What is Jenkins?

Overview

Jenkins is an open-source automation server originally written in Java by Kohsuke Kawaguchi. It is the leading open-source CI/CD tool and provides hundreds of plugins to support building, testing, deploying, and automating any project.

Key Characteristics

• Platform independent — runs on any major OS.
• Community-supported and completely free to use.
• Purpose-built for CI/CD automation.
• If a team wants to implement continuous integration, Jenkins is usually the first choice.
• Supports a Master & Slave (Agent) architecture for distributed builds.
• Everything in Jenkins revolves around plugins — without plugins, you practically can't do anything useful.

A Bit of History

Jenkins was originally developed by Sun Microsystems in 2004 under the name Hudson. Hudson was an enterprise edition that required payment. After Oracle acquired Sun Microsystems, the project was renamed to Jenkins and became fully open-source.

Where Jenkins Fits in CI/CD

Whenever developers write code, Jenkins integrates all the code from every developer at a given point in time, then builds, tests, and delivers/deploys it to the client. This entire automated flow is what we call CI/CD.

• We can create pipelines of our own, tailored to the project.
• It gives us much faster, more frequent release cycles.
• Default Jenkins port number is 8080.