Jenkins is an open-source Continuous Integration server capable to set up a chain of actions that help to achieve the continuous integration process in an automated manner.
Jenkins is the widely used application around the world with 300k installations and growing day by day. Jenkins is free and is entirely written in Java.
It is a server-based application and requires a web server like Apache Tomcat. The reason Jenkins became so popular is that of its monitoring of repeated tasks that arise during development.
For example, if the team is developing a project, Jenkins will continuously test your project builds and show you the errors in the early stages of your development.
Switching to Jenkins, software companies can accelerate their software development process since Jenkins can automate build and test at a rapid rate. Jenkins supports the complete development lifecycle of software from building, testing, documenting the software, deploying and other stages of a software development lifecycle.
In continuous Integration after a code commit, the software is built and tested immediately. In a large project with many developers, commits are made multiple times in a day. With each commit, code is built and tested. If the test is passed build is tested for deployment. If the deployment is a success, the code is pushed to production. This commit, build, test, and deploy is a continuous process and hence the name continuous integration/deployment.
A Continuous Integration Pipeline is a powerful model that consists of a set of tools designed to host, monitor, compile and test code, or code changes, like:
Nokia, a software company had implemented a concept called nightly build. After multiple commits from diverse developers during the day, the software is built every night. Since the software was built only once in a day, it’s a huge pain to isolate, identify, and fix the errors in a large codebase.
Later, they adopted Continuous Integration approach. The software was built and tested as soon as a developer committed code. If any error is detected, the respective developer can quickly fix the defect.
By default, Jenkins comes with a limited set of features. If you want to integrate your Jenkins installation with version control tools like Git, then you need to install plugins related to Git. In fact, for integration with tools like Maven, Amazon EC2, you need to install respective plugins in your Jenkins.