PROFESSIONAL EXPERIENCE

Ministry of Defence [Feb 2023 – Present]

  • Build cyber and cognitive defensive capabilities
  • Lead a team designing, developing, and maintaining technical systems
  • Set technical direction and grow engineers through mentoring and training
  • Design and run cyber exercises with realistic technical and information-operation scenarios
  • Focus on resilience, clarity, and long-term operational effectiveness

At the Czech Ministry of Defence, I work on building cyber and cognitive defensive capabilities in an environment where assumptions are challenged and failure has real-world consequences. My role sits at the intersection of systems engineering, security, and strategy: translating abstract threats into concrete, dependable technical solutions.

In addition to hands-on technical direction, I lead a team responsible for designing, developing, and maintaining these solutions. A significant part of my work is growing people: setting technical direction, mentoring engineers, and ensuring continuous training. I also design and prepare cyber exercises, combining deep technical scenarios with information-operation storylines to simulate realistic conditions. The goal is not just to build systems, but to build teams that can think, adapt, and operate effectively under pressure.

Red Hat, Senior Software Engeneer [Jan 2011 – Feb 2023]

  • Kernel engineer in the Red Hat Kernel / File Systems team
  • Core contributor and maintainer of the ext4 file system and jbd2 journaling layer across all RHEL releases
  • Maintainer of e2fsprogs and quota for RHEL and Fedora
  • Upstream-focused development: feature design, bug fixing, and long-term backporting into RHEL
  • Deep cross-subsystem work spanning VFS, block layer, and memory management
  • Regular presenter at international conferences (Kernel Summit, LSF/MM, DevConf) and university courses
  • Mentor for junior engineers, interns, and university students working on theses

As a member of the kernel and file systems team, I worked primarily on the ext4 file system and related user-space utilities. My responsibilities included debugging customer issues, fixing bugs, developing new features upstream, and backporting upstream code into Red Hat Enterprise Linux (RHEL).

Over the years, I became a maintainer of the ext4 file system as well as the jbd2 journaling layer across all RHEL releases. I also maintained e2fsprogs and quota for both RHEL and Fedora.

My work in the Linux kernel often extended into closely related subsystems such as VFS, the block layer, and memory management. Occasionally, I ventured into other parts of the kernel when investigating file system issues whose root causes ultimately lay elsewhere—one recent and particularly interesting example involved a CPU firmware bug.

Beyond core engineering, my role at Red Hat included presenting my work at international conferences (Kernel Summit, LSF/MM, DevConf, etc.) and delivering lectures in an Operating Systems course at a local university.

Although I never held a formal team lead position, I mentored junior engineers and several interns at Red Hat. I also served as a technical advisor for multiple students working on their Bachelor’s and Master’s theses at local universities.

WebStep, system Administrator [Mar 2008 – Dec 2010]

  • Assisted system administrators with day-to-day operations
  • Created and managed mailboxes and web hosting accounts
  • Registered and maintained internet domains
  • Installed, configured, and maintained servers
  • Set up and administered network and application services

I assisted system administrators and handled routine operational tasks, including creating mailboxes and web hosting accounts, registering domains, installing and maintaining servers, and configuring and managing services.

PROJECTS

Here is a list of the most interesting publicly available projects I have contributed to. As these are open-source projects, my work is freely available for anyone to review. Most of my contributions were made under my Red Hat email address lczerner@redhat.com. Links to the public project repositories and selected contribution statistics are included as well.

EDUCATION

Brno University of Technology - Faculty of Information Technology [2008 - 2010]

  • Computer Systems and Networks
  • Master’s Degree
  • Thesis: Porting of RedirFS on Other OS

Brno University of Technology - Faculty of Electrical Engineering and Communications [2003 - 2008]

  • Teleinformatics
  • Bachelor’s Degree
  • Thesis: Scripts for configuration of Fedora operating system in PlanetLab

ABOUT ME

I’m a systems-focused software engineer with over a decade of experience contributing to the Linux kernel, including long-term work in core subsystems such as file systems. My background in low-level infrastructure shaped a strong bias toward correctness, performance, and resilience in real-world conditions. In recent years, I’ve shifted from purely deep technical work toward leading teams, mentoring engineers, and multiplying impact through knowledge transfer. I currently work at the Czech Ministry of Defence on cybersecurity and defensive capabilities, operating in adversarial environments where robustness is non-negotiable. My interests span operating systems, cybersecurity and cognitive security, with a particular focus on the invisible infrastructure that underpins modern society.

SKILLS

  • Programming: C, Bash, Python, automation
  • Systems: Linux kernel, File Systems, Docker, Ansible