Consulting DevSecOps/SRE Engineer

Mavie is a holistic healthcare provider, offering a range of services from preventive care and rehabilitation to company health management and telehealth, all under the umbrella of the UNIQA Group.

I’m working with Mavie on establishing their Site Reliability Engineering practices from the ground up, bringing the teams up to speed in the use of DevSecOps and SRE practices with a focus on best-practice security aspects of cloud-based software development.

setting up an IaC platform for automated infrastructure deployment (initially Azure, then Google Cloud), establishing deployment and infrastructure framework for the common application infrastructure use-cases
ISO27001 compliace w.r.t Cloud Infrastructure
automating vulnerability detection and remediation
consolidating the infrastructure by migrating all applications away from various cloud-based vendors on the new Google Cloud based platform
setting up CI/CD pipelines with automated vulnerability scanning
setting up monitoring, alerting and on-call rotation
defining SLIs and SLOs, tunning them according to the needs of each business domain
defining deployment processes
securing access to critical parts of the infrastructure using fine-grained IAM policies, integrating Azure as IdP for GCP
etc.

Performance Engineer

Adaptive Financial Consulting

Banken und Finanzdienstleistungen

At Adaptive, I helped to benchmark the Aeron messaging platform on Amazon Web Services (AWS) and
another major cloud provider.

During the course of the project, I:

* built the infrastructure provisioning harness required to run the tests on two cloud providers
with different scenarios and configurations (instance types, network connectivity, storage,
etc.)
* built an automation for rendering results (latency graphs, experiment parameters, etc.)
* helped to run benchmarks, analyzing results and investigating performance issues
* built a tool for automatically provisioning, running and retrieving results

There is a press release from AWS on the topic and the performance testing results are publicly
available.

Tools used: AWS , Linux , Terraform , Bash , Performance Engineering , Python , Java

Tech Lead

Leap Energy (energy)

Energie, Wasser und Umwelt

After watching the drone footage of San Francisco in burning orange skies due to wildfires, with the
Blade Runner soundtrack playing on top of it, I decided to look for an engagement with a company
helping to do something to address climate change. This is how I learned about Leap Energy which
provides solutions for connecting distributed energy resources to wholesale energy markets in order
to make the electric grid more resilient.

In the role of Technical Lead I focused on projects in the following two areas:

* infrastructure modernization
* migration of the self-hosted customized VPN server to a cloud offering (vendor selection,
user migration)
* migration of the self-hosted Kafka cluster to Confluent Cloud (vendor selection, data
migration, integration with the monitoring system, service migration and coordinated rollout)

* migration of the self-hosted elasticsearch cluster to elastic cloud (vendor selection, data
migration, service migration, coordinated roll-out)
* microservice architecture modernization
* introduction of ADRs in order to document architecture decisions
* introduction of GRPC as a means for service-to-service communication (replacing direct
database access across services and an experimental service-to-service communication via
Kafka topics)
* development of a service protocol registry and distribution mechanism (based on protocol
buffers) to allow contract-first design and development of the various services

* introduction of Gradle with Kotlin support as a build tool as a replacement to maven and
porting multiple services
* introduction of jOOQ as a replacement to Hibernate for database access

Tools used: Kotlin , Java , Typescript, React, Go , Python , Bash , Gradle , Maven , GRPC , Kafka , SQL , elasticsearch ,
Terraform , AWS

Consultant

* review of the technical design of a single-node Akka application against the business
objectives
* support of the project team with regard to questions and issues arising during the project with
regard to the usage of Akka and Scala

Topics & tools: Actor Systems , Reactive design patterns , Akka , Scala

Consultant

Internet und Informationstechnologie

Architecture evaluation of an event-sourced system based on Apache Kafka and Kubernetes

Topics & tools: Event Sourcing , CQRS , Kafka , Kubernetes

Consultant

SwissBorg (cryptocurrency technology and services)

Banken und Finanzdienstleistungen

Troubleshooting performance issues with an Order Management System (based on Akka Cluster, Kafka and
Kubernetes) and setting up a large-scale load test for the system.

Topics & tools: Performance Engineering , Akka Cluster , Kafka , Kubernetes

Consultant

Paidy

The onboarding of a new strategic client on the Paidy platform brought with it stricter latency
requirements (in order to meet the agreed-upon Service Level Agreement). The backend application
built on top of Akka Cluster with cluster sharding did not deliver consistent latency in
redeployment and failover scenarios. I helped the engineering team find and understand the root
cause of the latency fluctuations and guided them throughout the process of implementing a solution.

Topics & tools: Performance Engineering , Akka Cluster , Akka Cluster Sharding , AWS ECS

Consultant

WireCard

Banken und Finanzdienstleistungen

Ongoing support of the engineering teams working on the next generation of the PSP (Payment Services
Provider) core platform:

* architecture reviews
* design and code reviews
* performance engineering workshops

Topics & tools: Reactive design principles , Actor systems , Event Sourcing , CQRS , Performance
Engineering , Akka , Akka Cluster

Consultant

Delivery Hero

Internet und Informationstechnologie

A core application based on Akka Cluster had ongoing memory issues, requiring to run virtual
machines with a lot of memory (64+ GB) as a workaround. I held a performance engineering workshop to
show the team how to use the adequate tooling for performance profiling and memory pressure
analysis. A key result of the workshop was a tenfold decrease of the JVM memory required to run the
project.

