Linux Expert in Stuttgart

• Development and introduction of operations processes
• Preparation of complete documentation packages (including incident management and operations support) to meet compliance requirements
• Introduction of a workshop on IaC (Infrastructure as Code)
• Technical consulting for the project security concept (ISMS)
• Installation and operation of Kubernetes clusters on AWS, on-prem, and Azure
• Hybrid cloud architecture design (on-prem, Hetzner, AWS)
• Analysis and troubleshooting of incidents and system outages
• Network adjustments for firewall rules, gateways, OpenVPN settings, and IPsec tunnels (pfSense)
• Technical consulting on Bitbucket, Jenkins, and GitLab CI/CD pipelines
• Consulting on Ansible deployments and infrastructure automation
• Consulting on building a scalable system in the cloud (AWS / Azure)
• Technologies / Tools: Ansible, Terraform, AWS, Azure, VPN, pfSense, Jenkins, Bitbucket, Kubernetes, GitLab Runner, ISMS, Golang, Prometheus, Grafana, S3, Lambda, RDS, ECS, Cognito, OIDC, Harbor, MinIO, Postgres, Redis, Keycloak, Ceph, Proxmox, CloudFormation, PostgreSQL, Flux CD, Hetzner, IONOS, Sonatype Nexus Repository, Entra ID, Dex IdP, Pulumi

• Situation: Increasing demand for privacy-compliant AI solutions for clients in the KRITIS and mid-market sector that need to analyze sensitive media content (audio, video, documents) without sending data to public cloud LLMs.

• Task: Design, deployment, and secure operation of a fully self-hosted AI infrastructure including a custom-built digital management platform for automated media analysis.

• Action: Architected and implemented a multi-tier platform on hardened Proxmox infrastructure with frontend (Nuxt 3, Vue 3, TypeScript, Tailwind 4), backend (Laravel 13, PHP 8.4, Sanctum), data storage (PostgreSQL 16, MongoDB 7), caching/queuing (Redis 7, Laravel Queue), AI workers (Python 3.11, Whisper, DeepFace, Librosa), scheduling (Laravel Scheduler/Cron), and local LLMs (Gemma, DeepSeek, Qwen, Mistral, LLaMA, Phi) via OpenWebUI with segmented network access, API hardening, and audit logging following BSI recommendations.

• Result: Fully GDPR-compliant, on-premises AI platform with zero data leakage to third parties.

• Task: Overall responsibility as an external Head of Cyber Security / CISO-as-a-Service for the design, implementation, and continuous improvement of ISMS according to ISO 27001, BSI IT-Grundschutz, and NIS2.

• Action: Built and managed Cyber Defense Centers (CDC) with SOC operations, integrated SIEM solutions (Splunk, Graylog), established risk-based vulnerability management (Qualys, Nessus, OpenVAS), and conducted regular infrastructure, application, and physical penetration tests.

• Result: Audit-ready ISMS for multiple clients and a 60% reduction in critical vulnerabilities within 90 days.

• Task: Design and execution of NIS2 assessments and operational roll-out plans for KRITIS operators.

• Action: Developed an online assessment tool for automated identification of individual weakness profiles, implemented ISMS optimizations, penetration testing, awareness programs, GRC suite deployment, and delivered C-level presentations.

• Result: Accelerated the consulting process by 50% and successfully prepared multiple clients for NIS2 compliance.

• Task: Incident commander for crisis response, forensics, and business recovery in ransomware attacks and APT campaigns.

• Action: Coordinated with state and federal police (LKA, BKA), performed forensic analysis (OSForensics, Wireshark, Kali Linux), executed disaster recovery and BCM strategies, and developed BTC extortion response strategies.

• Result: 100% recovery rate within defined RTO windows and sustainable post-incident security architectures.

• Action: Planned, built, and operated a hardened multi-VM infrastructure (Proxmox, 15+ VMs) with web and mail servers, Graylog, OPNsense firewalls, CRM/ERP and LLM instances, network segmentation, DDoS mitigation, automated patch management, and backup strategies.

• Result: >99.5% uptime over 20+ years and zero compromises.

• Action: Designed coordinated phishing campaigns with five levels of difficulty, developed e-trainings and webinars in a PDCA cycle, and led red and blue teams.

• Result: Phishing click rate reduced from 35% to under 5% within three campaign cycles.

Designed and developed an AI-powered automation platform using n8n to analyze social media niches, identify target audiences, and automate marketing strategy generation. The solution combined AI agents, workflow orchestration, and data analysis to automate research processes and generate data-driven insights.

• Designed and implemented complex automation workflows using n8n
• Developed AI-powered analysis agents for market and audience research
• Integrated multiple APIs and AI services into automated workflows
• Built automated market, competitor, and target audience analysis pipelines
• Leveraged Large Language Models (LLMs) for information summarization, classification, and prioritization
• Containerized and deployed the platform using Docker

Technologies: n8n, AI Agents, OpenAI APIs, Prompt Engineering, LLMs, Docker, Linux, REST APIs, Webhooks

• Developing the infrastructure and improving existing infrastructure: Jenkins, Gitlab Pipeline, OpenShift, Docker, Helm Chart, Kubernetes, Artifactory, CodePipeline, CodeArtifact, Python
• Documenting solutions in Jira/Confluence
• Supporting other colleagues in different technical areas

• Development of a SaaS platform for esports teams with roles, scheduling, statistics, and billing
• Planning and implementation of the architecture, external API integrations, and operations
• Stack: Laravel 13, React 19, TypeScript, PostgreSQL, Redis, and Stripe

