Hi, I’m Holger Kühn

Computer scientist with 40 years in IT – from the mainframe to my own homelab. Retired today, but as curious as ever.

Technical background

From Assembler and Fortran to C, C++, Go and Java, I’ve worn many hats: application developer, systems engineer, consultant and Senior Solution Architect. Over the decades I’ve worked with clients like DHL, Deutsche Post, Lufthansa, Volkswagen and the Deutsche Bundesbank. My credentials include VMware vExpert, MCP and Oracle DBA.

Entrepreneurship

I ran my own business for many years, specializing in server and application virtualization – including contracts through VMware.

Since 2024

Officially retired – but still keeping two long-time clients happy with IT support. Technology doesn’t let go that easily.

My homelab

A multi-site setup built around UniFi networking, Proxmox virtualization and ZimaOS (ZimaCubes & ZimaBoards) for NAS and Docker workloads. In use: a Zimaboard 1, a Zimaboard 2 and a ZimaCube 2. Everything exposed securely via Pangolin, Gerbil and Traefik on a Hetzner VPS, hardened with CrowdSec and interconnected through a WireGuard mesh. I’ve worked with ZimaOS actively for over two years – both at a client and on my own systems.

Community

As an active ZimaOS contributor I build apps, tools and MCP integrations for the IceWhale ecosystem. You’ll find me on GitHub as chicohaager and in the community (Discord & IceWhale) as Lintuxer.

Hobbies

AI development – and flying single-engine aircraft.

Traces from the past

Online for a long time: thinapp.wordpress.com and josil.de, once an Oracle forum with more than 1,000 users.