André Bürger
DE

André Bürger

IT Systems Administrator

Windows · Linux · Monitoring · Security · Automation

Itzehoe, Germany

I design and manage reliable IT infrastructure—from Active Directory and network segmentation to monitoring, security, automation, and backup. I work in a structured and well-documented manner, always keeping the big picture in mind. Open, transparent communication, calm coordination in complex situations, and clean, reliable implementation are particularly important to me.

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André Bürger
Troubleshooting Structured & solution-focused
Coordination Prioritisation & ownership
Communication Clear, calm, reliable

Expertise

Skills & Tech

Microsoft / Cloud

Windows ServerActive DirectoryDNS / DHCPMS 365Entra IDIntuneAutopilotMicrosoft Cloud PKI

Virtualisation / Containerisation

VMware vSphereProxmox VEDocker

Network & Security

pfSenseSophosNetBirdVLANs

Monitoring & Observability

CheckmkGrafanaGraylogWazuhTactical RMMUptime Kuma

Scripting & Automation

PowerShellBashAnsiblen8nSemaphore

Tooling & Services

Atlassian CloudJira Service ManagementConfluenceGitLabNextcloudAuthentikMailcow

Career

Experience

Systems Administrator

DRS Deutsche Retail Services AG, Wilster, Germany

08/2023 - present current

Focus on internal infrastructure across three locations, supplemented by assistance with deployment and support, as well as the coordination and prioritization of incoming requests.

  • Responsibility for internal infrastructure at 3 locations
  • Infrastructure coordination, including ticket triage, assignment, and prioritization of incoming requests and incidents
  • Internal infrastructure projects and support for requests and incidents from staff
  • Operation of monitoring, network, security, and backup systems
  • Operation and further development of monitoring, network, security, and backup systems
  • Occasional assistance with deployment and support

Apprenticeship, IT Systems Integration Specialist

PERITS GmbH, Wilster, Germany

08/2020 - 07/2023

Three-year apprenticeship with broad hands-on focus across IT infrastructure.

  • Final project: router/firewall replacement (Lancom → pfSense), VLAN segmentation, VPN migration
  • Deployed Active Directory (Windows Server) as central identity management
  • Rolled out Jira Service Management (migrated from VISOMA)
  • PBX migration from NFON to Starface, ongoing administration

Work

Selected Projects

Infrastructure Support Portal

Jira Service Management

Problem

Requests arrived uncontrolled through many channels, with no overview and no prioritisation.

Solution

Designed and rolled out a centralised JSM support portal as the mandatory intake channel for all teams.

Result

5-10 tickets/day in steady state. Full transparency over open cases and analytics for all stakeholders.

Monitoring Migration

Icinga → Checkmk

Problem

Purely reactive troubleshooting, poor visibility, issues only noticed at failure.

Solution

Full migration from Icinga to Checkmk, complete rebuild of the monitoring stack.

Result

Approx. 100 hosts and 2,000+ services monitored. Proactive detection, faster troubleshooting cycles.

Customer Download Portal

Nextcloud

Problem

Many historically grown ways of delivering files to customers, confusing and error-prone.

Solution

Planned, tested, and rolled out a hosted Nextcloud instance as a unified standard for all customers.

Result

Actively used by all customers. Single, standardised channel for upload and download.

Personal

Homelab

A production-grade learning and test environment. Everything is documented, segmented, maintainable, and recoverable, with concepts that translate directly to professional environments.

3

Proxmox Nodes

44

CPU Cores

320 GB

RAM

25+

Services

3

Sites

3 PBS

Backup Servers

Architecture

  • Multi-site Active Directory with 2 DCs at separate locations and site-aware DNS resolvers
  • pfSense firewalls at 3 sites, site-to-site IPsec (routing- and policy-based)
  • 10 GBit core with LACP, VLANs & DMZ design, 36U rack with UPS
  • SSO via Authentik (OIDC/SAML), Linux login via SSSD against Active Directory
  • 3-2-1 backup: 3 PBS instances, TrueNAS Cloud Sync, Hetzner Storage Box (encrypted)
  • Full observability stack: Checkmk, Grafana, Graylog, Wazuh

Services

Platform, Storage & Containers

Proxmox VETrueNAS SCALEDockerCloudpanel

Monitoring

CheckmkGrafanaGraylogWazuhUptime Kuma

Identity & Access

Active DirectoryAuthentikSSSDNetBird

Automation

n8nSemaphoreTactical RMM

Apps & Services

NextcloudGitLabMailcowPaperlessHome Assistant

Network

pfSenseUnifiPangolinNginx

Get in touch

Contact

I'm not actively job-hunting - but if you have a concrete offer or just want to talk shop, I'm happy to hear from you. Preference: fully remote or on-site in the Itzehoe area.

mail@andrebuerger.de
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