Traditional software development processes were often slow and inflexible, making it difficult for companies to keep up with the pace of innovation and stay competitive. Agile software development was necessitated by the need to adapt quickly to changing market conditions and customer needs. It prioritizes flexibility, collaboration, and customer feedback, allowing companies to deliver high-quality software products more quickly and effectively.

By embracing agile development practices, organizations are now able to respond more quickly to changing requirements, reduce development costs, and improve overall product quality. One of the most commonly used agile development practices is CI/CD.

In this article, we’ll look at what CI/CD entails and the role played by Jenkins in creating CI/CD pipelines.

What is CI/CD?

A CI/CD pipeline is a set of practices that enable teams to rapidly and reliably deliver code changes to production. It is an essential component of modern software development that involves continuous integration (CI) and continuous delivery/deployment (CD) to streamline the software delivery process. With a CI/CD pipeline, developers can easily test and release code changes to end-users, ensuring that the software is always up-to-date and working as expected.

It is an efficient way to reduce errors and improve the overall quality of the software while also reducing the time and effort required to manage the software development lifecycle. It also allows a bigger team to work on the same application and track its bugs and upcoming releases.

There are several tools that you can use to implement CI/CD pipelines. One of the widely used tools is Jenkins.

To learn more about CI/CD pipelines, check out our blog post: What is CI/CD Pipeline in DevOps?

What is Jenkins?

Jenkins is an open-source automation tool that allows organizations to create and automate their CI/CD pipelines. Jenkins provides over a thousand plugins that serve various needs of the software development life cycle. The integration of different tools with Jenkins has been possible because of the huge community support for Jenkins.

These plugins are spread across different categories like source code management, development, build management, administration, etc. Some popular CI/CD plugins in Jenkins are Mailer, JUnit, Git, Pipeline, etc. The continuous integration facilitates the developers to merge the incremental changes. The continuous delivery/deployment facilitates the operations team to deploy the latest and most stable version to the production environment.

Jenkins enables organizations to speed up their software development life cycles by automating all components of the life cycle like build, test, deploy, etc.

Get started with Jenkins

You don’t have to install Jenkins to start building CI/CD pipelines. You can use our Jenkins Playground - a one-stop solution to explore, learn, and experiment with Jenkins. Here is a video demonstrating how the playground works.

Jenkins Architecture

Jenkins can be used as a standalone server or as a distributed server. The standalone server is suitable for experimenting with the tool. It is not possible to manage multiple builds with a standalone setup.

Below is a graphical representation of a distributed Jenkins setup:

The main components of the Jenkins distributed architecture are:

1. Master Node: The master node of Jenkins is responsible for orchestrating all the pipelines submitted to it. All the configuration of the pipelines can be done using the user interface of the Jenkins master. It communicates with the agent nodes to schedule the pipelines, monitor them, and show the output of the completed pipelines. It also stores all the credentials required for accessing servers, S3 storage, etc.
2. Agent Nodes: The agent nodes are responsible for the actual execution of the pipelines. All the steps mentioned in the pipelines are executed on these nodes. The agents need to be installed on the nodes so that the master node can connect with the agents. The agents can also be set up on different operating systems like Windows, Linux, and macOS, or be deployed dynamically using plugins like the Kubernetes plugin. Any number of nodes can be connected with the master node.

CI/CD pipeline Workflow

The flowchart above showcases a common CI/CD pipeline that teams implement for releasing their products. Such a pipeline can be automated using Jenkins.

First, the developers make the required changes to the code and push the updated code to a repository. The CI/CD pipeline needs to be triggered by a certain action or event. When using a GitHub repository, we use GitHub Actions to alert Jenkins to run a pipeline whenever a new commit changes the source code. You can also set it to be triggered at set time intervals.

These trigger points are the starting point of the pipelines. After the code is compiled, the code goes through a set of test cases written in the repository. To build and test the code, build steps need to be provided in the jobs using the Jenkins user interface.

The commands that need to be executed on the server are mentioned in these build steps. After the testing has been completed, the code can be packaged into a docker image. This image can then be pushed to the production server for deploying the new release. Similar to the compilation and testing stage, the build steps need to be written for deploying the new release on the production servers.

When creating a pipeline, you can create different jobs for each stage, like build, test, and deploy. These jobs can also be linked to each other by using post-build actions. For example, after the compilation of code is completed, the job of testing the executable will automatically get triggered. Then after successful testing, the working environment can be packaged and deployed on the server.

The flow of the pipelines may vary from team to team according to their projects and requirements. You can also create views using the Jenkins dashboard. These views help in showcasing those jobs that are relevant to the project.

Conclusion

CI/CD provides your team and the entire organization the speed and confidence it needs to deliver software to your customers reliably. Automating the steps in a CI/CD workflow facilitates the fast delivery of quality applications. Using a versatile automation tool like Jenkins will give you the power and freedom you need to create a reliable and secure pipeline that meets your needs.

More on Jenkins:

• CI/CD with Docker for Beginners
• DevOps vs. Agile - What is the Difference
• Top 10 Developer Tools in 2023