Jenkins

Jenkins is the grandfather of CI, but still widely used in enterprise. In 2025, it runs primarily as Code (Jenkinsfile) and often on Kubernetes.

When to Use

• Legacy/Enterprise: You have massive, complex, custom requirements that only Jenkins plugins can handle.
• Fineness of Control: You need absolute control over the build environment.
• On-Premise: You cannot use Cloud CI.

Quick Start (Declarative Pipeline)