Xen Experts in Germany

Development and evolutionary further development of a highly available, cloud-native microservice and integration architecture for dealer and retail processes in the Porsche Car Configurator.

Responsibilities

• Development of Java-/Kotlin-based backend, API, and integration components (Spring Boot)
• Integration of internal and external systems via REST/OpenAPI, GraphQL, Apache Kafka, and AWS SQS (synchronous and asynchronous)
• Implementation of stable, high-performance communication and data flows in a cloud-native platform architecture
• Processing of structured data formats (JSON, Protobuf, GraphQL schemas) based on existing API patterns
• Performance optimization of distributed microservices with reduced response times and higher operational stability
• Technical tests (unit, integration, and API tests) as well as error analysis in production-like environments
• AWS Infrastructure as Code with Terraform and AWS CDK
• CI/CD automation (build, test, and deployment pipelines) with GitHub Actions
• AI-supported feature implementation (GitHub Copilot Agent)

Label: Kotlin, Java 25, Spring Boot 4, Protobuf, TypeScript, AWS, Terraform, CDK, Apache Kafka, AWS SQS, REST/OpenAPI, GraphQL, JSON, PostgreSQL, Docker, GitHub Actions, Maven, Gradle, JUnit, Mockito, Testcontainers

• PRISMA project
• Ansible automation
• Windows third-level support for Windows NT, Windows 2000, Windows 2013, Windows 2016, Windows 2019

• It is like a startup within REWE, where we have to build a new forecasting system on Google Cloud Platform from the scratch. Although, officially my role is called MLOps, my actual tasks also include development of data processing pipelines (data engineering) and data scientists tasks such as feature engineering and model trainings.
• GCP: Terraform (tofu), Vertex AI (Kubeflow), Cloud Run, IAM, Google Cloud Storage, BigQuery, Artifact Registry
• Data engineering: Snowflake as the main data warehouse, Terraform, DBT for data model implementations
• CI/CD: GitLab. We have built a CI/CD pipeline that automates deployments of new releases up to production environment

• Overall coordination of service providers for all infrastructure topics at a production site being set up in Baden-Württemberg
• Design and finding solutions for internet connectivity, building office communication networks, setting up WLAN in production and administration buildings, IP address management, password policies, time tracking, access control systems, backup strategies, emergency power planning, operating concepts, cost planning, event management, workplace setup including laptop/mobile phones/telephony, remote support, print servers
• Selecting suitable external service providers and planning to meet needs for spare parts, repairs, on-site service, network and workplace support including on-site system replacement by providers
• Choosing suitable external service providers for facility management and building technology (fiber optic connections, data center infrastructure, cable ducts etc.)
• Coordination with clients and service providers
• Escalation management, schedule control
• On-site presence for service meetings and managing service providers

• Environment: AWS, Ruby on Rails, GraphQL, React Native
• Penetration test for Backend, Android-App and iOS-App

• Migrate company software to RHEL10
• Development in Bash, Python, C, Ansible

• Recognition of national notified bodies
• Preparation of cybersecurity competency reports
• EU Radio Equipment Directive

• Redesigning cablewise infrastructure with CAT 8.1 keystones, measuring the speed and quality of the new installation with Pockethernet, documentation at a local saddlery
• CAT 8.1 installation and building a data center, site linking, VPN and VLAN configuration for a local car dealership, implementation of IT-Security standards like virus protection (G Data) and firewalling (OPNSense)
• Relocation of a tax office with redesign of the IT infrastructure, virus protection (G Data) and backup solutions (QNAP)
• Planning, conception and implementation of an inhouse data center, BSI-compliant for commercial laundry (including Proxmox-based virtualization of existing infrastructures, QNAP, G Data, OPNSense, APC)
• Implementation and conception of security solutions in the SME sector
• Collaboration on the IT-security concept for the Bremen network of authorities (in the dLAN network)
• Creation of IT-security concept VOIS (modules MESO, KFZ/iKFZ) including audit preparation for KBA
• Expansion of the IT-security concept for the online service for electronic residence registration (eWA) to include use as an eFA (one-for-all) service (nationwide)
• Expansion of the IT-security concept to include modules wos & wvp
• Concept development for the implementation of DIN SPEC 27076 at MSEs and SMEs
• Creation and evaluation of emergency concepts
• Creation and evaluation of response actions and BCM plans
• Assessment of existing business continuity management (ISO 22301)
• Development of BCM strategy options
• Conducting awareness training

• Complete redesign of IT infrastructure including setup of a server room according to BSI standards, new network concept and planning.
• Development of security concepts and IT security consulting for the DHCP/DNS election sector.
• Support of project management for the customer in the VOIS | MESO area.
• Technical support for setting up the IT infrastructure in new offices, including firewall configuration, router setup and network planning.
• Setup and configuration of the service management and ticket system JIRA.
• Implementation and administration of the Azure (Entra) environment for all employees.
• Setup and administration of the Confluence environment.
• Planning, setup, configuration and administration of the entire Atlassian Collaboration Suite.
• Development of BCM strategy options.
• Development and implementation of measures and creation of BCM plans, as well as evaluation of existing BCM.

• Projects for federal networks (NdB).
• CR management, EoL change requests, design and documentation according to ITSCM.
• Data center planning.
• Project management and engineering subproject management.
• Software development for virtual server environments according to BSI.

• Consulted on IT security and process optimization, focusing on NIS2 and risk requirements
• Troubleshot and optimized plant core networks using STP, certified hardware, and open-source components such as OPNsense
• Redesigned network segmentation for VLAN rollout in a hybrid multisite multicloud setup using Tailscale VPN
• Facilitated cross-departmental discussions to align technical and social requirements
• Optimized monitoring with Grafana, Telegraf, and SNMP configurations
• Prototyped network setup for a new plant, including VLAN separation with Tailscale VPN
• Automated various scenarios using Python and Bash scripting

• Planning and documentation of database architecture and integration with other components provided by other teams and vendors
• Extensive documentation for the architecture, security, access control, encryption, roles and user management, backup and restore, disaster recovery and general operations
• Deployment of database clusters over 2 locations with 2 availability zones each
• Automation of deployment and operations including backup using Ansible
• Hardening of the database and operating system
• Migration of existing stand-alone database systems to cluster setup
• Technologies: PostgreSQL, Patroni, etcd, barman, RedHat Enterprise Linux 9 (RHEL), Ansible, Ansible Automation Platform, TLS, Hashicorp Vault, LUKS

• Restructured network architecture/topology and then installed, configured, and tested the network at a small company.
• Fixed server (permissions and roles) and connection issues (WAN, (V)LAN, WLAN).
• Supported and maintained the infrastructure.
• Created documents like manuals, architecture, and design documents.
• Revised manuals and technical documents and created VBA macros.
• Used AI and basic prompting as well as writing AI queries.
• Adjusted workflows to meet legal requirements and improved existing workflows.
• Conducted training and workshops for adjustments, updates, and changed workflows.
• Modeling basis: BPMN.
• System environment: MS Office 2019/365, Win10/11, Teams, Netgear (switch), QNAP, Synology (NAS), Linux (Ubuntu).

• Infrastructure consulting
• Project management
• Mentoring for IT managers & teams
• Management consulting
• Energy data monitoring
• Energy data collection
• Energy data management
• IT system support for Linux, FreeBSD, Windows
• Server operations (incl. monitoring)
• Firewalls & VPNs