Jenkins

Jenkins
Name	Jenkins
Developer	Sun Microsystems (original), Kohsuke Kawaguchi (creator), CloudBees (major contributor)
Released	2006
Programming language	Java (programming language)
Operating system	Linux, Windows, macOS
License	MIT License (core components), various plugin licenses
Website	Jenkins.io

Jenkins

Jenkins is an open-source automation server for continuous integration and continuous delivery originally created by Kohsuke Kawaguchi. It orchestrates build, test, and deployment pipelines and integrates with numerous tools from version control to container runtimes. Jenkins has an extensive ecosystem of plugins and a large community spanning projects, corporations, and standards bodies.

Overview

Jenkins automates software delivery processes by coordinating tasks across tools such as Git, Subversion, Docker (software), Kubernetes, and Apache Maven. The project emerged in the mid-2000s amid rising adoption of practices promoted by advocates associated with Agile software development, Extreme Programming, and Continuous integration. Jenkins provides a web-based user interface, REST APIs, and scripting support to integrate with systems like JIRA, GitHub, Bitbucket, and GitLab. Major adopters include enterprises influenced by Netflix, Google, Facebook, and Microsoft case studies that shaped large-scale automation strategies.

History and development

The creator, Kohsuke Kawaguchi, developed the project while at Sun Microsystems to address repetitive build tasks tied to Hudson (software). The project split and evolved amid community governance discussions involving Oracle Corporation, leading to the Jenkins brand and ecosystem governance by independent contributors and firms including CloudBees. Key milestones include early adoption of the Hudson (software) codebase, formalization of the plugin architecture, and transitions aligning with containerization trends after the popularization of Docker (software) and orchestration by Kubernetes. Jenkins' roadmap has been influenced by interoperability efforts with continuous delivery proponents such as ThoughtWorks and standards groups that shaped pipeline as code conventions.

Architecture and components

Jenkins uses a master-agent architecture where a central controller coordinates work delegated to distributed agents running on diverse platforms like Linux, Windows Server, or macOS. Core components include the controller, agents (formerly slaves), executors for concurrency, and a plugin subsystem. The pipeline subsystem introduced a domain-specific language inspired by scripting models used in Apache Ant and Apache Maven builds. Integration points include APIs that interact with LDAP (directory service), Active Directory, and single sign-on providers such as Okta. For scalability, Jenkins integrates with container technologies like Docker Compose and orchestration platforms like Kubernetes (container orchestration).

Features and plugins

Jenkins features include job scheduling, distributed builds, build pipelines, artifact archiving, and reporting. The plugin ecosystem enables integrations with GitHub, Bitbucket, GitLab, SonarQube, Selenium (software), and artifact repositories such as Nexus (software) and JFrog Artifactory. Pipeline support via the Jenkinsfile DSL allows declarative and scripted pipelines modeled after practices from Continuous Delivery thought leaders. Plugins also provide dashboards that surface metrics compatible with Prometheus, Grafana, and logging systems like ELK Stack (Elasticsearch, Logstash, Kibana). Notable community and vendor plugins arise from organizations including CloudBees, Red Hat, Google, and Microsoft.

Installation and deployment

Jenkins is distributed as a WAR file for use with Apache Tomcat or as native packages for distributions such as Debian and Red Hat Enterprise Linux. Cloud and container deployments are common, leveraging images published by vendors and community members for platforms like Amazon Web Services, Google Cloud Platform, and Microsoft Azure. For high availability and scaling, practitioners combine Jenkins controllers with agents provisioned by cloud providers, or manage ephemeral agents via Kubernetes, HashiCorp Terraform, and Ansible (software). Enterprises often integrate Jenkins with CI/CD platforms from CloudBees or use managed offerings to align with compliance regimes from agencies such as ISO frameworks and corporate policies.

Usage and workflows

Typical workflows automate code compilation, unit testing, integration testing, static analysis, artifact creation, and deployment to staging or production. Pipelines codified in Jenkinsfiles enable branching strategies practiced by teams influenced by GitFlow, Trunk-based development, and pull request workflows from GitHub Flow. Jenkins coordinates test frameworks like JUnit, TestNG, and browser automation via Selenium (software) or Playwright (software). Release automation connects to artifact repositories and deployment targets such as Kubernetes, Docker Swarm, AWS Elastic Beanstalk, and Heroku. Organizations align Jenkins runs with observability tools from New Relic, Datadog, and Prometheus for feedback loops in site reliability engineering influenced by Google SRE publications.

Security and administration

Administration covers user authentication, authorization, credential management, and audit trails. Jenkins integrates with identity providers such as LDAP (directory service), Active Directory, OAuth 2.0 providers like GitHub, and enterprise SSO vendors including Okta. Role-based access control is implemented via plugins maintained by community contributors and companies like CloudBees. Secure plugin vetting, frequent updates, and runtime hardening are recommended to mitigate vulnerabilities documented by vendors and security researchers tracking supply chain risks exemplified by incidents in ecosystems like npm (software registry) and Maven Central Repository. Backup strategies and disaster recovery often leverage artifact stores like Nexus (software) or JFrog Artifactory and infrastructure orchestration from Ansible (software) and HashiCorp Terraform.

Category:Continuous integration