageName, String tag, String workspacePath) {
    sh "cd ${workspacePath} && echo 'Current directory: \$(pwd)'" // 使用基础工作空间变量
    sh "cd ${workspacePath}/${imageName}&& docker build --build-arg NODE_ENV=$imageName -t $REGISTRY/$imageName:$tag ."
    withCredentials([usernamePassword(credentialsId: 'xxxxx', passwordVariable: 'dockerPassword', usernameVariable: 'dockerUser')]) {
        sh "docker login -u $dockerUser -p $dockerPassword $REGISTRY"
        sh "docker push $REGISTRY/$imageName:$tag"
    }
}

def deployToKubernetes(String kubernetesComponent) {
    String templateFile = "${KUBE_YAML_PATH}/${kubernetesComponent}.tpl"
    String outputFile = "${KUBE_YAML_PATH}/${kubernetesComponent}.yaml"
    sh "sed -e 's/{data}/$data/g' $templateFile > $outputFile"
    sh "sudo kubectl apply -f $outputFile $KUBE_CONFIG"
}

默认jenkins pipeline如上，我们有多个相似的游戏用户中心服务game-ucenter-*运行在Kubernetes集群中，它们都使用非常相似的Kubernetes YAML配置文件，配置文件之间的差异主要是一些标识符的不同（例如，服务的序号）。在传统的做法中，维护一系列几乎一样的模板文件（如game-ucenter-1.tpl, game-ucenter-2.tpl 等）将非常低效且易出错。

为了精简流程和提高效率，我们需要一个方法来通过单一模板生成多个配置文件，并由此部署多个不同的服务实例。

解决方案

使用Jenkins Pipeline中的sed命令和循环结构，我们可以从单一模板生成多个Kubernetes配置文件，并相应地部署每个服务实例。参照generate_templates.sh脚本

#!/bin/bash

# Define the name of the template file.
TEMPLATE_FILE="game-ucenter.tpl"

# Check if the template file exists.
if [ ! -f "$TEMPLATE_FILE" ]; then
    echo "Template file $TEMPLATE_FILE does not exist."
    exit 1
fi

# Loop to create files from game-ucenter-2 to pvp-game-20 based on the template.
for i in $(seq 1 20); do
    # Define the name of the new file.
    NEW_FILE="game-ucenter-${i}.yaml"
    
    # Copy the template to the new file.
    cp $TEMPLATE_FILE $NEW_FILE
    
    # Use 'sed' to replace 'game-ucenter-1' with 'game-ucenter-N' and save inline (-i option).
    sed -i "s/game-ucenter/game-ucenter-${i}/g" $NEW_FILE


    echo "Created file: $NEW_FILE"
done

echo "All files created successfully."

步骤 1: 定义Jenkins Pipeline

在我们的Jenkins脚本中，我们首先定义了基础环境变量和两个函数：buildAndPushDockerImage 和 deployToKubernetes。这些函数将用于构建Docker镜像并部署到Kubernetes

def buildAndPushDockerImage(String imageName, String tag, String workspacePath) {
    sh "cd ${workspacePath} && echo 'Current directory: \$(pwd)'" // 使用基础工作空间变量
    sh "cd ${workspacePath}/${imageName}&& docker build --build-arg NODE_ENV=$imageName -t $REGISTRY/$imageName:$tag ."
    withCredentials([usernamePassword(credentialsId: 'xxx', passwordVariable: 'dockerPassword', usernameVariable: 'dockerUser')]) {
        sh "docker login -u $dockerUser -p $dockerPassword $REGISTRY"
        sh "docker push $REGISTRY/$imageName:$tag"
    }
}

def deployToKubernetes(String kubernetesComponent) {
    String templateFile = "${KUBE_YAML_PATH}/${kubernetesComponent}.tpl"
    String outputFile = "${KUBE_YAML_PATH}/${kubernetesComponent}.yaml"
    sh "sed -e 's/{data}/$data/g' $templateFile > $outputFile"
    sh "sudo kubectl apply -f $outputFile $KUBE_CONFIG"
}

