Jenkins

Build, test, and deploy applications using Jenkins, the leading open-source automation server.

When to Use This Skill

Use this skill when:

• Setting up Jenkins pipelines (declarative or scripted)
• Configuring Jenkins agents and executors
• Managing Jenkins plugins and security
• Creating shared libraries for pipeline reuse
• Integrating Jenkins with external tools

Prerequisites

• Jenkins server (2.x or later)
• Admin access to Jenkins
• Java 11+ on Jenkins server
• Basic Groovy understanding for pipelines

Declarative Pipeline

Create Jenkinsfile in repository root:

pipeline {
    agent any
    
    environment {
        DOCKER_REGISTRY = 'registry.example.com'
        APP_NAME = 'myapp'
    }
    
    stages {
        stage('Build') {
            steps {
                sh 'npm ci'
                sh 'npm run build'
            }
        }
        
        stage('Test') {
            steps {
                sh 'npm test'
            }
            post {
                always {
                    junit 'test-results/*.xml'
                }
            }
        }
        
        stage('Deploy') {
            when {
                branch 'main'
            }
            steps {
                sh './deploy.sh'
            }
        }
    }
    
    post {
        failure {
            mail to: 'team@example.com',
                 subject: "Pipeline Failed: ${env.JOB_NAME}",
                 body: "Check console output at ${env.BUILD_URL}"
        }
    }
}

Agent Configuration

Docker Agent

pipeline {
    agent {
        docker {
            image 'node:20'
            args '-v /tmp:/tmp'
        }
    }
    stages {
        stage('Build') {
            steps {
                sh 'npm ci && npm run build'
            }
        }
    }
}

Kubernetes Agent

pipeline {
    agent {
        kubernetes {
            yaml '''
                apiVersion: v1
                kind: Pod
                spec:
                  containers:
                  - name: node
                    image: node:20
                    command:
                    - sleep
                    args:
                    - infinity
                  - name: docker
                    image: docker:24-dind
                    securityContext:
                      privileged: true
            '''
        }
    }
    stages {
        stage('Build') {
            steps {
                container('node') {
                    sh 'npm ci && npm run build'
                }
            }
        }
    }
}

Labeled Agents

pipeline {
    agent { label 'linux && docker' }
    stages {
        stage('Build') {
            steps {
                sh 'make build'
            }
        }
    }
}

Parameters

pipeline {
    agent any
    
    parameters {
        string(name: 'BRANCH', defaultValue: 'main', description: 'Branch to build')
        choice(name: 'ENVIRONMENT', choices: ['dev', 'staging', 'prod'], description: 'Target environment')
        booleanParam(name: 'RUN_TESTS', defaultValue: true, description: 'Run tests?')
    }
    
    stages {
        stage('Deploy') {
            when {
                expression { params.ENVIRONMENT == 'prod' }
            }
            steps {
                sh "deploy.sh ${params.ENVIRONMENT}"
            }
        }
    }
}

Credentials

Using Credentials

pipeline {
    agent any
    
    environment {
        AWS_CREDS = credentials('aws-credentials')
        DOCKER_CREDS = credentials('docker-hub')
    }
    
    stages {
        stage('Deploy') {
            steps {
                withCredentials([
                    usernamePassword(
                        credentialsId: 'github-token',
                        usernameVariable: 'GH_USER',
                        passwordVariable: 'GH_TOKEN'
                    )
                ]) {
                    sh 'git push https://${GH_USER}:${GH_TOKEN}@github.com/repo.git'
                }
            }
        }
    }
}

Parallel Stages

pipeline {
    agent any
    
    stages {
        stage('Tests') {
            parallel {
                stage('Unit Tests') {
                    steps {
                        sh 'npm run test:unit'
                    }
                }
                stage('Integration Tests') {
                    steps {
                        sh 'npm run test:integration'

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