Andreas Steffan

Lead Developer

Hamburg, Germany

Experience

Sep 2023 - Mar 2024
7 months
Hamburg, Germany

Lead Developer

Software

Prototyping CMIS adapter for document management system

Skills: Azure, Terraform, Azure DevOps, Azure Container Apps, Azure Monitor, OpenTelemetry, Docker, TestContainers, Spring Boot, GraalVM, OpenAPI, Cucumber

  • Extended the document management system with a standard CMIS (Content Management Interoperability Services) interface
  • Implemented CMIS core services such as navigation, access rights, search, CRUD operations, and versioning in Java
  • Built on RESTful / OpenAPI services
  • Delivered as a fat-jar and native container image
  • Deployed on-premises and serverless as an Azure Container Application with Terraform
  • Improved team autonomy through infrastructure engineering and short feedback loops
  • Observability with OpenTelemetry, Azure Monitor, and Azure Logic Apps
  • Introduced Terraform and trunk-based development processes
  • Quality assurance with BDD tests implemented in C# using SpecFlow and Testcontainers
  • Azure DevOps pipeline integration tests
  • Established cloud deployment processes
  • Conducted cloud and Terraform training for staff
  • Secret ingredient: coffee as an integral part of the development process
Mar 2023 - Apr 2023
2 months
Hamburg, Germany

Lead Developer Chaos

Public Sector

Prototyping chaos engineering

Skills: Kubernetes, LitmusChaos, Argo Workflows, GitOps, Flux, Terraform, Istio, Kube-Prometheus Stack, Loki, Nix

  • Built a chaos engineering environment with LitmusChaos
  • Implemented observability with the Prometheus stack
  • Created chaos workflows with Argo Workflows for two applications to gain basic understanding of chaos engineering
  • Introduced disturbances: latency and service outages
  • Ultimate goal: improve application resilience.
Nov 2022 - Sep 2023
11 months
Hamburg, Germany

Lead Developer/Architect

Insurance

Established OpenShift environments with GitOps change processes on-premises

Skills: vSphere, OpenShift, Kubernetes, GitOps, Argo CD, Terraform, Nix, GitLab, Datadog, AWS ECR

  • Designed on-premises OpenShift (OKD) Kubernetes cluster environments
  • Declarative provisioning on vSphere using Terraform, Argo CD, and Nix
  • Security-driven isolation of environments (sandbox, dev, int) with separate subnets per cluster
  • Integrated Argo CD and Terraform with one Argo CD instance per cluster
  • Provided Terraform execution environment through Nix
  • Observability with Datadog and Prometheus stack
  • Provided image registry via AWS ECR
  • Staff training
Sep 2022 - Oct 2022
2 months
Hamburg, Germany

Lead Developer Continuous Delivery

Food

Implemented GitOps processes on AWS, Kubernetes, and Terraform

Skills: AWS, Kubernetes, Amazon EKS, GitOps, Flux, Terraform, GitHub, Slack, Datadog, Traefik, Amazon SNS/SQS

  • Designed and implemented GitOps deployment processes for AWS EKS-based microservices using Flux and Terraform
  • Kubernetes integration with AWS IAM
  • Implemented continuous integration pipelines with GitHub Actions
  • Integrated Flux with Terraform
  • Asynchronous inter-service communication via AWS SNS and SQS
  • Connected third-party shop catalog eventing via AWS EventBridge
  • Implemented observability with Datadog
  • Slack integration for alerting and deployment events
  • Implemented service mesh with Traefik Enterprise
Apr 2022 - Jul 2022
4 months
Hamburg, Germany

Lead Developer Cloud Infrastructure

Warehouse Technology

Implemented GCP infrastructure and landing zones

Skills: GCP, Terraform, GitOps, Azure DevOps, Go, ClojureScript, Cloud Functions

  • Designed and implemented GCP infrastructure as part of a multi-cloud strategy
  • Designed and implemented landing zones
  • Implemented deployments with Azure DevOps and Terraform
  • Implemented alerting via MS Teams using ClojureScript
  • Implemented serverless tagging with Go
  • Staff Terraform training
Jun 2021 - Apr 2022
11 months
Hamburg, Germany

Lead Developer Cloud/Continuous Delivery

Retail

Greenfield setup for continuous delivery and infrastructure

Skills: GCP, GKE, Kubernetes, Terraform, Flux, GitOps, GitHub Actions, Apache Solr, Apigee, Clojure(Script), Spring Boot, Kotlin

  • Designed and implemented GitOps change processes for Kubernetes and GCP resources
  • Enhanced team autonomy through infrastructure engineering
  • Implemented GitOps for Solr resources using Clojure/ClojureScript
  • Implemented index feedback via machine learning
  • Continuous integration with GitHub Actions
  • Operated Solr via operator
  • Deployed across three stages
  • Implemented k6 load tests for Black Friday and the Super Bowl
  • Alerting via OpsGenie, Google Operations, and MS Teams
  • Integrated Prometheus with Google Operations metrics
  • Implemented fast recovery (criticality) via rebuild/restore/reindex
  • Implemented search read cache with GCP Redis
  • Implemented canary migration with Apigee
  • Staff training in Terraform, Kubernetes, and operations
Mar 2021 - Jun 2021
4 months
Hamburg, Germany

