Freelancer profile translated to English.

Description

25 years of experience in operating Linux systems, from own data centers to hyperscaler cloud environments with Kubernetes and containerized microservices. Automation of infrastructure provisioning and CI/CD pipelines. Design and implementation of private PKI for the rollout of mTLS-based authentication – from payment terminals to web applications.

Languages

German
Native or bilingual
English
Fluent

Workplace preferences

Remote only

Primarily works remotely

OC Payment GmbH
Platform Engineer
BANKING AND INSURANCE
June 2021 - January 2026 (4 years and 7 months)
Köln, Germany
• Setup of the Google Cloud and GitHub organization for a corporate startup.
• Infrastructure automation (IaC) with Terraform and Google Config-Connector.
• Implementation of GitOps deployment workflows with FluxCD, Kustomize, and Helm.
• Operation of GKE clusters with various common operators (FluxCD, external-dns, cert-manager, config-connector, stakater-reloader, external-secret-sync).
• Setup and operation of an Observability Stack (Grafana, Mimir/Prometheus, Loki, Tempo).
• Network connection of the existing Poseidon Payment solution via VPN.
• Connection of Worldline Pay (Google Cloud to Google Cloud integration)
• Operation of Ingenico TEM terminal management software.
• Purchase of IPv4 addresses and implementation of a BYOIP solution in Google Cloud.
• Rollout of a Certificate Authority for around 40k payment terminals.
• Introduction of DNSSEC and the use of HTTPS RR as well as CAA RR for securing public connections.
• Setup and participation in on-call duty.
Terraform Kubernetes Google Cloud Platform (GCP) PKI GitOps
REWE digital GmbH
DevOps Engineer
E-COMMERCE
March 2017 - May 2021 (4 years and 2 months)
Köln, Germany
• Operation and further development of the IT infrastructure for shop.rewe.de and
• Scaling of the Docker (dockerd + Nomad + Consul) based platform for ~150 microservices.
• Migration of the entire solution from on-premise to Google Cloud Platform.
• Support and further development of Jenkins-based, team-individual, build & deploy pipelines in a hybrid setup of on-premise and Google Cloud Platform.
• Setup and operation of the central logging infrastructure (Elasticsearch, Logstash, Redis, Kibana).
• Setup and maintenance of Akamai and Cloudflare configuration.
• Setup and maintenance of the automated build infrastructure for container base images (see also FroSCon 2018)
• Debugging of network and Linux system problems.
• Participation in 24/7 on-call duty.
Debian Ansible Nomad Terraform Elastic Stack (ELK)
Net Mobile AG
IT Infrastructure Technical Lead
TELECOMMUNICATIONS
February 2016 - February 2017 (1 year)
Düsseldorf, Germany
• Initiation of an infrastructure-wide migration from CentOS 5 to CentOS 7.
• Implementation of a hybrid cloud operation between Tokyo (AWS) and Frankfurt (own data center).
Linux RedHat cfengine F5 BigIP