Marcus Wiederstein – Knowledge, Architecture, and Delivery at the Comelio GmbH Competence Center

I am an IT expert in Linux, networks, virtualization, and Kubernetes—with a clear focus on architecture, automation, and precision. As a knowledge worker with delivery expertise, I work hands-on with systems, carefully document my knowledge, and constantly acquire new skills.

My goal is to pass on expertise and help teams and individuals develop their professional skills.

I place great value on technical depth, transparency, and sustainability—always with the aim of creating more knowledge, more clarity, and more structure.

I work for Comelio GmbH, which was founded as a center of excellence for IT. In addition to hands-on project work, we focus on knowledge transfer—both in ongoing projects and in the form of specialized seminars with highly qualified instructors, many of whom are authors of technical books.

Sharing and imparting knowledge is a central part of our work. That’s why we offer support in the form of “competence calls,” in which we analyze and solve IT problems together with our customers. We have deliberately decided against classic service level structures – and recommend suitable partners when needed.

Location

My office is located in Comelio GmbH’s own seminar center – just a few minutes’ walk from Ruhr University Bochum, in a quiet area. It has fiber optic internet and ultrawide monitors with split function. The high-quality equipment and access to modern AI tools, other assistants, and numerous learning platforms enable concentrated work and continuous further training. The workplace is perfect for remote work and also has excellent transport links.

Basic Linux administration skills

I have been working in administration for more than 20 years.

Distributions: Debian · Ubuntu · RHEL · Oracle Linux

Skills: Systemd · LVM · Identity Access Management · Crontab · Shell · SSH · Journalctl

Certifications

I continuously expand my expertise through practical training and official certifications in the areas of Linux, Kubernetes, and cloud infrastructure. My focus is on stable, secure, and automated environments.

In addition, I work intensively with container technologies such as Docker and open-source databases such as PostgreSQL and MariaDB.

Thanks to my many years of experience with Oracle databases, I also handle migrations from Oracle systems to modern open-source platforms.

Current and planned certifications:

  • Certified Kubernetes Administrator (CKA) – in preparation
  • Certified Kubernetes Application Developer (CKAD) – planned
  • Certified Kubernetes Security Specialist (CKS) – planned
  • Linux Professional Institute Certification (LPIC-1) – completed
  • Linux Professional Institute Certification (LPIC-2) – completed
  • LPIC-3: Security – in preparation
  • EDB Certified PostgreSQL Professional (EnterpriseDB) – planned
  • Red Hat Certified Engineer (RHCE) – planned

Key topics:

Networks, Kubernetes cluster administration, containerization with Docker and virtualization with KVM, Proxmox VE, GitOps automation, container security, Linux hardening, and DevOps CI/CD pipelines.

Roles in projects

As an IT architect and open-source consultant, I perform the following tasks as a systems network specialist and cloud/security expert:

  • Infrastructure & Networks: Planning, implementation, and operation of Linux server infrastructures as well as network design and administration.
  • Virtualization & containers: Virtualization of complete environments and support for applications deployed with Kubernetes, Docker, or KVM.
  • Databases & migration: Design, administration, and optimization of relational databases, as well as planning and execution of migrations from Oracle to PostgreSQL or MariaDB.
  • Knowledge transfer: Training courses and workshops on networks, open source, Linux, virtualization with Kubernetes, Docker, and KVM, as well as various databases, servers, and service applications.

Professional liability & cyber insurance (Hiscox)

As part of my work as an IT consultant, I have comprehensive professional liability and cyber insurance through Hiscox.

For me, this is a natural part of my role as a responsible consultant: it protects my clients and ensures the highest possible security and professionalism in projects involving sensitive data and critical infrastructure.