Jenkins

When to Use

• Legacy/Enterprise: You have massive, complex, custom requirements that only Jenkins plugins can handle.
• Fineness of Control: You need absolute control over the build environment.
• On-Premise: You cannot use Cloud CI.

Quick Start (Declarative Pipeline)

// Jenkinsfile
pipeline {
    agent { docker { image 'node:20' } }
    stages {
        stage('Build') {
            steps {
                sh 'npm ci'
                sh 'npm run build'
            }
        }
    }
}

Core Concepts

Master / Agent

Plugins

CasC (Configuration as Code)

Best Practices (2025)

• Use Declarative Pipelines: Avoid Scripted Pipelines unless absolutely necessary.
• Use Ephemeral Agents: Spin up a Pod for each build, destroy it after. No "Snowflake" build servers.
• Use Shared Libraries: For reusable Groovy logic across pipelines.

• Don't configure jobs in UI: Always use

  Jenkinsfile

  .
• Don't overload the Master: Run zero builds on the built-in controller node.

References

• Jenkins Documentation