How to create a Pipeline in Jenkins using Jenkinsfile

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Jenkinsfile is a file, where you can write all the build commands and store the file in the GitHub repository, then Jenkins Pipeline can reference it to execute the commands

Create a Jenkinsfile named 01-Jenkinsfile-helloworld inside cicd

mkdir cicd
ls -l
cd cicd
vi 01-Jenkinsfile-helloworld
ls -l

pipeline {
  agent any
  stages {
    stage ('Build') {
      steps {
        sh 'echo Hello Build stage'
      }
    }
    stage ('Test') {
      steps {
        sh 'echo hello Test stage'
      }
    }
  }
}

Reference: Pipeline Syntax

vignesh ~/code/devopspilot1/hello-world-java [main] $ ll
total 16
-rw-r--r--  1 vignesh  staff   762 Jul 12 22:56 README.md
-rw-r--r--  1 vignesh  staff  1414 Jul 12 22:56 pom.xml
drwxr-xr-x  4 vignesh  staff   128 Jul 12 22:56 src

vignesh ~/code/devopspilot1/hello-world-java [main] $ mkdir cicd

vignesh ~/code/devopspilot1/hello-world-java [main] $ ls -l
total 24
-rw-r--r--  1 vignesh  staff   210 Jul 15 19:31 01-Jenkinsfile-helloworld
-rw-r--r--  1 vignesh  staff   762 Jul 12 22:56 README.md
drwxr-xr-x  2 vignesh  staff    64 Jul 15 19:32 cicd
-rw-r--r--  1 vignesh  staff  1414 Jul 12 22:56 pom.xml
drwxr-xr-x  4 vignesh  staff   128 Jul 12 22:56 src

vignesh ~/code/devopspilot1/hello-world-java [main] $ cd cicd

vignesh ~/code/devopspilot1/hello-world-java/cicd [main] $ vi 01-Jenkinsfile-helloworld

vignesh ~/code/devopspilot1/hello-world-java/cicd [main] $ ls -l
total 8
-rw-r--r--  1 vignesh  staff  210 Jul 15 19:34 01-Jenkinsfile-helloworld

Check Git status

cd ..
git status

vignesh ~/code/devopspilot1/hello-world-java/cicd [main] $ cd ..

vignesh ~/code/devopspilot1/hello-world-java [main] $ git status
On branch main
Your branch is up to date with 'origin/main'.

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	cicd/

nothing added to commit but untracked files present (use "git add" to track)

Add the file and push it to the GitHub repository

git add .
git status
git commit -m "Added Jenkinsfile 01-Jenkinsfile-helloworld"
git push origin main

vignesh ~/code/devopspilot1/hello-world-java [main] $ git add .

vignesh ~/code/devopspilot1/hello-world-java [main] $ git status
On branch main
Your branch is up to date with 'origin/main'.

Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	new file:   cicd/01-Jenkinsfile-helloworld

vignesh ~/code/devopspilot1/hello-world-java [main] $ git commit -m "Added Jenkinsfile 01-Jenkinsfile-helloworld" 
[main c548f08] Added Jenkinsfile 01-Jenkinsfile-helloworld
 1 file changed, 15 insertions(+)
 create mode 100644 cicd/01-Jenkinsfile-helloworld

vignesh ~/code/devopspilot1/hello-world-java [main] $ git push origin main
Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Delta compression using up to 10 threads
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 455 bytes | 455.00 KiB/s, done.
Total 4 (delta 1), reused 0 (delta 0), pack-reused 0
remote: Resolving deltas: 100% (1/1), completed with 1 local object.
To https://github.com/devopspilot1/hello-world-java.git
   27d7fcb..c548f08  main -> main

Verify cicd/01-Jenkinsfile-helloworld file is pushed to the GitHub repository

Goto Jenkins dashboard, click on New Item

Enter the Pipeline name 01-hello-world-java, select Pipeline, and then click OK

Select the Pipeline section, under Definition choose Pipeline script from SCM

From SCM choose Git and enter your GitHub repository URL

Under Branch Specifier change the branch name to main

Under Script Path enter the Jenkfinsfile path cicd/01-Jenkinsfile-helloworld and click on Save

Click on Build Now

Goto Console Output, first it obtained the Jenkinsfile cicd/01-Jenkinsfile-helloworld from the GitHub repository, then clones the GitHub Repository and executed the commands defined in the stages

In Jenkinsfile you had 2 stages Build and Test, in both the stages it executes the sh step to execute the echo commands