Jeroen – DevOps, Python, AWS

LibrePlan is an open-source web application for project planning, resource allocation and progress tracking, used by client organizations to manage their projects. Its large codebase had fallen several major platform versions behind and lacked a modern, automated release process.

• Migrated the ~300k-line codebase from JDK 8 through JDK 11 and 17 to JDK 25 (Jan – Jul 2026), bringing the application onto a current, supported runtime;
• Used AI (Claude) to speed up rewriting database queries in the business-object layer, reviewing and verifying every generated change;
• Designed and implemented a Forgejo-based CI/CD infrastructure covering builds, release management and publication of new versions;
• Leads the open-source project: coordinates development, works directly with client organizations and helps them adopt the software

The Netherlands’ national knowledge and training institute for fire services, crisis management and disaster response. Its internal infrastructure ran on an aging configuration-management setup and an end-of-life operating system, with significant accumulated technical debt.

• Led a DevOps team of 3 engineers, prioritizing and steadily reducing a large backlog of technical debt;
• Managed the migration from Puppet to Ansible, starting with an automated conversion of PuppetDB data into Ansible inventory;
• Researched and managed the migration of servers from CentOS 7 to RHEL 9, automated with Ansible;
• Launched a Kubernetes (K3S) proof of concept, with AWX as the first application running on the cluster;
• Responded to security and failure incidents, prioritizing service restoration

A Dutch implementation partner for open-source business software. Organizations running many open-source tools usually make users keep a separate login for each one, and this project created a reusable, automated way to connect them all to one central identity system.

• Built a set of reusable Ansible playbooks that install and configure single sign-on for 10 popular open-source applications against one central identity provider;
• Connected applications including Jenkins, GitLab, Nextcloud, Odoo (CE 14 and 15), XWiki, Zabbix and CMDBuild;
• Designed the identity layer on Keycloak combined with FreeIPA;
• Kept the playbooks simple and production-ready, as baselines other engineers could reuse and extend;
• Presented the results at CfgMgmtCamp 2023

An energy-tech startup that builds devices measuring residential power consumption and turns the collected data into a web-based dashboard for its users. The company ran its platform on rented physical servers with no monitoring and no backups, so outages could go unnoticed and its data had no safety net.

• Took ownership of systems management for the startup’s production platform running on 5 physical Ubuntu servers;
• Set up application and infrastructure monitoring with Zabbix, giving the company visibility into server and application health for the first time;
• Built a reliable off-site backup solution, syncing data to Amazon S3 with Rclone;
• Delivered additional infrastructure features on request and monitored the platform’s day-to-day health;
• Advised the company on its future infrastructure and technical direction