John Flionis Email & Phone Number

Lausanne Metropolitan Area

London, England, United Kingdom

Technical responsibilities & achievements:✅ Platform architecting & refactoring of Terraform code to enable scalability over multi-cluster & multi-region for infrastructure components of high-scale ML-based API services, achieving the serving of a record-amount of customer requests✅ Reliable autoscaling tuning, conducting performance testing & comparison of system throughput, robustness & cost efficiency assessing quality of service before releasing breaking architectural changes✅ Conducting Terraform state migrations of existing infrastructure components on live environments to refactored Terraform modules with zero downtime from a customer perspective✅ Development of new & extension of existing infrastructure provisioning & configuration scripts (Terraform, ArgoCD), towards automating repetitive manual tasks prone to human error✅ Led cross-region migration transfers of ML training big data (S3, FSx)✅ Became member of on-call rotation, applying incident analysis, investigation & response on high-scale traffic bugs - multiple production environments with >1000 nodes per cluster, and >16M videos of 20 sec duration classified by AI/ML models per 24h✅ Contribution of improvements in alerting & monitoring practices that provided enhanced insights to system observability, as well as reduced noise in alerting mechanisms

Thessaloniki, Central Macedonia, Greece

Technical responsibilities & achievements:✅ Refactored naive CI/CD pipeline applying advanced concepts, in a template-driven & configurable manner for multiple microservices reusability, leading into minimal initial deployment effort, faster & more reliable pipeline runs✅ Improved software quality assurance via introduction of diverse forms of software testing and introduction of Code Quality & Code Security scanning tool into CI/CD pipeline, leading into less code defects & reduced code vulnerabilities✅ Cloud infrastructure provisioning, maintenance, management, and scaling on AWS, leading to improved infrastructure durability, agility and scalability✅ Cloud infrastructure cost-optimization in collaboration with cost-opt specialists, leading into an initial 20% cost reduction (work in-progress)✅ Applied incident analysis via logs & metrics investigation, leading into rapid bug detection & performance-optimization of production-grade services✅ Improved security posture of infrastructure in the process of ISO 27001 & ISO 22301 compliance, leading into ISO 22301 certification by the end of April and projected to be certified with ISO 27001 by end of 2023Cultural impact:✅ Increased collaboration between development & operations teams, leading into better understanding and improved performance✅ Cultural change through introduction of stable distributed microservices architecture & shortening tech product release cycles✅ Improved security awareness of co-workers through guidance into applying security practices in daily activities & safer code development

Thessaloniki, Central Macedonia, Greece

Technical responsibilities & achievements:✅ Cloud infrastructure provisioning and services migration from local deployment to AWS EKS, leading into improved infrastructure durability, agility and scalability✅ Introduced the concept of IaC & GitOps, enabling automated provisioning and management of kubernetes resources through code, leading into increased reliability and easier collaboration✅ Naive CI/CD pipeline design and adoption, leading into automatic deployment of new code releases✅ Deployed & maintained monitoring & logging stack (PLG), leading into improved observability of microservices infrastructure

Thessaloniki, Central Macedonia, Greece

Contribution in research projects: ▪️ AI/ML algorithms (Autoencoders, GANs, CNNs, BERT, ViT, etc.) application for Intrusion Detection Systems on 5G Networks ▪️ ARES'22 publication: Image-based Neural Network Models for Malware Traffic Classification using PCAP to Picture Conversion▪️ Development & deployment of Blockchain-based platform for health data application on Kubernetes