Senior Developer | Architect
2020 - 2022City of Amsterdam- Automated self-service provisioning of (cloud-) storage, Spark clusters, Kafka, and much more.
- Maintained Kubernetes clusters through Rancher, as AKS in Azure, and manually.
- Designed and deployed OIDC-based identity and access management (IAM) using 389ds (LDAP) and Keycloak. Integrated a large number of applications and services with this IAM.
Technologies: Azure, GitLab CI/CD, Kubernetes, Azure Kubernetes Service (AKS), Spark, Apache Airflow, Python 3, Data-level Security, Aiohttp, Asynchronous Programming, Flask, REST, Rancher, Databricks, MinIO, LDAP, 389 Directory Server, Keycloak, OpenID Connect (OIDC), OAuth 2, REST APIs, Public-key Cryptography, Linux, APIs, SQL, Python, Unix, X.509, Architecture, Identity & Access Management (IAM)Senior DevOps | Architect
2017 - 2020City of Amsterdam- Built advanced, asynchronous, and high-performance RESTful APIs for publication of open data.
- Designed and implemented federated identity and access management and single sign-on for an infrastructure of 20+ microservices, with seven identity providers crossing organizational boundaries using Keycloak.
- Selected and provisioned API management tools for access management, versioning, and load balancing.
- Built a web service plus Python command-line interface for pseudonymization of personal data to allow multiple organizations to exchange and combine datasets without compromising anonymity.
Technologies: Asynchronous Programming, Ansible, OpenStack, OpenID Connect (OIDC), GIS, Kubernetes, Docker, REST APIs, REST, Public-key Cryptography, Linux, APIs, SQL, Keycloak, Data-level Security, Python 3, Python, Unix, X.509, LDAP, Architecture, Identity & Access Management (IAM)Co-founder and CTO
2013 - 2017Lucipher.net- Co-founded the company.
- Invented and implemented a new method for public key exchange.
- Invented and implemented a provably and verifiably secure method for exchanging data within dynamic user groups wherein all users can invite new users. The method is to be used in group chat applications and electronic medical records, and also in military, police, and intelligence communities.
- Successfully applied for a Dutch high-tech stimulation grant.
- Followed the course “Cryptography I” at Stanford University and obtained a certificate of achievement.
- Experimented with the latest homomorphic encryption schemes.
Technologies: iOS, Android, Encryption, OpenPGP, REST APIs, REST, Public-key Cryptography, Linux, APIs, SQL, Data-level Security, Python 3, Python, Unix, X.509, Architecture, Identity & Access Management (IAM)Interim CTO
2016 - 2016MADS- Selected and recruited seven new employees.
- Asserted business continuity by analyzing/debugging their systems and implementing basic service/asset management routines.
- Analyzed software and services, documented the architecture, and planned the most urgently needed upgrades and refactoring.
- Estimated staffing needs for the next two years, and defended this estimation to the board.
Technologies: REST APIs, REST, Linux, APIs, Unix, Architecture, Identity & Access Management (IAM)Consultant
2015 - 2015ASTRON- Designed a high-performance compute cluster that meets the computational requirements of the LOFAR International Radio Telescope.
- Wrote the technical specifications document of a European public Request for Offer.
Technologies: High-performance Computing, Linux, Unix, PhysicsSenior Developer
2014 - 2015Multinational Bank- Implemented continuous delivery (zero touch deployment) of Hortonworks Hadoop on a set of DTAP big data clusters, as part of the bank’s data lake strategy.
Technologies: Hadoop, Python, Java, Nolio Release Automation, Jenkins, REST APIs, REST, Public-key Cryptography, Linux, APIs, Unix, Identity & Access Management (IAM)System Architect/DevOps
2013 - 2013Vancis- Commissioned a 32-node RHEL cluster with PXE, kickstart, Xen, and Puppet.
- Deployed Hortonworks’ HDP on a virtualized, multi-tenant compute cluster.
- Helped design and implement virtualized network topology for multi-tenant compute cluster.
Technologies: Puppet, Hortonworks Data Platform (HDP), LDAP, PXE, Xen, Hadoop, REST APIs, REST, Public-key Cryptography, Linux, APIs, Unix, Architecture, Identity & Access Management (IAM)Senior Advisor
2006 - 2013SARA- Developed CoPub, a literature-based keyword enrichment tool for microarray data analysis.
- Invented, oversaw the development of, and managed BeeHub, a peta-scale data storage and exchange for academic research.
- Invented, oversaw the development of, and managed the GridAppsPortal, a web portal for efficiently running common large scale computations (e.g., BLAST) on the LHC Compute Grid with tens of thousands of compute nodes and petabytes of storage.
- Advised and co-developed EsiBayes, a web portal for performing large-scale inverse modeling, machine learning, and parameter optimization on the Dutch Life Science Grid (LSG) and National Compute Cluster (LISA).
- Ported a computationally intensive tomographic reconstruction algorithm from CPUs to GPUs (NVidia Tesla cards) with NVidia's CUDA and CuFFT toolkits.
Technologies: Storage, Grid Computing, Machine Learning, Big Data, High-performance Computing, REST APIs, REST, Public-key Cryptography, Linux, APIs, SQL, Python 3, Python, Unix, X.509, Sequence Alignment, Bayesian Statistics, LDAP, Intel MKL, LAPACK, Sun Grid Engine, GPGPU, GPFS, Identity & Access Management (IAM), PhysicsOwner
1997 - 2006Q-factor- Built some of the first eCommerce websites for clients including a large Dutch bookstore chain.
- Built an online, Flash-based game for the University of Amsterdam and a television broadcasting company (VPRO) that allowed academic economists to observe and experiment with human behavior in tit-for-tat games.
- Built many high-performance computing applications for parallel compute clusters for clients including the University of Munich, Germany.
- Conducted big data analysis for the Netherlands’ largest video rental store chain (Videoland) for targeted marketing purposes.
- Built a system for administration and fiscal dispatching of car mileage logs for the city of Amsterdam in the Netherlands.
Technologies: Web Programming, Vectorization, eCommerce, REST APIs, REST, Public-key Cryptography, Linux, APIs, SQL, Unix, X.509