Jenkins & Its Use Cases

7 min readMar 12, 2021

Here we will be discussing what is Jenkins and discussing the Industrial Use Cases of the same.

So let us start…

Jenkins is a powerful application that allows continuous integration and continuous delivery of projects, regardless of the platform you are working on. It is a free source that can handle any kind of build or continuous integration. You can integrate Jenkins with a number of testing and deployment technologies.

Introduction to Jenkins

Continuous Integration is the most important part of DevOps that is used to integrate various DevOps stages. Jenkins is the most famous Continuous Integration tool, I know you are curious to know the reason behind the popularity of Jenkins, and if Jenkins is easy to learn.

Jenkins is an open-source automation tool written in Java with plugins built for Continuous Integration purposes. Jenkins is used to build and test your software projects continuously making it easier for developers to integrate changes to the project, and making it easier for users to obtain a fresh build. It also allows you to continuously deliver your software by integrating with a large number of testing and deployment technologies.

With Jenkins, organizations can accelerate the software development process through automation. Jenkins integrates development life-cycle processes of all kinds, including build, document, test, package, stage, deploy, static analysis, and much more.

Jenkins achieves Continuous Integration with the help of plugins. Plugins allow the integration of Various DevOps stages. If you want to integrate a particular tool, you need to install the plugins for that tool. For example Git, Maven 2 project, Amazon EC2, HTML publisher etc.

The image below depicts that Jenkins is integrating various DevOps stages:

In today’s DevOps world, continuous delivery and deployment are critical to delivering high-quality software product faster than ever before. Jenkins is an open-source continuous integration server written in Java. It is by far the most widely used tool for managing continuous integration builds and delivery pipelines. It helps developers in building and testing software continuously. It increases the scale of automation and is quickly gaining popularity in DevOps circles. One of the key advantages of Jenkins is that it requires little maintenance and has built-in GUI tool for easy updates. Jenkins also provides customized solution as there are over 400 plugins to support building and testing virtually any project. Basically, Jenkins integrates development life-cycle processes of all kinds, including build, document, test, package, stage, deploy, static analysis and much more.

With Jenkins you can configure alerts in several ways, for example, you can receive email notification, pop-ups, etc. and actually automate it. By implementing the right configuration for you, you get almost immediate feedback. You will always know if the build broke. You will get to know what the reason for job fail was and you can also get to know how you can revert it back.

Continuous Integration with Jenkins

Let us imagine a scenario where the complete source code of the application was built and then deployed on a test server for testing:

First, a developer commits the code to the source code repository.
Meanwhile, the Jenkins server checks the repository at regular intervals for changes.

Soon after a commit occurs, the Jenkins server detects the changes that have occurred in the source code repository.
Jenkins will pull those changes and will start preparing a new build.
If the build fails, then the pertinent team will be notified.
If the build is successful, then Jenkins deploys the build in the test server.
You could configure the pipeline (the script to run) to create the build with several steps:
Prepare, test (unit and integration tests), package, publish, deploy.
After running it, Jenkins generates a feedback, if these constraints are ok, the artifact is valid ( artifact is a source code compiled for testing, find more info here). And then Jenkins notifies the developers about the build and test results.
Jenkins will continue to check the source code repository for further changes made in the
source code, and the whole process will keep on repeating (functional tests).

Advantages of Jenkins

It is open source and it is user-friendly, easy to install and does not require additional installations or components.
It is free of cost.
Easily Configurable. Jenkins can be easily modified and extended. It deploys code instantly, generates test reports. Jenkins can be configured according to the requirements for continuous integrations and continuous delivery.
Platform Independent. Jenkins is available for all platforms and different operating systems, whether OS X, Windows or Linux.
Rich Plugin ecosystem. The extensive pool of plugins makes Jenkins flexible and allows building, deploying and automating across various platforms.
Easy support. Because it is open source and widely used, there is no shortage of support from large online communities of agile teams.
Developers write the tests to detect the errors of their code as soon as possible. So the developers don’t waste time on large-scale error-ridden integrations.
Issues are detected and resolved almost right away which keeps the software in a state where it can be released at any time safely.
Most of the integration work is automated. Hence fewer integration issues. This saves both time and money over the lifespan of a project.

Jenkins use cases

Let’s take a look at some of the main scenarios Jenkins plays a critical part in.

Continuous Integration (CI)

Continuous integration is a practice that forces developers to frequently integrate their code into a central repository. Instead of building out new features to the end without any quality measurement, every change is tested against the central repository in order to anticipate errors.

Every developer commits daily to a shared mainline and every commit triggers an automated process to build and test. If building or testing fails it can be detected and fixed within minutes without compromising the whole structure, workflow, and project. In that way, it is possible to isolate problems, solving them faster and provide higher-quality products.

Continuous Delivery (CD)

Continuous delivery is the ability to make changes of all types — such as new features, configuration changes, error fixes, experiments — into production in a safe and efficient manner using short work cycles.

The main goal in continuous delivery is to make deployments predictable as routine activities that can be achieved upon request. To be successful, the code needs to always be in a deployable state even when there is a scenario with lots of developers working and making changes on a daily basis. All of the code progress and changes are delivered in a nonstop way with high quality and low risks. The end result is one or more artifacts that can be deployed to production.

Continuous Deployment (CD)

Continuous deployment, also known as continuous implementation, is an advanced stage of continuous delivery that the automation process does not end at the delivery stage. In this methodology, every change that is validated at the automatic testing stage is later implemented at the production stage.

The fail fast strategy is always of the utmost importance when deploying to production. Since every change is deployed to production, it is possible to identify edge cases and unexpected behaviors that would be very hard to identify with automated tests. To fully take advantage of continuous deployment, it is important to have solid logging technology that allows you to identify the increasing error count on newer versions. In addition, a trustworthy orchestration technology like Kubernetes that will allow the new version to slowly be deployed to users until the full rollout or an incident is detected and the version is canceled.

Automation

As a job executor, Jenkins can be used to automate repetitive tasks like backup/restore databases, turn on or turn off machines, collect statistics about a service and other tasks. Since every job can be scheduled, repetitive tasks can have a desired time interval (like once a day, once a week, every fifth day of the month, and so forth).