步骤 2: 修改deployToKubernetes函数

接下来，我们需要修改deployToKubernetes函数，以便它能够接受组件名称，并使用单一模板文件创建具体的配置文件。

def deployToKubernetes(String kubernetesComponent, int instance=1, int totalInstances=1) {
    // 检查实例值
    if (instance < 1) {
        error("实例数必须大于0")
    }

    // 根据 instance 的值来定义资源的名称和文件名
    String nameSuffix = totalInstances > 1 ? "-${instance}" : "" // 总是添加后缀，除非只有一个实例
    String outputFileName = "${kubernetesComponent}${nameSuffix}.yaml"
    String templateFile = "${KUBE_YAML_PATH}/${kubernetesComponent}.tpl"
    String outputFile = "${KUBE_YAML_PATH}/${outputFileName}"
    String nameReplacement = "${kubernetesComponent}${nameSuffix}"

    sh """
        cat "${templateFile}" \
        | sed 's/{data}/${data}/g' \
        | sed 's/name: ${kubernetesComponent}/name: ${nameReplacement}/g' \
        | sed 's/app: ${kubernetesComponent}/app: ${nameReplacement}/g' \
        > "${outputFile}"
    """

    // 使用 KUBE_CONFIG 应用 Kubernetes 配置
    sh "kubectl apply -f ${outputFile} ${KUBE_CONFIG}"
}

对于单实例的业务，例如Deploy dataloader-game-ucenter，我们不需要传递实例编号。

stage("Deploy dataloader-game-ucenter") {
    when { environment name: 'dataloader', value: 'true' }
    agent { label  "huaweiyun-xx" }
    steps {
        deployToKubernetes("dataloader-game-ucenter")
    }
}

对于多实例。我这里生成 规则优点强迫症了。如果多实例我生成的规则要求符合game-ucenter-1,game-ucenter-2,game-ucenter-3…顺序，当单个实例的时候则保持原来的不加标签：

                stage("Deploy game-ucenter") {
                    when { environment name: 'game-ucenter', value: 'true' }
                    agent { label  "k8s-node-06" }
                    steps {
                        script {
                          int instances = 2 // 假设我们有2个实例
                          for (int i = 1; i <= instances; i++) {
                            def componentName = "game-ucenter"
                            deployToKubernetes("game-ucenter", i, instances)

                    }
                }
            }
        }

步骤 3: 准备模板文件

我们的模板文件game-ucenter.tpl将包含通用的Kubernetes服务或部署定义，使用占位符game-ucenter-1 game-ucenter-2来标识应该被替换的地方。

# game-ucenter-1.tpl (示例部分)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: game-ucenter
spec:
  replicas: 1
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: game-ucenter
  template:
    metadata:
      labels:
        app: game-ucenter
    spec:
      containers:
        - name: game-ucenter
          image: xxxx/xxx/game-ucenter:{data}
          envFrom:
          - configMapRef:
              name: deploy
          ports:
            - containerPort: 80
          resources:
            requests:
              memory: "4096M"
              cpu: "2000m"
            limits:
              memory: "4096M"
              cpu: "2000m" 
          livenessProbe:
            httpGet:
              scheme: HTTP
              path: /test.html
              port: 80
            initialDelaySeconds: 20
            periodSeconds: 120
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            httpGet:
              scheme: HTTP
              path: /test.html
              port: 80
            initialDelaySeconds: 20
            periodSeconds: 120
      imagePullSecrets:                                              
        - name: xxx
---

apiVersion: v1
kind: Service
metadata:
  name: game-ucenter
  labels:
    app: game-ucenter
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: game-ucenter

# ...

步骤 4: 执行Jenkins Pipeline

当Jenkins Pipeline运行到"Development Deployment"阶段时，它将循环创建和应用game-ucenter-1.yaml到game-ucenter-2.yaml的配置文件，从而部署2个game-ucenterdeployment服务实例。

并保证单个实例的原有命名规则：

通过这一方法，我们不再需要为每个服务实例维护一个单独的模板文件，而是可以通过一个模板文件和Jenkins Pipeline的自动化来简化服务部署工作。这样做不仅提升了效率，也降低了出错的风险。

注意：

以上代码和命令为示例性质，可能需要根据您具体的Jenkins环境和Kubernetes集群进行相应的调整。在生产环境中部署之前，请确保进行充分的测试。