What is a Multibranch Pipeline in Jenkins?

Key takeaways

• Multibranch pipelines in Jenkins is a powerful feature to automate build, test, and deploy processes for multiple branches in a Git repository.

• By using a Jenkinsfile in each branch, you can define the pipeline stages and steps, allowing Jenkins to automatically trigger and execute pipelines for each branch.

• Multibranch Pipelines reduce manual effort and ensure consistency in the software delivery process, leading to faster and more reliable deployments.

A Multibranch Pipeline project in Jenkins is used to build Jenkins pipeline jobs for each branch in the source code repository. It’s especially helpful for projects with numerous branches because it allows us to design and manage pipelines for each branch separately.

Here’s an easy guide for setting up a Jenkins Multibranch Pipeline, starting off with the prerequisites needed beforehand.

Prerequisites

• Jenkins is installed and configured.

• Jenkins pipeline plugin is installed on our systems.

Let's move on to how to set up a Multibranch Pipeline.

Steps

1. Create a Git repository

• Set up a simple Git repository with a Jenkinsfile at its root directory.

• The Jenkinsfile defines the pipeline stages.

2. Jenkins configuration

• Create a new Multibranch Pipeline job in Jenkins.

• Configure the job to use the Git repository as the source.

• Configure the branch sources (e.g., to build all branches).

3. Save and run

• Save the Multibranch Pipeline job configuration.

• Jenkins will scan the repository and create pipeline jobs for each branch that matches the criteria.

• Each branch with a Jenkinsfile will trigger its respective pipeline job.

The Jenkinsfile example

Here’s a basic Jenkinsfile example that includes a simple build stage for demonstration purposes:

The provided Jenkins pipeline code defines a simple pipeline with a single stage named Build. This stage, executed on any available agent, consists of a single step that prints a message to the console. While this is a basic example, Jenkins pipelines offer immense flexibility. Adding more stages and steps allows you to create complex pipelines that automate various tasks, such as building, testing, and deploying applications. You can customize these pipelines to fit your specific project needs, define parallel stages for concurrent execution, implement conditional logic, and incorporate error-handling mechanisms to ensure robust and efficient software delivery.

Note: Please note that this example assumes that the reader has a basic understanding of setting up Jenkins, creating pipeline jobs, and defining Jenkinsfile pipelines. Adjust the pipeline stages and configurations in the Jenkinsfile based on the project’s requirements for building, testing, and deployment.

Expected behavior

The expected behavior of the steps above is described below:

• Jenkins will create pipeline jobs for each branch that contains a Jenkinsfile.

• When a change is pushed to any branch, Jenkins will automatically detect the change, trigger a build for that branch’s pipeline, and execute the defined stages in the Jenkinsfile.

Benefits of Multibranch Pipelines

• There is no need for manual configuration for every branch. Jenkins handles this automatically.

• They ensures consistent CI/CD processes across all branches, minimizing errors and discrepancies.

• Changes in one branch do not affect the builds of others.

• Each branch can run its own set of tests, helping identify issues specific to that branch early in the development cycle.

Test yourself

Before moving on to the conclusion, let's test your understanding.

Conclusion

By effectively utilizing Jenkins Multibranch Pipelines, you can streamline your development workflow for projects with numerous branches. This approach enables automated and efficient management of pipelines for each branch, significantly reducing manual effort and ensuring consistency in your build, test, and deployment processes. By following the outlined steps and customizing the Jenkinsfile to suit your project's specific needs, you can harness the full potential of Jenkins Multibranch Pipelines to enhance your software delivery pipeline.