Fullstack Developer, DevOps-Engineer, Dozent DevOps

My first time at Groundkeeper was limited due to the budget that was tight to that time. This was
communicated beforehand and thus I was assigned a very specific and isolated task:
I built an application to administrate the data that was used for the actual application. That way
Groundkeeper employees could validate posts and fix incurred data generated by the users.
For this to work I had to create migrations step by step using ecto and phoenix framework to end up with




an identical database scheme which then enabled me to implement the admin panel using elixir and
phoenix. The application was a huge success and is still in use today.

Responsibilities

- Implementation of an admin panel using Phoenix framework and Elixir

- Gradual transition of Sequelize migrations to Ecto migrations to ensure compatibility

- Maintenance and extension of the Web-socket API in the backend

- React frontend development

- CI/CD testing and deployment of the admin panel into staging & production



Tools and Technology

PostgreSQL, Elixir, Phoenix framework, Ecto database library, Docker, docker-compose, Javascript, CSS,
Linux, Bash scripting, HTML, Tests

This was my first full-time job and also my first experience in a start-up. The CEO and owner of that
company bought 2 servers for the internal infrastructure and it was my responsibility to create and
maintain VMs using vSphere ESXI where I deployed all Software we needed to operate.
For this I dockerized the complete Atlassian Software stack (jira, confluence, bitbucket) and deployed into
the VMs. Configuring and maintaining the Sophos UTM Firewall was partly my responsibility as well.

The software we were developing was using the PostGIS extension which to this time had to be built
manually before usage. I created a Dockerfile which automates this process. I implemented a terminal
solution where Intel NUKs were used as terminals from which the user could logon to an available VM.
The user's home folder was mounted remotely using Kerberos authentication. To ensure predictable and
unique user ids I used SSSD. All VMs and hardware maintained as inventory via Ansible for which I wrote
the configuration files.
Due to the simple fact that most developers hired there were geoinformaticians with no background in
web-development my task was also to supervise and mentor those colleagues to use the tooling and to
basically lern web-development.
I took part in writing a backend that processes pictures taken by a mobile app which then georeferences
given picture for later validation. It was intended to be used in the field by experts for ammunition
defusing and disposal. This was a collaboration between an external IOS developer and Braune Digital
GmbH.

Responsibilities

- PostgreSQL deployment in Docker

- PostGIS deployment

- Ansible maintenance of VMs and hardware




- SSSD-Auth for Linux clients

- Integration of Jira, Confluence and Bitbucket into corporate IT

- Configuration of CI/CD pipelines

- Creation of Linux VMs for FOSS services.

- Sophos UTM

- Backend development in NodeJS and PHP Symphony

- VMware ESXi administration

- Docker image creation and deployment

- Mentoring junior developers

Tools and Technology

Docker, Linux, SSSD, ActiveDirectory, Kerberos Authentication, vmWare vSphere ESXI, Sophos UTM
firewall, Bitbucket, Jira, Confluence, nodeJS, PHP, Symphony framework, Ansible, Bash scripting

I stared my career as a freelance web-developer during college. I worked at several small companies and
was exclusively programming in PHP.
The first small projects were Facebook apps like quizzes or landing pages for pixel GmbH. Then I worked
some weeks in Hamburg at Facelift bbt GmbH which needed some support for their inhouse marketing
software, which also was Facebook focused.
After that I worked some years at Ehe und Janneck GmbH & Co. KG. I finished a project what my
predecessor left dysfunctional. I had to periodically import/synchronise data form a SOAP api provided by
a third party company which holdes information for the public to be looked up. The project was a module
inside a Zend-Framework and was called ZuFiSH (Zuständigkeitsfinder Schleswig-Holstein).
I basically had to reverse engineer the relations of given entities of the SOAP api into a database scheme
in order to cache the result locally and not to query the SOAP api every time which was extremely slow.
I succeeded in fixing broken page request (due to timeout of the SOAP request) and using the local
database as cache. In the end I finished the synchronisation process which removes, created or updates
entities according to the state of the SOAP data.
In that time I was also doing small tasks for Webzap UG.

Responsibilities

- Data migration from SOAP interface

- Working on a custom CMS based on ZendFramework

- Development Facebook apps/games