Lead Developer Continuous Delivery Kubernetes ETL

Finance

Set up continuous delivery for Apache Airflow

Skills: GCP, GKE, Kubernetes, GitHub Actions, helmfile, GitOps, Apache Airflow, Apache Spark

  • Deployed on Google Kubernetes Engine (GKE)
  • Designed and implemented continuous delivery for Apache Airflow/Spark workloads
  • Initially implemented continuous delivery with helmfile, then with Flux
  • Implemented CI with GitHub Actions
Jan 2020 - Feb 2021
1 year 2 months
Hamburg, Germany

Platform Engineer

Logistics

Built a cloud platform

Skills: GCP, Open Telekom Cloud, OpenShift, Kubernetes, Terraform, GitOps, Jenkins X platform, Helm, Skaffold, Draft, Docker, GitLab, Nexus, Docker Registry, ChartMuseum, Monocular, Git, GitLab CI, Prometheus, Elasticsearch, Fluentd, Kibana, Python, Go, Clojure

  • Established a platform team to relieve feature teams
  • Improved application lead times
  • Deployed and managed various Kubernetes clusters: OpenShift PaaS, Kubespray + Ansible, Telekom CCE
  • Covered disciplines including observability, authentication/authorization (SSO), networking, key management, storage, databases, CI/CD, messaging
  • Greenfield build of GCP infrastructure with Terraform, Cloud Build, and GitLab
  • Recovered from a major datacenter incident over a holiday weekend in shifts with a war room
Jul 2019 - Jan 2020
7 months
Hamburg, Germany

Developer/Infrastructure Architect

Mechanical Engineering

Cloud migration and decommissioning on-premises infrastructure

Skills: AWS, Azure AD, vSphere, Office 365, Terraform

  • Planned and decommissioned branch vSphere on-premises infrastructure and applications
  • Designed and built infrastructure and applications on AWS and Azure
  • Migrated services: file service, business applications, terminal servers, Exchange mail server, Netscaler ADC, Veeam Backup
  • Migrated VPN
  • Built AWS IAM, EC2, Route 53, S3, Lambda, SES, CloudWatch, AWS Backup
  • Integrated Azure Active Directory identity provider with MFA
  • Set up Office 365 services
Jan 2018 - Jun 2019
1 year 6 months
Hamburg, Germany

Lead Developer Kubernetes Infrastructure

Finance

Built a cloud-native platform on-premises

Skills: Kubernetes, GitOps, Jenkins X, Helm, Skaffold, Draft, Docker, Jenkins, Nexus, Docker Registry, ChartMuseum, Monocular, Git, Prometheus, Elasticsearch, Fluentd, Kibana, vSphere, Go

  • Designed and implemented a highly available and scalable on-premises consumer document archive platform with Kubernetes
  • Evaluated numerous cloud-native solutions in a short time
  • Established a CI/CD process following GitOps principles
  • Selected and configured storage, networking, and observability components
Sep 2017 - Feb 2018
6 months
Hamburg, Germany

Lead Developer Document Management Platform

Finance

Implemented a consumer document archive

Skills: Alfresco, Java, Spring, OpenAPI

  • Designed and implemented a headless consumer document archive for multiple millions of users based on Alfresco Content Services and OpenAPI
  • Developed functionality for lifecycle, users, metadata extraction, search, transformations, and access control
Aug 2014 - Oct 2014
3 months
Hamburg, Germany

Lead Developer Content Management

Education

Introduced personal documents online campus

Skills: Java, Alfresco Platform, Spring, Solr, CMIS/REST services, Freemarker, JavaScript, YUI, Java Swing, Groovy, Spock, Maven, MySQL, Git, Yeoman, Grunt, Bower, npm, AngularJS

  • Designed and implemented management of personal documents (exams, applications, certificates) for students and faculty in an online campus of a university
  • Implemented student lifecycle, document capture, editorial search, student view, and authentication
  • Integrated with the website
  • Built Linux server infrastructure
May 2013 - Aug 2013
4 months
Hamburg, Germany

Developer Content Management

Pharma

Storage system for incoming and outgoing invoices

Skills: Java, Alfresco Platform, Spring, Spring Security, Solr, REST services, BPMN, JavaScript, YUI, Dojo, Maven, MySQL, Active Directory, Git

  • Designed and implemented an invoice storage system based on Alfresco ECM and CMIS
  • Replicated content from ERP system
  • Implemented search
  • Enriched PDF documents with metadata from ERP system
  • Reconciled user master data with Active Directory
  • Authentication via Active Directory
Feb 2013 - Apr 2014
1 year 3 months
Hamburg, Germany

