Nils M. - Database Architecture for PostgreSQL

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Offenburg, Germany

Experience

Jan 2024 - Present

1 year 8 months

Berlin, Germany

Database Architecture for PostgreSQL

ComputaCenter / Deutsche Rentenversicherung Bund

In this project the customer is moving all services to a newly built geo-redundant data-center in two locations. Since the DevOps infrastructure has some components requiring PostgreSQL, an RDBMS not formerly used by this customer a plan for the architecture of PostgreSQL cluster had to be designed and implemented.
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.

Aug 2023 - Dec 2023

5 months

Migration from AWS to Hetzner

Wonder Tech Sp. z o.o.

Wonder Tech provides an e-Commerce platform primarily for businesses selling furniture online internationally. The project involved migrating the infrastructure from AWS to dedicated bare metal Servers at Hetzner, performing the migration without downtime and reducing costs by over 80%.
Consulting regarding replacement of proprietary AWS components with Open Source alternatives.
Consulting and assistance with automating deployment of services on Hetzner using Ansible.
Database Migration for MariaDB / MySQL using replication.
Analysis and resolution of performance issues through the whole stack.
Technologies Used: Ansible, Ubuntu Linux, MariaDB / MySQL, node.js, nginx.

May 2023 - Aug 2023

4 months

Hamburg, Germany

PostgreSQL Cloud Migration

mrge Group GmbH / shopping24

Shopping24 develops tailored e-commerce solutions for product recommendations. The scope of the project was twofold: Assess the current state of the database systems and ensure working backups as well as high-availability and prepare the existing databases for migration to AWS.
Ensure working backups with barman and pgbackrest.
Create replicas for databases using pgbackrest.
Prepare existing servers for migration to AWS using pglogical and DMS.
Use ansible to manage the on-prem infrastructure.
Migrate databases from on-prem to AWS RDS using logical replication.
Database performance optimization post-migration.
Consulting regarding Instance sizing and product selection for cloud based database.
Technologies used: PostgreSQL, CentOS, barman, pgbackrest, Ansible, GitHub, git, AWS, RDS, pglogical, logical replication, Terraform, Prometheus, Grafana.

Feb 2023 - Aug 2023

7 months

Develop Image builder for Whitebox Switch

InsidePacket Inc.

This project involved building a solution to create Debian Linux images that are automatically installed to an x86 / Broadcom Jericho2 based switch. The image is built using ansible and contains a custom kernel as well as proprietary software to manage the switch running in a Docker container.
The image is built once via a GitLab pipeline and can be installed to the switch via DHCP boot or through ONIE over the local network without requiring internet access.
Technologies: Ansible, Debian Linux, GitLab, Docker.

Feb 2022 - Aug 2022

7 months

PostgreSQL Database Automation

K-Mail Order GmbH & Co. KG

This project concerned the returns processing of the company for its own shops as well as third parties, the total scope of the project was a migration from a mainframe based legacy system to a new system based in Java Applications with PostgreSQL as a database running on a mix of CentOS, RHEL and Ubuntu Linux Vms.
Develop Ansible Roles for managing PostgreSQL instances.
Automated Testing of Roles using molecule as well as GitLab CI.
Database migration and major version upgrade using pglogical replication.
Database backup with wal-g.
Consulting on database table structure and performance optimization.
PostgreSQL Monitoring and Alerting with Icinga.
PostgreSQL Log shipping to ElasticSearch using fluentd.
Technologies: PostgreSQL, wal-g, pglogical, GitLab, git, icinga, fluentd, ElasticSearch, Ansible, molecule, gitlab-ci, CentOS.

Nov 2021 - Jun 2023

1 year 8 months

Berlin, Germany

PostgreSQL Database Consulting SRE Team

IONOS SE

IONOS offers cloud computing made and based in Germany with a particular focus on GDPR compliance. PostgreSQL is a central piece of the infrastructure for the cloud solution.
Consulting regarding database structure and performance.
Plan for database upgrade and new, HA setup.
Backup and Restore of databases / tables with barman.
Infrastructure automation with Ansible.
Transfer of database responsibilities to another internal team.
Maintaining Postgres Clusters running on Debian Linux.
Database Monitoring with Prometheus/Thanos and Grafana.
Technologies: PostgreSQL, Barman, Patroni, etcd, Proxmox, Prometheus, Grafana.