• System administration of FreeBSD 11, 12 and 13.1 in a secure cloud software solution
• Administration of proxy servers for FITS and its clients, banks and state banks
• Administration of secure internet solutions
• Administration of secure mail solutions and mail gateways
• Administration of Apache 2.4 web servers
• Planning and maintenance of servers and network components in FNT Command
• Incident, change and ticket handling, especially troubleshooting network issues using Splunk and ARS
• Troubleshooting and log file analysis using Splunk Enterprise
• Monitoring with Nagios
• Ordering, provisioning and installation of certificates on Apache web servers, Nginx web servers and load balancers
• Hardware: HP ProLiant DL380 Gen 9 and 10, Cisco Catalyst
• Software: FreeBSD 11, 12 and 13.2, FNT Command, shell scripts, MySQL databases, ServiceNow, ARS, Splunk Enterprise 8.15

• Support of test management and consulting on replacing the existing core system for non-life insurance with a modern IT platform.

• Planning and controlling test execution as well as test analysis.

• Documentation of test results in JIRA/XRAY and defect management.

• Creating and continuously updating checklists to ensure quality.

• Creating Confluence pages to support test execution and its documentation.

• Creating test completion reports after each test cycle.

• Methods: process planning, status tracking, process optimization, process execution, process quality assurance.

• Tools: MS Office, Outlook, JIRA, Confluence, Wiki.

• Benefit: Support for test management in the preparation, execution and documentation of the different test cycles.

• Develop hardware drivers and middleware using C++11, Java and Python
• Design of various RF features such as deembedding based on stakeholder requests
• Work with multiple teams to design drivers for multiple RF products
• Perform HW control to deliver RF signals and measure modulated response
• Develop RF drivers for generation of low noise signals to test WiFi7 products
• Use digital modulation techniques such as QAM for low level driver development
• Develop low level USB drivers for device enumeration
• Develop drivers for HW relay control of control boards for device testing
• Perform JTAG operations on devices under test
• Use network-based protocols (SFTP, UFTP, FTP, SSH) for control board communication
• Manage HW devices such as BADC and EEPROM for control board maintenance
• Utilize C++11/14/17 features, template metaprogramming and STL
• Employ multithreading for testing and control of multiple HW devices
• Develop tools for deployment of customer OS on control boards
• Perform component and integration tests using CxxTest
• Follow Scaled Agile Framework for software development
• Create detailed design documents using PlantUML

• Consulting, design, analysis, software architecture and development
• Designing, developing, and implementing a Pimcore environment and connecting multiple external API systems in a Kubernetes environment, as well as various PIM and ERP systems
• Technologies: Unix environment, design, Symfony development, PHP 8+, software architecture, MySQL/SQL, shell scripting, Git DevOps tasks, AI coding support, Pimcore 12, Shopware 6
• Team size: >10 people

• Implementing applications with Kotlin and Ktor as microservices
• Using MongoDB in the MongoDB Atlas cloud
• Asynchronous communication of services via Google Pub/Sub
• Using Kotest and MockK for unit tests
• Developing an administration frontend with TypeScript, React and Express.js
• Provisioning environments in GCP using Terraform
• Implementing CI/CD processes with GitHub Actions
• Operating scalable production and test environments in GCP with Kubernetes, Helm and Flux CD
• Monitoring environments with Prometheus and Grafana
• Providing BI data in the Google BigQuery data warehouse

• IT Senior Consultant (bank infrastructure, Active Directory, Azure, security, PKI)
• Planning, design, and implementation of cloud solutions based on Microsoft Azure / M365
• Teams, M365, and cloud services
• Vulnerabilities, threats, attacks
• Security analysis, security policy, security architecture
• Conducting meetings and presentations at various management levels
• Organizing and leading team meetings to improve internal communication
• Tools: PowerShell, Active Directory, GPO, DNS, DHCP, scripting

• Designing the migration strategy for WLS applications to the BKA cloud and Stack IT

• Creating a hybrid cloud for internal testing and development with Kubernetes

• Transforming the IT landscape from a legacy monolithic architecture to a cloud-based architecture

• Integrating new CI/CD processes using Azure Pipelines

• Quadrupled the throughput of personnel security checks

• Migrated personnel security clearance applications to Docker-based applications

• Built CI/deploy pipelines with Azure DevOps

• Environment: Java Spring Boot, Kubernetes, Oracle WebLogic, OpenID, Camunda, JUnit, TOGAF

• Development of a new generation of Spring Boot microservices for an archiving system on OpenShift, monitoring, security analyses

Stack: Java, Spring Boot, Kafka, Vaadin, OpenShift 4.x, Maven, Artifactory, Jenkins, Git/Github, GitHub Copilot, GitOps, CI/CD, Kargo/ArgoCD

• Investigating the PoC and replacing and refining an existing cloud and IoT power plant control solution for certificate management of renewable energy plants (solar, wind, biomass, etc.) for the largest European renewable energy network operator, including examining the field IoT devices and their integration and network connections, aiming for automated PKI key management.
• Messaging with Kubernetes for large API-connected enterprise applications
• Risk and attack vector analysis, software quality & bug assessments
• Agile workload scheduling via Jira & Confluence
• Evaluation of pub/sub message streams for MQ and Kafka.
• Various tests with “best design approaches” for resilience patterns like circuit breaker designs, throughput measurement and monitoring, bulkhead governors – for robust EA design
• Integration of API management with IBM's API Connect to Kubernetes for platform-agnostic microservices API management designs. Google Apigee
• Solution health check approaches for load burst situations + remedy
• Research and evaluation of potential sub-service providers in the coordinating role as solution manager. CIS20 controls.
• DREAD and STRIDE security assessments.