Experience

Planetly GmbH

Senior Site Reliability Engineer • Feb, 2022 – Feb 2023

  • Management of AWS Cloud Infrastructure with Terraform
  • Planning and Execution of Maintenance Operations affecting production environments
  • Design and Implementation of Terraform CI/CD with CircleCI
  • Containerization of CI/CD Pipelines
  • Integration of Datadog for Alerting and Monitoring
  • Migration of AWS Workloads to Azure

Programming Languages

  • Bash
  • Golang
  • Python
  • Yaml

Tools

  • Ansible
  • CicleCI
  • Hashicorp Terraform

Infrastructure

  • Azure
  • AWS
  • Kubernetes
  • PostgreSQL

Data4Life

Team Lead / Senior Site Reliability Engineer • Oct, 2020 – Oct 2021

  • Management of a four-person Site Reliability Engineering team
  • People and Growth Management
  • Process and Documentation Management
  • Cross Functional Collaboration Management
  • Resource Management and Roadmap Planning
  • Adding a feature to skip uploading a Glance image during an Openstack packer build (upstream)
  • Participation in the re-audit of the German Federal Office for Information Security (BSI) to obtain the ISO 27001 certification

Tools

  • Jira
  • Confluence
  • Slack

Data4Life (formerly Gesundheitscloud)

Senior Site Reliability Engineer • Jan, 2020 – Oct, 2020

The Openstack migration was complete and now it was time to focus on reliability, automation, monitoring, and logging. Focus on improvements for daily operations and recovery.

  • Setup lets encrypt cert manager with ansible
  • Switch to the ansible k8s module instead of the kubectl command
  • Improving the openstack configuration of cloud-init datasource for more resilience
  • Improvement of Grafana dashboards for better visibility
  • Design and implementation of Living Documentation of Openstack resources within Atlassian Confluence using CI/CD
  • Design and implementation to manage PostgreSQL clusters and user accounts using Ansible
  • Design and implementation of sharing Openstack images across different Openstack installations
  • Participation in the re-audit of the German Federal Office for Information Security (BSI) to obtain the ISO 27001 certification

Programming Languages

  • Golang
  • Bash 4
  • Python

Tools

  • Ansible
  • Hashicorp Packer
  • Hashicorp Terraform
  • Hashicorp Vagrant
  • Hashicorp Vault
  • Jenkins

Infrastructure

  • Azure
  • AWS
  • Openstack
  • PostgreSQL
  • Kubernetes

Gesundheitscloud

Site Reliability Engineer • Jan, 2018 – Dec, 2019

Soon after my first few months, we realised that I liked to maintain complex systems like a Kubernetes or database cluster. So I moved from the role of a DevOPS engineer to that of a site reliability engineer. The company caught my attention and the product evolved from a proof of concept to an initial prototype. Given the compliance and security requirements, the company decided to move from a public cloud offering to a private cloud deployment. We evaluated the following two offerings: Microsoft's Azure Stack and Openstack. Initially, we migrated from Azure to Azure Stack and finally, after almost a year, to Openstack.

  • Migration from Azure Stack to Openstack
  • Migration from Azure Cloud to Azure Stack
  • Design and implementation of a Kubernetes API Gateway
  • Integration and maintenance of the Datadog agent
  • Participation in the audit of the Federal Office for Information Security (BSI) to obtain the ISO 27001 certification

Programming Languages

  • golang
  • Bash 4
  • Python
  • Java

Tools

  • Hashicorp Vagrant
  • Hashicorp Vault
  • Hashicorp Terraform
  • Jenkins
  • Ansible

Infrastructure

  • nginx
  • Azure
  • AzureStack
  • Openstack
  • Kubernetes

Hasso-Plattner-Institute

Senior DevOps Engineer • Sep, 2017 – Dec, 2017

My first task was to design and implement Continuous Deployment and Continuous Integration pipelines for our kubernetes microservices platform. The platform was running in Azure and Travis CI was used as a hosted Continuous Integration service.

  • Implementing the Deployment Pipeline for Kubernetes Microservices with Travis CI
  • Design and implementation of core CI/CD pipelines

Programming Languages

  • Bash 4

Tools

  • Hashicorp Terraform
  • Travis CI
  • Helm

Infrastructure

  • Azure

QualityPark

Senior Java Software Engineer • Apr, 2015 – Aug, 2017

The QualityPark company develops, maintains, and customizes the Micro Focus Dimensions RM ( Requirement Management ) solution for enterprise customers. Part of my job was to integrate new features and enhancements into the core Dimensions RM solution. I was responsible for designing, implementing, testing, and integrating Java based components into the core of the Dimensions RM solution. I was the back-end developer on the Java team, along with a front-end developer who did the implementations for the web applications (CSS, HTML, JavaScript). I also did product presentations to clients and provided technical support and feedback.

  • Customer presentation and on-site support
  • Design, implementation and testing of Java components according to CI/CD principles
  • Reverse engineering of core components such as database access and web service APIs from C/C++ to Java
  • Maintenance and troubleshooting of a 20+ year old Dimensions RM solution (C/C++)

Programming Languages

  • Java
  • JavaScript
  • C++
  • C
  • C#

Tools

  • Jenkins
  • Apache Maven
  • Visual Studio Code

Infrastructure

  • Tomcat
  • Oracle Database

Frameworks

  • Apache Jersey
  • AngularJS 1
  • JUnit

ZAG Zeitarbeits-Gesellschaft GmbH

Unskilled Laborer • Sep, 2014 – Feb, 2015

I literally took time off from my job as a developer and decided to work as an unskilled laborer. This brief career change also helped me with my personal development. It improved my attitude towards hard physical work and also helped me lose some weight.

