> For the complete documentation index, see [llms.txt](https://devops-3.gitbook.io/devops/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://devops-3.gitbook.io/devops/docs/module-11-jenkins/introduction-to-jenkins.md). # Introduction to Jenkins Jenkins is an open source automation tool written in Java programming language that allows continuous integration. Jenkins **builds** and **tests** our software projects which 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 us to continuously **deliver** our software by integrating with a large number of testing and deployment technologies. ### History of Jenkins Kohsuke Kawaguchi first developed Hudson in 2004 while working at Sun Microsystems. When Oracle acquired Sun Microsystems in 2010, there was a dispute between Oracle and the Hudson community with respect to the infrastructure used. There was a call for votes to change the project name from Hudson to Jenkins, which was overwhelmingly approved by the Hudson community on January 29, 2011, thereby creating the first “Jenkins” project. ### Architecture

Architecture

The main server of Jenkins is the Jenkins Master. It is a web dashboard which is nothing but powered from a war file. By default it runs on 8080 port. With the help of Dashboard, we can configure the jobs/projects but the build takes place in Nodes/Slave. Jenkins slave is used to execute the build jobs dispatched by the master. We can configure a project to always run on a particular slave machine, or particular type of slave machine, or simple let the Jenkins to pick the next available slave/node. ### Jenkins Workflow ![Jenkins Workflow](https://user-images.githubusercontent.com/69889600/214857610-4fc3e64c-a262-4a6b-9e4d-b5b4eed057c6.png) ### Continuous Integration Continuous Integration is a software development practice where code is continuously tested after a commit to ensure there are no bugs. The common practice is that whenever a code commit occurs, a build should be triggered. ### Continuous Deployment Continuous Deployment is a software development process where code changes to an application are released automatically into the production environment. ### Continuous Delivery Continuous delivery is a software development practice where a code change is built, tested, and then pushed to a non-production testing or staging environment but final deploy to production is made after approval. ### Advantages of Jenkins * Open source tool * Easy to install * Platform Independent * Support 1000+ plugins * Free of cost * Automates integration