Multi-branch pipeline job creation in Jenkins - Step-by-Step Execution

Process Flow - Multi-branch pipeline job creation

Start Jenkins

↓

Create Multi-branch Pipeline Job

↓

Configure SCM Repository

↓

Scan Branches

↓

For each branch found

↓

Create Pipeline Job for Branch

↓

Run Pipeline Job

↓

Collect Results

↓

End

This flow shows how Jenkins creates a multi-branch pipeline job, scans branches in the repository, creates jobs for each branch, and runs them.

Execution Sample

Jenkins

pipeline {
  agent any
  stages {
    stage('Build') {
      steps { echo "Building branch ${env.BRANCH_NAME}" }
    }
  }
}

A simple Jenkins pipeline script that prints the branch name during the build stage.

Process Table

Step	Action	Details	Result
1	Start Jenkins	Jenkins server starts	Ready to create jobs
2	Create Multi-branch Pipeline Job	Job named 'MyMultiBranchJob' created	Job created with SCM config
3	Configure SCM Repository	Set Git URL to https://github.com/example/repo.git	SCM linked
4	Scan Branches	Jenkins scans repo branches	Branches found: main, dev, feature1
5	Create Pipeline Job for Branch 'main'	Job created for 'main'	Job ready to run
6	Create Pipeline Job for Branch 'dev'	Job created for 'dev'	Job ready to run
7	Create Pipeline Job for Branch 'feature1'	Job created for 'feature1'	Job ready to run
8	Run Pipeline Job for 'main'	Pipeline script runs	Output: Building branch main
9	Run Pipeline Job for 'dev'	Pipeline script runs	Output: Building branch dev
10	Run Pipeline Job for 'feature1'	Pipeline script runs	Output: Building branch feature1
11	Collect Results	Jobs completed	Build results collected
12	End	All branches processed	Multi-branch pipeline complete

💡 All branches scanned and pipeline jobs executed successfully

Status Tracker

Variable	Start	After Step 4	After Step 7	Final
Branches Found	[]	[main, dev, feature1]	[main, dev, feature1]	[main, dev, feature1]
Jobs Created	0	0	3	3
Build Output	""	""	""	"Building branch main\nBuilding branch dev\nBuilding branch feature1"

Key Moments - 3 Insights

Why does Jenkins create separate jobs for each branch?

Because the multi-branch pipeline scans the repository and creates a job per branch to run pipelines independently, as shown in steps 5-7.

What happens if a new branch is added after the initial scan?

Jenkins will detect it on the next scan and create a new job for that branch, similar to the initial scan process in step 4.

Why do pipeline jobs print the branch name during the build?

The pipeline uses the environment variable BRANCH_NAME to identify the current branch, demonstrated in the build output in steps 8-10.

Visual Quiz - 3 Questions

Look at the execution table, at which step does Jenkins find the branches in the repository?

A Step 8

B Step 2

C Step 4

D Step 10

💡 Hint

Check the 'Action' column for scanning branches in the execution table.

According to the variable tracker, how many jobs are created after step 7?

A 3

B 1

C 0

D 5

💡 Hint

Look at the 'Jobs Created' row under 'After Step 7' in the variable tracker.

If a new branch 'hotfix' is added after step 4, what will happen next?

A Jenkins ignores it

B Jenkins creates a new job for 'hotfix' on next scan

C Jenkins deletes all jobs

D Jenkins merges 'hotfix' with 'main'

💡 Hint

Refer to key moment about new branches being detected on scans.

Concept Snapshot

Multi-branch pipeline job creation in Jenkins:
- Create a multi-branch pipeline job
- Configure SCM repository URL
- Jenkins scans branches automatically
- Creates pipeline jobs per branch
- Runs pipelines independently per branch
- Uses BRANCH_NAME env variable in scripts

Full Transcript

This visual execution shows how Jenkins creates a multi-branch pipeline job. First, Jenkins starts and the user creates a multi-branch pipeline job. Then, the SCM repository URL is configured. Jenkins scans the repository branches and finds multiple branches like main, dev, and feature1. For each branch, Jenkins creates a separate pipeline job. Each job runs the pipeline script, which prints the branch name using the BRANCH_NAME environment variable. After all jobs run, Jenkins collects the results and completes the multi-branch pipeline process. Variables like branches found and jobs created update step-by-step. Key moments clarify why Jenkins creates jobs per branch and how new branches are handled. The quiz tests understanding of scanning steps, job creation count, and branch addition behavior.