Lead Developer Content Management

Technical Service

Service workflow for technical inspection and testing services

Skills: Java, Alfresco Platform, Spring, Spring Security, Solr, REST services, Freemarker, JavaScript, YUI, Dojo, Groovy, Spock, Maven, MySQL, Git

  • Designed and implemented document management and workflow solution for technical inspection and testing services
  • Coordinated contractors and clients as a general contractor for technical services
  • Imported service orders via REST interface
  • Managed and monitored processes by contractors and clients
  • Processes for various document types such as briefings and reports
  • Multi-tenant solution with appropriate access control
Jan 2011 - Dec 2017
6 years
Hamburg, Germany

Lead Developer Content Management

Entertainment

Concert content management

Skills: Java SE/EE, Alfresco Platform, Spring, Spring Security, Lucene, Solr, Freemarker, Groovy, REST web services, JavaScript, YUI, Dojo, Groovy, Spock, Maven, Clojure, MySQL/PostgreSQL, Git, Docker

  • Designed and implemented a system for managing concert content (images, audio, video, documents) for various channels (websites, mobile)
  • Developed functionality for lifecycle, search, access control, and distribution
  • Implemented REST services (for UI and online shop)
  • On-premises Linux-based server infrastructure
Jan 2011 - Dec 2014
2 years
Hamburg, Germany

Grails Application Developer

Mail Order

Sidecar shopping cart

Skills: Groovy, Grails, Spring, jQuery, Spock, Angular, Selenium, Jenkins

  • Developed a shared shopping cart application with the Grails framework and Groovy
  • Features for group buyers, co-buyers, and employees
  • Integrated with surrounding shop system via REST and SOAP interfaces
  • Implemented lifecycle for carts and items (replicated), co-buyer master data, and cart merging
  • Implemented access control, fraud detection, and email notifications
Nov 2011 - Oct 2012
1 year
Hamburg, Germany

Lead Developer Content Management

Insurance

Help system for insurance agencies

Skills: Java, Alfresco Platform, Spring, Solr, CMIS/REST services, BPMN, Freemarker, JavaScript, YUI, Java Swing, Groovy, Spock, Maven, MySQL, Git

  • Designed and implemented a content management system for online help of insurance agencies using Alfresco ECM
  • Provided HTML-based content for about 2,500 agencies in a dedicated (Java desktop) application over VPN
  • Developed functionality for lifecycle, in-context editing, content aggregation, search, workflow management, and publishing
Jan 2005 - Jan 2018
12 years 1 month
Hamburg, Germany

Lead Developer Java

Mechanical Engineering

Quotation workflow system for heat exchangers

Skills: AWS, Java SE/EE, Spring, Struts, JSP, JMX, JSR-170 (JCR), Groovy, SOAP and REST web services, Bootstrap, Hibernate, MySQL, SQL Server, JBoss, Tomcat, Alfresco Platform, UML, Git

  • Designed and implemented a multi-tenant quotation workflow and marketing application
  • Integrated with ERP system
  • Tracked quotations
  • Managed documents stored in Alfresco ECM
  • Integrated automated price calculation system for binding quotes
  • Data synchronization with ERP systems
  • Set up Linux-based server infrastructure
Oct 2002 - Feb 2006
3 years 5 months
Hamburg, Germany

Lead Developer Infrastructure/Continuous Delivery

Finance

Website relaunch 2003 (before infrastructure was cool)

Skills: Linux, Java EE, RPC/SOAP web services, Orion Application Server, Contelligent Content Management System, Struts, Spring, Hibernate, Lucene, Jive Community, Oracle 9i, Eclipse 3, Ant, CVS, Perl

  • Re-implemented the website of an online bank/broker consisting of transactional, market data, member, and public areas
  • Built new Linux server and network infrastructure
  • Implemented sign-on in the public area
  • Components for community, search, member data, form center, and content management
  • Communication between components via RPC/SOAP web services
  • Responsible for design, implementation, and operation of about 25 Linux systems and networks
Jan 2001 - Feb 2006
5 years 2 months
Hamburg, Germany

Project Manager IT

Software

Skills: Linux, Java EE, Spring, Apple WebObjects, Perl, Shell

  • Designed, implemented, and managed various finance sector projects based on Linux, Java EE, and Apple WebObjects
Jan 1999 - Dec 2002
2 years
Hamburg, Germany

Developer

Software

Skills: Linux, Java EE, Apache Tomcat, Perl, Shell

  • Designed and implemented a journalistic image database and marketplace

Summary

  • Trust is the foundation of psychological safety and more important than technology.
  • Culture is the framework agreement - "... eats Strategy for Breakfast"
  • “We Shape Our Buildings; Thereafter They Shape Us”
  • One team, one goal
  • Change is the only Constant
  • Simplicity matters
  • Learning is a lifelong journey

Languages

German
Native
English
Advanced
French
Elementary

Education

University of Hamburg

Diploma · Physics · Hamburg, Germany

Certifications & licenses

AWS Certified Solutions Architect – Associate

AWS

Alfresco Certified Engineer

Alfresco

Certified Scrum Master

Sun Certified Enterprise Architect

Sun