Jan 2021 - Oct 2021

10 months

Germany

Consultant PostgreSQL Database

IBM Germany – “e-Rezept” project

The “e-Rezept” project is part of the digital transformation of the German healthcare sector. This project concerns the handling of prescriptions for medication digitally, planned to handle hundreds of millions of digital prescriptions per year from issuance to billing.
Work on database design, choice of appropriate table structure, data types and partitioning for a multi terabyte database including encrypted data.
Python scripting for data expiration.
Assist in High-Availability setup planning.
Technologies used: PostgreSQL, repmgr, barman, Python 3, RHEL 8, IBM Cloud.

Jan 2020 - Oct 2021

1 year 10 months

Berlin, Germany

PostgreSQL Database Automation

Ratepay GmbH

Ratepay offers tailor-made payment solutions for online merchants and marketplaces. The focus of this project was to improve the various databases used to run the business.
Migrating applications from EXASOL to PostgreSQL.
Automating setup of PostgreSQL Clusters.
Setting up highly-available PostgreSQL Clusters using Patroni.
Optimizing SQL Query performance for applications.
Migration of a mission-critical PostgreSQL cluster from BDR2 to BDR3.
Developing backup solutions.
Automating maintenance and setup tasks with Ansible.
Technologies used: PostgreSQL, Patroni, 2nd Quadrant BDR, Consul, VMWare ESXi, Ansible, Terraform, git, Debian Linux, HAProxy.

Nov 2019 - Dec 2019

2 months

Heusenstamm, Germany

PostgreSQL Database Automation

ITSG GmbH

ITSG provides IT services (Hosting and Development) for German statutory health insurance (gesetziche Krankenversicherung). The project involved setting up PostgreSQL databases for the CI/CD, Collaboration and Automation platforms for a project.
Capacity planning for database servers.
Backup Concept.
Automation Code in Ansible.
Streaming Replication with repmgr.
Backup with barman.
Technologies used: PostgreSQL, Ansible, RedHat Enterprise Linux (RHEL) 8, VMWare ESX, Barman, RepMGR, git (gitlab).

Sep 2018 - Jan 2019

5 months

Düsseldorf, Germany

Consultant – Performance / Reliability Engineering

Parfürmerie Douglas GmbH

Successfully assisted the customer in preparing their complex e-Commerce site for Black Friday, achieving 100% availability in a high-revenue, business-critical phase.
Performance Analysis, Load Testing, Configuration review.
Making recommendations and applying to the production code and configuration.
Technologies: Java/Scala/JVM, SAP Hybris, Tomcat, InfluxDB, Grafana, Graylog, ElasticSearch, Sensu, StormForger, nginx, HAProxy, SaltStack, proprietary components (Prudsys, FactFinder).

May 2018 - Aug 2018

4 months

Hamburg, Germany

Consultant – Operations Engineering

ABOUT YOU GmbH

Maintaining, Extending and Troubleshooting LEMP (Linux, Nginx, MySQL, PHP) applications (Laravel / Lumen) running on AWS.
Developing Ansible roles for use with packer for creating Amazon Machine Images (AMI).
Assisting in database migration from EC2 Instances to AWS RDS.
AWS cost optimization (scaling policies, instance sizing).
Onboarding new employees onto the Infrastructure as Code environment.

Nov 2017 - Mar 2018

5 months

Berlin, Germany

Consultant – Database Administration

Zalando SE (Pricing & Forecasting)

Optimizing of legacy database infrastructures based on MySQL and complex stored procedures.
Migration of ETL processes from Bash scripts / Stored Procedures to Python, Airflow and docker.
Preparation of database migration to PostgreSQL on AWS.

Aug 2017 - Jul 2018

1 year

Bielefeld, Germany

Consultant – DevOps Engineering

OEDIV KG

Writing comprehensive Ansible playbooks for installing various applications (Atlassian Stack, Owncloud, LAMP) on virtual machines on premises as well as AWS and Azure.
Troubleshooting Java Applications (Atlassian stack).
Building a CI Pipeline for Ansible playbooks on Gitlab.

Mar 2017 - Jul 2017

5 months

Hamburg, Germany

Consultant – DevOps Engineering

ABOUT YOU GmbH

Assisting in Migration to AWS.
Creating CloudFormation Templates.
Moving Databases to AWS RDS.
Creating and upgrading ansible playbooks.
Troubleshooting of Problems with MySQL databases, Redis Key Value Stores.
Assisting Teams in troubleshooting PHP (Laravel/Lumen) based Applications.

Summary

A technology and open source enthusiast since young age, driven and self-directed, 100% self taught. Enjoys debugging and Troubleshooting as well as new Development. Pragmatic and iterative approach. Versed in Cloud deployments as well as on-prem and hybrid.