From Monolith to Microservices: Lessons Learned on an Industrial Migration to a Web Oriented Architecture

MGDIS SA is a software editing company that underwent a major strategic and technical change during the past three years, investing 17 300 man. Days rewriting its core business software from monolithic architecture to a Web Oriented Architecture using microservices. The paper presents technical lessons learned during and from this migration by addressing three crucial questions for a successful context-adapted migration towards a Web Oriented Architecture: how to determine (i) the most suitable granularity of micro-services, (ii) the most appropriate deployment and (iii) the most efficient orchestration?