How to implement CI/CD with Jenkins

Introduction

Jenkins is an open-source automation server that enables continuous integration and continuous delivery. Pipelines define the entire software lifecycle from commit to production.

Declarative Pipeline

Store your pipeline as code in a Jenkinsfile:

pipeline {
  agent any
  stages {
    stage('Build') {
      steps {
        sh 'npm install'
        sh 'npm run build'
      }
    }
    stage('Test') {
      steps {
        sh 'npm test'
      }
    }
    stage('Deploy') {
      steps {
        sh 'docker build -t myapp .'
        sh 'kubectl apply -f k8s/'
      }
    }
  }
}

Best Practices

• Run builds in ephemeral agents or containers for consistency.
• Store credentials in Jenkins Credential Manager, never in code.
• Parallelize independent stages to reduce pipeline duration.

For container image best practices, see how to build a Docker image and how to use Docker multi-stage builds for smaller images. For Kubernetes deployment, how to create a Kubernetes Helm chart from scratch simplifies releases.