How to Set Up Jenkins for Automation: A Complete Beginner’s Guide to CI/CD

📘 Chapter 3: Creating Your First Jenkins Job

🔐 Introduction

With Jenkins installed and configured, it’s time to take your first hands-on step into automation — by creating your very first Jenkins job. A Jenkins job is essentially a task or project that Jenkins will execute for you automatically. Whether it's building code, running tests, or deploying an application, a job is the core unit of execution in Jenkins.

This chapter walks you through the complete process of creating a Jenkins job, step-by-step. You’ll learn how to create freestyle jobs, connect to version control, add build steps, trigger actions, and view output — all with real-world examples and screenshots in mind.

🧠 What is a Jenkins Job?

A Jenkins job (or project) is a runnable task that can be configured to:

• Pull code from a version control system
• Compile and build applications
• Run scripts, test suites, or deployments
• Notify teams on success or failure
• Execute at scheduled times or based on triggers

🧱 Types of Jenkins Jobs

In this chapter, we focus on the Freestyle Project, which is ideal for beginners.

🛠️ Step-by-Step: Create Your First Jenkins Job

✅ Step 1: Log In to Jenkins

1. Visit your Jenkins instance (e.g., http://localhost:8080)
2. Use your admin credentials to log in
3. You’ll land on the Jenkins Dashboard

✅ Step 2: Create a New Freestyle Job

1. Click on “New Item” in the left-hand menu
2. Enter a name: HelloWorld-Build
3. Select “Freestyle project”
4. Click OK

You’ll be redirected to the job configuration screen.

✅ Step 3: Configure Source Code Management (Git)

If you want to automate a project from GitHub:

1. Scroll to Source Code Management
2. Select Git
3. Enter your Git repository URL
4. Add credentials (if private repo)
5. Optionally specify a branch (e.g., main)

✅ Step 4: Add a Build Step

1. Scroll to Build section
2. Click “Add build step” → Execute shell (Linux/Mac) or Execute Windows batch command
3. Example command:

bash

echo "Hello Jenkins!"

You can also run:

bash

python3 myscript.py

npm install && npm run build

mvn clean package

✅ Step 5: Set Triggers (Optional)

To automate job execution:

Example for Poll SCM (every 15 mins):

bash

H/15 * * * *

✅ Step 6: Post-build Actions (Optional)

• Archive artifacts (e.g., build outputs, logs)
• Send email notifications
• Deploy to test/staging environments
• Trigger downstream jobs

✅ Step 7: Save and Run the Job

1. Click Save
2. You’ll return to the project dashboard
3. Click “Build Now”
4. Observe the build history and output

✅ Step 8: View Console Output

1. Under Build History, click on the build number (#1)
2. Click “Console Output”
3. You’ll see:

pgsql

Started by user admin

Running as SYSTEM

Building in workspace /var/jenkins_home/workspace/HelloWorld-Build

Hello Jenkins!

Finished: SUCCESS

Congratulations, you've created and run your first Jenkins job!

🧩 Understanding Jenkins Job Components

🧪 Sample Use Cases for Freestyle Jobs

🔄 What Happens Behind the Scenes

When you run a job, Jenkins:

1. Creates a workspace directory
2. Pulls source code (if configured)
3. Executes build/test commands
4. Collects and stores logs
5. Cleans up (if configured)

You can see all of this in the console output or the Workspace directory.

📘 Summary

Creating your first Jenkins job is like building your first robot — simple at first, but packed with potential. With Freestyle projects, you can quickly prototype automation tasks, build test scripts, or deploy apps. As you grow, you can evolve these jobs into powerful pipelines.

Jenkins jobs are the stepping stones to full CI/CD pipelines — learn the basics, then scale the automation.