Jenkins VPS — Self-Hosted Jenkins
CI/CD Server

The Basic plan ($7/mo, 2 GB DDR5 RAM) handles Jenkins LTS with light to moderate build load. Jenkins Java process uses 256-512 MB RAM. The Professional plan ($14/mo, 4 GB) is recommended for parallel Docker builds and teams running 5+ concurrent jobs.

Jenkins LTS itself uses 256-512 MB RAM for the controller. Each Docker build agent uses additional RAM depending on the build. For parallel builds on a 4 GB VPS: allocate 1 GB to Jenkins controller and 1 GB per concurrent Docker build agent.

A Jenkinsfile defines your entire CI/CD pipeline in Groovy DSL — build, test, deploy stages, parallelism, error handling, and notifications. Stored in your Git repository, versioned with your code, and reviewable in pull requests. Pipeline configuration becomes part of your codebase, not hidden in Jenkins UI.

Install Jenkins Docker Pipeline plugin. Add the Jenkins user to the docker group (`usermod -aG docker jenkins`). In Jenkinsfile, use `agent { docker { image "node:20" } }` to run build stages inside Docker containers. Use `docker.build()` and `docker.push()` for image builds.

Enable Jenkins security: Manage Jenkins → Security → Security Realm (Local/LDAP) and Authorization (Matrix-based). Configure Nginx reverse proxy with HTTPS. Disable HTTP port 8080 directly. Enable CSRF protection. Install Role Strategy Plugin for fine-grained permissions.

Choose Jenkins when: you need complex pipelines beyond GitHub Actions' YAML capabilities, you have many build minutes/month (Jenkins at $7/mo vs $0.008/min), you need the 1,800+ plugin ecosystem, you have compliance requirements preventing cloud CI, or you need fine-grained access control across many teams.