Introduction to Jenkins

Introduction to Jenkins

Jenkins is an open-source automation server descended from the Hudson project. Its large integration ecosystem and programmable pipelines make it useful for continuous integration, delivery orchestration, scheduled automation, and controlled releases across many technology stacks.

Core ideas

• Continuous integration compiles, checks, and packages frequent changes so defects surface near their source.
• A job is a configured automation unit; each execution is recorded as a build.
• A pipeline models delivery as named stages and steps, normally versioned in a Jenkinsfile.
• Modern Jenkins documentation calls the coordinating service the controller; older material may use the legacy term “master.”

How it works

The controller receives events, loads job configuration, places work in the build queue, and assigns it to a compatible agent executor. The agent checks out source and runs tools. Status, logs, artifacts, and metadata return to Jenkins for visualization and downstream decisions.

Configuration example

pipeline {
  agent any
  stages {
    stage('Build') {
      steps { sh './gradlew assemble' }
    }
    stage('Verify') {
      steps { sh './gradlew check' }
    }
  }
}

The sample is intentionally small. In a real installation, replace hostnames, labels, credentials, retention, and commands with reviewed values from your own platform standards.

Production guidance

• Keep builds reproducible outside Jenkins; the server should orchestrate commands rather than contain hidden build logic.
• Use a pipeline for multi-stage delivery and retain the Jenkinsfile beside the application.
• Treat Jenkins as production infrastructure with ownership, upgrades, backups, monitoring, and recovery plans.

The chapter quiz follows this lesson and tests both terminology and safe operating choices.