Migrating Enterprise Legacy Source Code to Microservices: On Multitenancy, Statefulness, and Data Consistency

Microservice migration is a promising technique to incrementally modernize monolithic legacy enterprise applications and enable them to exploit the benefits of cloud-computing environments. This article elaborates on three challenges of microservice migration: multitenancy, statefulness, and data consistency. The authors show how to identify each of these challenges in legacy code and explain refactoring and architectural pattern-based migration techniques relevant to microservice architectures. They explain how multitenancy enables microservices to be utilized by different organizations with distinctive requirements, why statefulness affects both the availability and reliability of a microservice system, and why data consistency challenges are encountered when migrating legacy code that operates on a centralized data repository to microservices operating on decentralized data repositories. They also explain the interdependencies between multitenancy, statefulness, and data consistency.