In this section, we will walk through the process of creating a simple Jenkins pipeline. Pipelines are a powerful way to automate the build, test, and deployment processes in a continuous integration/continuous delivery (CI/CD) workflow. By the end of this section, you will have a basic understanding of how to create and run a Jenkins pipeline.

Before we dive into creating a pipeline, let's review some key concepts:

• Pipeline: A series of automated steps to build, test, and deploy code.
• Jenkinsfile: A text file that contains the definition of a Jenkins pipeline and is typically stored in the root directory of the source code repository.
• Stages: Logical divisions within a pipeline, such as "Build", "Test", and "Deploy".
• Steps: Individual tasks within a stage, such as running a shell command or executing a script.

1. Open Jenkins Dashboard: Navigate to your Jenkins dashboard.
2. Create New Item: Click on "New Item" on the left-hand side.
3. Enter Item Name: Provide a name for your pipeline job, e.g., "Simple-Pipeline".
4. Select Pipeline: Choose "Pipeline" from the list of options.
5. Click OK: Click the "OK" button to proceed.

1. Pipeline Configuration: Scroll down to the "Pipeline" section.

2. Definition: Select "Pipeline script" from the "Definition" dropdown.

3. Script: Enter the following script in the script text area:

   pipeline {
       agent any
   
       stages {
           stage('Build') {
               steps {
                   echo 'Building...'
               }
           }
           stage('Test') {
               steps {
                   echo 'Testing...'
               }
           }
           stage('Deploy') {
               steps {
                   echo 'Deploying...'
               }
           }
       }
   }
   

1. Save: Click the "Save" button at the bottom of the page.
2. Build Now: On the job's main page, click "Build Now" on the left-hand side to run the pipeline.

1. Build History: You will see a new build appear in the "Build History" section.
2. Console Output: Click on the build number and then "Console Output" to see the detailed log of the pipeline execution.

Let's break down the pipeline script:

• pipeline: The top-level block that defines the entire pipeline.
• agent any: Specifies that the pipeline can run on any available agent.
• stages: A block that contains multiple stages.
• stage('Build'): A stage named "Build".
  • steps: A block that contains the steps to be executed in this stage.
  • echo 'Building...': A step that prints "Building..." to the console.
• stage('Test'): A stage named "Test".
  • steps: A block that contains the steps to be executed in this stage.
  • echo 'Testing...': A step that prints "Testing..." to the console.
• stage('Deploy'): A stage named "Deploy".
  • steps: A block that contains the steps to be executed in this stage.
  • echo 'Deploying...': A step that prints "Deploying..." to the console.

1. Objective: Modify the existing pipeline to include a new stage called "Cleanup" that prints "Cleaning up..." to the console.
2. Steps:
   • Edit the pipeline script to add a new stage.
   • Save the changes.
   • Run the pipeline and verify the new stage is executed.

• Syntax Errors: Ensure that the pipeline script is correctly indented and all blocks are properly closed.
• Agent Specification: If you have specific requirements for the agent, replace agent any with the appropriate agent label.
• Stage Names: Use meaningful names for stages to make the pipeline easier to understand.

In this section, we covered the basics of creating a simple Jenkins pipeline. We learned how to define a pipeline using a Jenkinsfile, configure it in Jenkins, and run it. We also explored how to add new stages to the pipeline. This foundational knowledge will be essential as we move on to more advanced pipeline topics in the next sections.