System Engineer ·

Skills

Hypervisor & Virt.
Proxmox VE KVM HA Clustering
Operating Systems
Linux FreeBSD
Automation
Ansible Puppet Bash Scripting Python
Monitoring
Nagios Observium Icinga Grafana LibreNMS
Networking
Fortigate OPNsense DNS DHCP SSL/TLS VPN (Wireguard, tinc) BSI Compliance
Containers
Docker (Compose) Container Networking
Data & Storage
PostgreSQL MySQL Ceph
DevOps
Git Infrastructure Design Performance Tuning

Experience by Area

Monitoring & Observability
Linux / Systems Admin
Virtualization (Proxmox/KVM)
Automation & Scripting
Networking & Firewalls
DNS & Certificate Mgmt
Project Leadership

Scale: — · Based on professional practice since Sept 2019

Hospitality Project 2025

Customer Takeover — Remote Project Leadership

Took over full project leadership for a critical 20-location hospitality portfolio 1100km away. Remote-only operations with fallback on-site technician support. Led comprehensive off-season maintenance covering security audits, OS updates, network core infrastructure upgrades, and DHCP optimization across all sites.

18 Maintenance windows executed
22 OS updates deployed
7 Locations DHCP pool adjustments
6 Components Critical infrastructure updated

Key Initiatives

Security Audit Remediation

Implemented findings from comprehensive security audit across network management systems.

High Priority · Weeks 43–44

OS Update Campaign

Deployed security patches and firmware updates across Windows Servers, FreeRADIUS, and monitoring stack (Debian 12 → 13).

8 Systems · Weeks 44–45

Network Core Upgrade

Modernized switching infrastructure including Catalyst 9300, Nexus 9000, and wireless controller updates.

Weeks 45–49 · High Impact

DHCP Pool Optimization

Analyzed and expanded DHCP pools across 20+ zones. 10+ pools operating at >80% capacity, standardized lease time configurations.

Weeks 49–51

VPN & Connectivity

Upgraded firewall and VPN infrastructure with focus on Zagreb data centre on-site deployment and testing.

Multi-week engagement

Monitoring Standardization

Unified monitoring across Nagios, Observium, and Grafana with Debian-based VPN gateway upgrade.

Infrastructure Foundation

Work

2026 — Highlights

Q1 2026

Major Retail Client — Content Filter Rollout 400+ Markets

Converted 50% of store branches (400+ markets) to centralized content filtering. Executed on-site testing during early morning deployment window. Planned and scoped the expansion from 2 to 4 filter nodes, including DHCP configuration adjustments across the entire market infrastructure.

Content Filtering DHCP Network Operations Retail Infrastructure

2025

Q4 2025

Hospitality Customer Takeover — Project Lead Remote Leadership

Took over project leadership for a major 1100km+ remote hospitality account. Responsible for scoping, coordination, and delivery of critical infrastructure tasks (Cisco switching, core network upgrades) across 20+ locations. Remote-only operations with fallback on-site technician support. High-criticality coordination managing complex upgrade schedules and off-season maintenance windows.

Project Management Remote Operations Network Infrastructure Critical Systems
Q2 2025

SMTP Edge Mailrelay — Rebuild & Rollout

Rebuilt the SMTP edge mail relay from scratch to enable email alerting for UPS systems, Proxmox hosts, and other infrastructure components that had previously lacked outbound mail capability.

SMTP Mail Infrastructure Alerting
Q2 2025

Retail Client — Network Switch Upgrade On-site

On-site infrastructure upgrade of switching equipment across distribution centres: migrated network switches to higher-speed hardware. Executed in collaboration with client-side engineers during a Saturday maintenance window.

Network Switches Hardware Upgrade Retail Infrastructure
Q1 2025

PVE Cluster Upgrade Wave — AAC / FFM Proxmox 6 → 9

Planned and executed a full multi-site Proxmox upgrade wave across production clusters in AAC and FFM zones. Each upgrade was performed in a ~6-hour overnight maintenance window to minimise guest disruption. Rolled from Proxmox VE 6 all the way to version 9 across all nodes.

Proxmox VE HA Clustering Multi-site Change Management
Q1 2025

Hospitality Client — USB Device Automated Rollout (15 Sites)

Designed and implemented an automated system to attach and deploy hardware dongles across 15 hotel sites via Proxmox VE. Eliminated the need for individual manual device passthrough configuration at each site, reducing deployment time significantly.

Proxmox VE Device Passthrough Automation Hospitality
Q1 2025

Hospitality Client — VM Migration Standardisation

Developed the migration guide and workflow for Proxmox VM migrations across a multi-site hospitality environment. Defined the deployment feedback loop and standardised the process for team reuse.

Proxmox VE VM Migration Documentation
Q1 2025

DNS Operations — Infrastructure-wide

Assumed responsibility for all DNS-related changes across the infrastructure from early 2025 onward. Handles BSI-mandated IP and domain redirect requests, with focus on compliance and operational excellence.

DNS BSI Compliance Network Operations

2024

Q1 2024

Hotel Client — Recurring On-site Missions On-site

Multiple on-site deployment and maintenance missions at a boutique hotel property across 2024 and 2025. Covered network infrastructure, server maintenance, and system-level work directly on location.

On-site Operations Hospitality Infrastructure Multi-visit Engagement

Ongoing — Since 2019

2019 →

Monitoring Infrastructure — Nagios & Observium

Primary owner of the monitoring stack across multi-zone enterprise infrastructure. Manages Nagios alerting and Observium network visibility for the full infrastructure portfolio. Covers threshold tuning, check development, and escalation workflows.

Nagios Observium Alerting Network Visibility

Side quests

Q4 2025

lazyink.de — Tattoo Studio Homepage

Hand-crafted static website for a tattoo studio in my hometown. Simple, elegant design showcasing portfolio and booking information. Built from scratch with a focus on clean typography and smooth user experience.

HTML/CSS Responsive Design Web Design
Q4 2025

Defensio Toolkit — no402.com

Comprehensive toolset for the nocy.io privacy cryptocurrency ecosystem. Built a dynamic mining leaderboard tracking $DFO miners in real-time, a universal Docker one-shot installer supporting MidnightMiner, DefensioMiner, and FetcherBot, and a live API status + wallet statistics dashboard.

Python Docker Compose API Integration
45+
Proxmox VE Nodes
3-node clusters & standalone
30+
Nagios Nodes
Alerting & check automation
15
Observium Nodes
Network visibility & SNMP polling
200k+
Services Monitored
Across all Nagios instances
14k+
Hosts Under Watch
Active SNMP & agent-based
20+
Remote Locations
Hospitality portfolio, 1100km+
4
Data Centers
2 on-site · 2 remote