  • 2 months working in a computer retail warehouse
  • 1 week working as a waitress at the InnoTrans 2014 trade fair.
  • 1 week work as a furniture packer for offices
  • 1 month work in a warehouse for shoes

Self-employed

Open Source Developer • Aug, 2013 – Sept, 2014

Programming Languages

  • JavaScript
  • Scala
  • Java

Tools

  • Travis CI
  • NodeJS

Infrastructure

  • Heroku

Frameworks

  • AngularJS 1
  • Apache Wicket
  • NodeJS

Deutsche Post AG

Senior Java Software Developer • Mar, 2013 – Aug, 2013

I worked on the Partner B2C API team. We were responsible for designing and developing an API for the EPost Brief product. The development department was organized according to the Agile Scrum methodology. The release process was done together with the Operations department. The team was responsible for deploying a working Puppet configuration and the rollout was performed by the Operations department.

  • Design and implementation of the Rest API services for B2C partners

Programming Languages

  • Java
  • Groovy

Tools

  • Gradle
  • Teamcity

Infrastructure

  • Jetty

Frameworks

  • Grails

AdClear GmbH

Senior Java Software Developer • Mar, 2011 – Oct, 2012

The company AdClear GmbH was founded in March 2011. In the same month, I was hired as a Senior Java Software Developer to lead the web application development from the beginning. The company had about 8 permanent employees at that time. I already knew most of them from my time at the zanox AG. My job was to design the web application along with the related backend services. Later that year, a frontend developer was hired. He was a fresh student who I brought on board as a mentor.

  • Design and implementation of Map Reduce (based on MongoDB), analytics and reporting services.
  • Design and implementation of web services for data access.
  • Design and implementation of a web application for the analysis of e-commerce customer journeys

Programming Languages

  • Java
  • JavaScript

Tools

  • Apache Maven
  • Jenkins

Infrastructure

  • Tomcat
  • MongoDB
  • Root Server

Frameworks

  • Apache Wicket
  • Apache CXF

AWIN AG (formally zanox AG)

Senior Java Software Developer • Aug, 2006 – Feb, 2011

Hired as a working student to develop a web application using Microsoft C++ based on the cgi interface of IIS 6. Completed the exam and got hired as a Java Software Developer. 2006 - 2010 Migrated core services from a legacy system developed in C/C++ to Java Platform Enterprise Edition. 2010 - 2011 Technical lead of the Public WebServices team to build a highly scalable public REST /SOAP API.

  • Development and maintenance of a public API
  • Research and development of zanox connect (authentication and authorization)
  • B2B and B2C integration with Web Services (Soap and Rest)
  • Design and implementation of core services with SOA (Service Oriented Architecture)
  • Migration to the Java platform, Enterprise Edition
  • Reverse Engineering of the legacy system (C++ PRM)

Programming Languages

  • Java
  • C++

Tools

  • Apache Maven
  • Jenkins

Infrastructure

  • JBoss 4
  • Tomcat
  • memcached
  • lighttpd
  • MSSQL

Frameworks

  • Hibernate
  • Apache CXF
  • Apache Lucene

Total

Internship • Nov, 2003 – Feb, 2004

During my studies of Applied Computer Science at the HTW (former FHTW) Berlin I did an internship at the company Total. The project of this internship was the development of an e-commerce like web application for internal use.

  • Automation of internal web statistics report generation
  • Development of an internal E-commerce like shop for oil related products

Programming Languages

  • Perl

Education

Fachhochschule für Technik und Wirtschaft Berlin HTW (formerly FHTW)

Diploma, Applied Computer Sciene • 2001 - 2006

Skills

Mentorship

I have several years of experience in leading and mentoring people and organizations.

Software/System Architecture

With over 15 years of experience in software development. I have developed a sense of reasonable good and bad architecture. In my opinion, a reasonably good architecture requires that the technical and non-technical requirements are known in advance. In most cases, the communication structure of a company is also reflected in the software/system architecture, especially when it is developed and implemented by multiple teams (Conway's Law).

Improvement Potential

Work Principles

After reading the book 'Principles' by Ray Dalio. I was inspired to put together my personal working principles.

Meeting

Don’t take the time and attention of work colleagues for granted.

They have to be valued and earned constantly.

Be clear at the start of a meeting. What is the meeting about and for who ?

Change

The power of change and adaptation.

Starts with yourself

Efficiency

Just work Smart.

Don’t repeat over and over the same discussion and conversations. Break repeating cycles they are mostly number one time consumers.

It's all about the ratio of time and outcome.

Tools / People

Tools have to follow people and not the people the tools.

The number one priority of tools is to help people to be more productive and save time instead of cost time.

If tools are not in line with point a) then drop them or replace them with another tool.

Leadership

It’s not about you.

Focus has to be on the people to lead.

Help them to grow.

It’s all about you.

Be authentic and lead by example.

Don’t expect more from others then from yourself

Outside Interests

  • beach volleyball
  • science and technology
  • books
  • leadership