Dockerized Jenkins cluster for VM provisioning

Problem

New VM provisioning ran through a single, hand-maintained Jenkins controller with no isolation between jobs and no easy way to scale build capacity when several provisioning requests landed at once.

Approach

I designed a Docker-based Jenkins cluster with isolated and globally spread agents, then chained it to Terraform for infrastructure definitions and Ansible for post-provision configuration. Provisioning requests started to run end-to-end without manual handoffs between tools.

Impact

• Provisioning time dropped to 15 minutes, down from a multi-hour manual process.
• Build agents are isolated per job, removing a whole class of “works on the controller” bugs.
• The same automation approach was later extended to DKIM key renewal for Postfix servers, cutting that task’s runtime under 5 minutes.