Topics & tools: Performance Engineering , Async Profiler , JVM memory management

Senior Software Engineer

MOIA, Payment Services (mobility)

Transport und Logistik

I joined the Payment Services team at MOIA to help with developing the second version of the payment
system based on Scala and Akka. The system needed to enable the payment of MOIA trips and needed to
integrate with multiple Payment Service Providers while providing strong consistency as well as
being highly available.

Tools used: Scala , Akka , Akka Cluster , Akka HTTP , SBT , DynamoDB , AWS Kinesis , PostgreSQL , AWS

Consultant

SwissBorg (cryptocurrency technology and services)

Banken und Finanzdienstleistungen

Development of a template project for deploying Akka Cluster projects with Kubernetes

Topics & tools: Kubernetes , Akka Cluster

Consultant

Metaco (cryptocurrency technology and services) Consulting

Banken und Finanzdienstleistungen

I supported the engineering team during the initial development of the SILO platform (based on Akka
Cluster and Scala) by:

* reviewing the system architecture and technical feature designs
* providing guidance and best practices with regard to the use of Akka Cluster, Scala and
Kubernetes
* developing the initial project scaffold and core application layer

Topics & tools: Reactive design principles , Actor systems , Akka , Akka Cluster , Scala , Kubernetes

Consultant

MOIA (mobility)

Consulting
Evaluation of the deployment of a split-brain resolution solution for Akka Cluster deployed with
Kubernetes on Amazon Web Services (AWS). At this time, there was no official support for Kubernetes
deployments of Akka and therefore I proceeded to analyze the deployment model with regard to
different edge-cases that could occur in a split-brain scenario.

Topics & tools: Distributed Systems , Akka Cluster , AWS

Consultant

Delivery Hero

Transport und Logistik

Architecture review and code review of an Akka Cluster based application

Topics & tools: Reactive design principles , Akka Cluster

Consultant

Consulting
* architecture of the new microservice-based software platform for an existing real-time
communication platform
* design and code reviews
* hands-on development of the core feature set of the platform (based on Akka, Scala and
Scala.js)

Topics & tools: Scala , Scala.js , Typescript , Akka , Kafka , SBT , Terraform , AWS

Senior Software Engineer

VCharge (acquired by OVO Energy) (energy)

Energie, Wasser und Umwelt

This engagement was a direct result of my work on deploying Akka on the Raspberry PI (see also the
initial article).

VCharge developed an embedded system and software solution to help address the issue of maintaining
the stability of the electric grid in the presence of increasing renewable generation.

During this engagement I supported VCharge in building a new version of the low-latency backend
service (based on Akka) responsible for aggregating telemetry as well as actuating the IoT devices
at the core of the VCharge Grid network.

Tools used: C , Scala , Python , Akka , elasticsearch , Kibana , Puppet , Bash , AWS

Author

Manning (publisher)

Authoring of the book Reactive Web Applications.

Read more about the story of writing the book.

Consultant

DIMOCO

Consulting
Testimonial

DIMOCO initially approached me in order to develop a prototype for an architecture evaluation with
Akka Cluster to help make a decision of which technology to use (the other contending technology was
VertX). I developed a software prototype deployed on multiple Raspberry PIs to demonstrate the
resilience and failover capability of Akka Cluster (unplugging a network cable while transactions
were being executed and showing that the processing continues and no transaction is failing makes
for a good demonstration).

Akka Cluster was subsequently selected as the technology to use for developing the new version of
DIMOCO's SMS delivery platform. I supported the engineering team in the early stages of the
development of the platform by:

* reviewing the architecture and the technical design
* regularly reviewing the code
* providing guidance and best practices with regard to the use of Akka and Akka Cluster

Topics & tools: Distributed systems , Reactive design principles , Akka Cluster , Kubernetes

Software Engineer

Nexxchange

Contracting
Testimonial

Nexxchange provides an all-in-one platform for managing Golf resorts and hotels.

I designed and implemented the online portal that aggregates the tee times of the multiple golf
clubs, making them searchable and bookable.

See also the Reactive Golf article series part 1, part 2 and part 3.

Tools used: Scala , Akka , Play Framework , Javascript , elasticsearch , MongoDB

Software Engineer

TalentHouse (digital marketing)

I joined the engineering team at TalentHouse in order to build the new version of the company site
using the Play Framework and Scala.

Tools used: Scala , Akka , Play Framework , Javascript , elasticsearch , RabbitMQ , PostgreSQL , Heroku

DevSecOps, Cloud Security, Site Reliability Engineering, Performance Optimization

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