Denis Urek Platform / DevOps Engineer

1. Training-registration platform

   Sole owner: app, database, admin UI, workers, CI/CD, deployment

   • Python
   • RabbitMQ
   • MySQL
   • GitLab CI/CD
   • Docker

   Customers and alumni register for training deliveries here. It was a mostly static JSON site, hand-edited by one person for every new event, field and description, so every admin change queued behind a single engineer.

   Outcome

   Replaced the static files with a database and a self-service admin UI, so staff create and edit events and manage sign-ups themselves. Reports now generate automatically, four per event covering attendees, filtered lists and waitlists, which took an estimated several hours a week of manual compilation off the admin team. The v2 rebuild put sign-ups, invite emails and calendar events behind a RabbitMQ queue, so a failed job returns to the queue and is retried rather than lost. Carries an estimated ~10,000 registrations a year.

2. Delivery pipelines and infrastructure as code

   Designs and maintains

   • GitLab CI/CD
   • Docker
   • Ansible
   • Terraform
   • Grafana

   Internal tools and customer-facing apps both need the same thing: a repeatable path from a commit to a hardened, running service.

   Outcome

   GitLab pipelines build and deploy containerized services onto security-hardened Linux VMs, with Ansible or Terraform chosen per stack rather than by default. Grafana runs across the production VMs I own, scraped by an internal collector across a firewall boundary.

3. Configuration data automation

   Built and shipped

   • Python
   • Claude Code
   • Internal web UI

   Server and switch configuration arrived as Excel workbooks running to roughly ten thousand lines, and somebody had to translate them into JSON by hand.

   Outcome

   A web-accessible automation parses the workbooks, maps them to JSON and pushes the result into a master-configuration app, removing a slow and error-prone manual translation step for large network-device datasets.

4. Internal Kubernetes development cluster

   Built and operated it, then retired it

   • Kubernetes
   • Rancher
   • Linux

   I was the Kubernetes-certified engineer, so I built and ran the internal Rancher-based development cluster.

   Outcome

   It served as the internal development platform until the storage overhead, resource cost and dedicated-staff requirement stopped paying for themselves at a service-focused company, so I retired it. Genuine operational Kubernetes experience, and deliberately not presented as production I run today.

5. Hands-on technical training labs

   Subject-matter expert and author

   • OpenShift AI
   • Kubernetes
   • Linux
   • Networking

   Certification training needs labs people actually run, not slides they read.

   Outcome

   Roughly 25–30 guided labs authored across major certification-training programmes, covering OpenShift AI, Kubernetes networking with Cilium and Tetragon, Linux hardening, and agentic AI development. I also proctored the Capture The Flag at Cisco Live Amsterdam 2025.

6. Applied AI in the delivery workflow

   Organization owner of Claude Code

   • Claude Code
   • Anthropic API
   • MCP
   • Python

   Content-delivery work was slow, and the quality drifted depending on who reviewed it.

   Outcome

   I administer Claude Code for the organization and advise colleagues on adoption and tooling. Writing my own delivery workflow against a golden-example spec took one recurring task from about five days down to about one, with more consistent output. That figure is my own estimate for that task, not a company-wide measurement.

Public and self-hosted

• Steam Workshop Monitor Open-source Discord bot that watched Steam Workshop items for updates. Built to solve my own problem: I needed to know when a mod changed so I could roll it out before it broke a session on the server I ran. Reached around 100 servers, the pre-verification ceiling, with users writing in for help. Early code, kept here as an origin story rather than current best work. Source
• Telegram-to-Discord bridge Relay that forwards Telegram messages into Discord channels. Source
• Homelab, since 2021 A personal server running VMs and containers, with monitoring and alerts, a media stack the family actually uses, and single sign-on added for an app sitting behind a reverse proxy. The same end-to-end ownership as the work above, at my own expense.
• This site Static, dependency-free, no build step, served from an nginx container on the homelab above. No analytics, no cookies, no third-party requests. How it was built

1. Jan 2023 – Dec 2023Ljubljana Junior DevOps / Software Engineer Flint SI

   • Designed and implemented CI/CD pipelines for internal services.
   • Led development, deployment and maintenance of internal tools and services.
   • Built infrastructure using infrastructure-as-code practices.
   • Onboarded with Cisco NSO for telecom development.
2. Jan 2022 – Dec 2022 Freelance Developer Independent

   • Built Python automation tools and Discord bots, including an open-source Steam Workshop monitor that reached roughly 100 servers.
   • Ran a homelab on VMware and Docker. It still runs today, and this site lives on it.
   • Wrote CI/CD pipelines and administered Linux servers.
   • Built Arma 3 mods in SQF for the community server I ran; explored Cardano NFT minting.
3. May 2021 – Oct 2021Slovenia IT Student Spletina d.o.o.

   • Computer servicing, repair and IT support.
   • VMware virtualization, basic networking and WordPress maintenance.
   • First hands-on time with a physical server box, the start of the homelab habit.
4. 2017 – 2022 Arma 3 community server operator Self-directed

   • Rented and provisioned a Hetzner dedicated box (Windows Server) and ran a heavily modded Arma 3 platform solo: initial setup, the mod set and its update rollouts, keeping every client in sync, and ongoing maintenance.
   • Twice-weekly operations with 30–40 concurrent players, sustained for about five years.
   • Also ran a self-hosted TeamSpeak 3 voice server and Discord bots supporting the group.
   • Began four years before my first paid IT role, and produced the Steam Workshop monitor above.

Credential badges are verifiable on LinkedIn.