Infrastructure Architecture
On-premise and hybrid environments, datacentre platforms and roadmaps built for long-term operation.
Senior IT Systems Architect & Consultant
Infrastructure
for the real world.
I design, build and operate secure, stable and maintainable infrastructure — from architecture to production.
About
Reliable by design.
Practical by nature.
I work across the full infrastructure lifecycle: architecture, implementation, migration, recovery and long-term operations.
My focus spans on-premise, hybrid and cloud environments, virtualization, networks, security, monitoring and automation. I favour clear architecture and predictable behaviour over complexity for its own sake.
Technology is not the goal. It is the tool for creating infrastructure that works.
Expertise
Systems thinking,
from rack to cloud.
Virtualization & Compute
Platform migrations, storage, clusters and resilient compute with recovery built into the design.
Apple, Linux & Microsoft
Apple-certified expertise alongside production Linux, Windows Server, identity and Microsoft 365.
Networking & Security
Segmentation, firewalls, VPN, hardening, TLS/PKI and incident analysis designed in from the start.
Automation & Development
Bash, Python and PowerShell development, CI/CD and infrastructure as code for dependable operations.
Monitoring & Resilience
Actionable monitoring, recovery-oriented backups, tested restores and realistic disaster recovery.
Technologies
Tools chosen
for the job.
The architecture leads. Technology supports it.
Platforms
Proxmox VE · VMware · KVM · Docker · Kubernetes
Systems
Apple · macOS · Linux · Windows Server · Active Directory · Microsoft 365 · Entra ID
Development & automation
Bash · Python · PowerShell · Terraform · Ansible · CI/CD · Infrastructure as Code
Operations
Zabbix · Veeam · Proxmox Backup Server · NGINX · Git
Network & security
Firewalls · VPN · TLS / PKI · Segmentation · Hardening
Selected Work
Complex environments.
Clear outcomes.
Virtualization platform migration
End-to-end transition of production workloads, storage, networking, backup and monitoring from VMware to Proxmox.
Hybrid Microsoft infrastructure
Integration of on-premise Active Directory with Microsoft 365 and Entra ID, including identity lifecycle and services.
Infrastructure recovery
Reconstruction of virtual infrastructure after storage or hardware failure, with backup consistency validation.
Monitoring architecture
Central observability for servers, networks and applications with useful alerting and integrations.
Principles
How I approach
infrastructure.
Stability over novelty.
Newer is not automatically better.
Simple over complicated.
Every component should earn its place.
Security by design.
Security belongs in the architecture, not at the end.
Automation with purpose.
Automate repeatable work, not chaos.
Backup means restore.
Recovery is proven by testing it.
Beyond Infrastructure
Perspective comes
from stepping outside.
Away from infrastructure, you will most often find me in the mountains, on a mountain bike or behind a camera. Hiking, fitness, photography, aviation and drones share the same appeal: technology, movement and a little adventure.
Contact
Let’s build something
that keeps working.
Need an infrastructure consultation, an architecture review or a second perspective on an existing environment?
Emailpetr@kallen.czPhone+420 604 526 123Websitewww.kallen.czAddressnáměstí Odboje 300
544 01 Dvůr Králové nad Labem
Czech Republic
544 01 Dvůr Králové nad Labem
Czech Republic