Open Source Specialist

Trainings

Over the past 20 years, I have been offering trainings on open source, networks, and databases – all based on real-world experience and the latest technology. My portfolio includes:

• Linux administration: from the basics to professional server operation, including shell scripting, permissions management, and troubleshooting.
• Network security with OPNsense: planning and configuration of firewalls, VPN solutions, and security concepts for companies.
• Container and cloud technologies: Workshops on Docker, Kubernetes, and OpenStack – from container orchestration and clustering to the setup of private cloud infrastructures.
• Automation with Ansible: Introductory and advanced training on infrastructure as code, playbook development, and automated deployments.
• Mail & collaboration solutions: Setting up and operating email systems with Postfix and Dovecot, spam and virus protection with Rspamd/ClamAV, and collaboration platforms with SOGo and mailcow.
• Databases & migration: Administration and migration of Oracle systems, as well as design and operation of PostgreSQL and MariaDB databases.

Books

In addition to my work as an IT architect and network specialist, I have published several specialized books on SQL Server, XML, Oracle, Java, and PHP. This background knowledge in databases and programming now feeds into my role as an administrator, network, and Kubernetes specialist: it helps me to understand complex systems in their entirety and to seamlessly integrate solutions at all levels—from databases to container orchestration.

My first books in the year 2000 dealt with XML and databases. They were published by Rheinwerk (formerly Galileo Computing), Addison Wesley, and mitp.
In addition, there are my two- and six-page quick references. The two-page ones were popular in IT training for many years.

Through our in-house specialist publishing brand Comelio Medien, I plan to publish specialist books on Kubernetes and PostgreSQL in the future. As I am simultaneously expanding my certifications in Kubernetes, cloud security, and databases, balancing writing projects and further training is a challenge—nevertheless, my goal remains to pass on my expertise in book form.

Projects

I assist companies with the planning, implementation, and hardening of complex IT infrastructures—from the initial concept to stable, continuous operation.

• Analysis of existing system and network architectures
• Migration from VMware to KVM/Proxmox or OpenStack
• A/Gatekeeper
• Setting up CI/CD pipelines and DevOps automation with Ansible, Bash, Python
• Database migrations (Oracle → PostgreSQL, MySQL, MariaDB)
• Integration of security mechanisms (SELinux, TLS, OpenSCAP, VPN hardening)
• Documentation and knowledge transfer in Markdown / Bookstack

Competence Call

Flexible expert support without lengthy project contracts – ideal for short-term or specific issues.

• Troubleshooting for Linux, network, or storage problems
• Remote analysis of Kubernetes deployments or Docker stacks
• Support for CI/CD errors or Ansible playbook adjustments
• Security checks, log analyses, and system hardening
• Code or infrastructure audits (e.g., for PostgreSQL, Kubernetes, Ceph)
• Ad hoc knowledge transfer or mini-training via screen sharing

Trainings

Pass on technical know-how that can be applied immediately in everyday work – with fully virtualized Linux lab environments.

• Kubernetes: Cluster setup, Helm, Kustomize, GitOps, security
• Docker & containerization: Best practices, troubleshooting, CI/CD integration
• Ansible & infrastructure as code: Automation, roles, templates
• Hands-on training via browser-based Guacamole system – no local setup required
• Open source platforms: OpenStack, Proxmox, Ceph storage, WireGuard
• Security & compliance: SELinux, AppArmor, OpenSCAP, TLS management
• Databases: PostgreSQL administration, high availability, migration