Jenkins is a DevOps tool that is used to automate the processes involved in deploying web apps.
Introduction to Jenkins
Jenkins is an open-source automation server that enables developers to build, test, and deploy their software. It is one of the most popular tools used in DevOps to implement continuous integration and continuous delivery (CI/CD) pipelines. In this article, we delve into Jenkins, exploring its key aspects, technologies, benefits, and real-world usage.
Jenkins Quick Facts
- Launched in 2011: Jenkins was created as a fork of the Oracle Hudson project and quickly gained popularity in the DevOps community.
- 300,000+ Active Installations: As of 2023, Jenkins has more than 300,000 active installations worldwide, demonstrating its widespread use in the industry.
- 1,500+ Plugins: Jenkins has a highly extensible ecosystem, with over 1,500 plugins available that extend its capabilities, making it suitable for many different programming languages and toolchains.
- 70+ Languages Localized: Jenkins has been localized into more than 70 languages, reflecting its global user base.
- 4,000+ Contributors: The Jenkins community is vast, with over 4,000 contributors as of 2023. These contributors add new features, fix bugs, write documentation, and more.
What is Jenkins?
Originally a fork of the Oracle Hudson project, Jenkins was created in 2011 and quickly became the go-to choice for teams wanting to implement CI/CD. As of 2023, Jenkins has over 300,000 active installations worldwide, making it one of the most widely adopted automation servers.
How does Jenkins work?
Jenkins automates various stages of the software delivery process. It continuously integrates changes from different developers, automatically builds and tests the software, and deploys it to production if the tests pass. It’s also highly customizable, with over 1,500 plugins to extend its functionality.
Jenkins Technologies and Concepts
A few key technologies and concepts form the backbone of Jenkins’ operation. Understanding these is crucial to effectively utilizing Jenkins in your DevOps workflow.
In Jenkins, a pipeline is a suite of plugins that supports implementing and integrating continuous delivery pipelines. The pipeline plugin provides a domain-specific language (DSL) to design your build, test, and deployment steps in code form.
The Jenkinsfile is a text file that contains the definition of a Jenkins pipeline. It is checked into source control, allowing the entire flow of the pipeline to be scriptable and versioned.
Jenkins has a robust plugin ecosystem, with over 1,500 available. These plugins enhance Jenkins’ capabilities, allowing it to work with many different languages, version control systems, and deployment technologies.
Jenkins uses agents to offload project builds from the master node, allowing for parallel execution and distributed builds. These agents can be on the same machine as the master or on different machines, providing flexibility and scalability.
Jenkins Use in DevOps
Jenkins excels as a DevOps tool due to its ability to automate software development stages, its integration capabilities, its support for Infrastructure as Code (IaC), and the transparency it offers in software delivery processes.
At its core, Jenkins is an automation server. It can automate every step of the software delivery process, from code integration and testing to deployment.
With its wide array of plugins, Jenkins can integrate with almost every tool in a DevOps pipeline, from source control management tools like Git to configuration management tools like Ansible.
Infrastructure as Code (IaC)
Jenkins pipelines are defined in code form via the Jenkinsfile, supporting IaC principles. This approach enhances version control, code review, and the consistency of pipeline procedures.
By providing a visual interface of the entire pipeline, Jenkins improves visibility into the software delivery process, making it easier to spot and address bottlenecks or failures.
Getting Started with Jenkins
Getting started with Jenkins involves understanding its core concepts, setting up a Jenkins server, and writing a simple Jenkinsfile to define your pipeline.
A Jenkins Tutorial
The video below will help you get started with Jenkins through a straight-forward example that takes a half hour to work through.
Begin by familiarizing yourself with key Jenkins concepts, like pipelines, Jenkinsfile, plugins, and agents. These concepts are fundamental to using Jenkins effectively.
Setting Up Jenkins
Jenkins can run on a variety of systems, from a personal computer to a high-capacity server. Installation involves downloading the Jenkins war file and running it in a Java runtime environment.
Writing Your First Jenkinsfile
Once Jenkins is set up, you can begin crafting your pipeline by writing a Jenkinsfile. Start with a simple pipeline that clones your code repository and runs some basic commands, then gradually add more complex steps like building, testing, and deploying your software.
Real-World Use Cases of Jenkins
Many companies across different industries use Jenkins to automate their software delivery pipelines. Here are some real-world examples:
Facebook uses Jenkins to handle many of their backend services, creating a robust continuous delivery environment.
Netflix, which deploys hundreds of times per day, uses Jenkins as part of their Spinnaker CD platform.
LinkedIn uses Jenkins for its highly complex build and test environments, handling millions of builds per week.
eBay, one of the world’s largest online marketplaces, leverages Jenkins to implement continuous delivery, accelerating their software delivery process.
These examples underscore Jenkins’ role as an invaluable asset for any organization aiming to automate and optimize their software delivery process. With its flexibility and extensibility, Jenkins is poised to remain a staple of DevOps practices for many years to come.