Introduction to Jenkins: Architecture and Installation

An Introduction to Jenkins

Jenkins is an open-source platform that provides tools for managing and automating aspects of the software development lifecycle (SDLC). It was initially developed by Kohsuke Kawaguchi in 2001 with the mission of creating a universal automation server. Over the years, Jenkins has become widely adopted and is frequently utilized in DevOps teams worldwide due to its flexibility and ability to integrate with various programming languages and build tools.

Key Components of Jenkins Architecture

Jenkins consists of several components that contribute to its functionality:

Jenkins Controller (formerly known as Master)

The Jenkins Controller acts as the main organizer for the Jenkins system. It runs on every build and can manage multiple Jenkins Agents. The controller holds the central Jenkins configuration, manages agents and their connections, loads plugins, and coordinates project flow.

Jenkins Agent (formerly known as Slave)

Jenkins Agents are machines that connect to the Jenkins Controller to execute build jobs. They communicate with the controller over HTTP/HTTPS to retrieve jobs and execute them. These agents can be installed on different platforms such as Windows, Mac, or Linux systems. Multiple agents can be used to distribute the build load, improve performance, and create isolated environments.

Jenkins Node

A Jenkins Node refers to any machine that hosts a Jenkins build project. Both controllers and agents can function as nodes in the Jenkins system.

Jenkins Project (formerly known as Job)

Jenkins Projects are specific configurations that define the set of build actions performed by Jenkins. Each project represents a unique pipeline or development flow. Users can configure these projects according to their needs and preferences.

Jenkins Plugins

Jenkins has a vast ecosystem of plugins that extend its capabilities beyond the core functionalities. These plugins allow developers to customize the behavior of Jenkins according to their specific requirements.

Installing Jenkins

Installing Jenkins involves downloading the Jenkins WAR file and executing it with the appropriate parameters. The recommended approach is to use the generic Java WAR package, which requires Java 8 or higher to be installed on the system. After launching the war file, Jenkins will be accessible via a web interface and can be configured according to the user's needs.

Jenkins Pipeline

Jenkins Pipeline is a suite of plugins designed for implementing and integrating CI pipelines directly into Jenkins. It allows users to model and automate their entire SDLC process, from version control to deployment, using a declarative pipeline syntax. By defining the pipeline structure in a Jenkinsfile, developers can achieve better visibility and control over their development processes.

To summarize, Jenkins is an essential tool for automating many aspects of the software development process. With its flexible architecture and extensive ecosystem of plugins, it enables teams to streamline their processes and focus on delivering high-quality software efficiently.