The Technical Debt Gamble: A Case Study on Technical Debt in a Large-Scale Industrial Microservice Architecture

Abstract: Microservice architectures provide an intuitive promise of high maintainability and evolvability due to loose coupling. However, these quality attributes are notably vulnerable to technical debt (TD). Few studies address TD in microservice systems, particularly on a large scale. This research explores how TD manifests in a large-scale microservice-based industrial system. The research is based on a mixed-method case study of a project including over 100 microservices and serving over 15k locations. Results are collected via a quantitative method based static code analyzers combined with qualitative insights derived from a focus group discussion with the development team and a follow-up interview with the lead architect of the case study system. Results show that (1) simple static source code analysis can be an efficient and effective entry point for holistic TD discovery, (2) inadequate communication significantly contributes to TD, (3) misalignment between architectural and organizational structures can exacerbate TD accumulation, (4) microservices can rapidly cycle through TD accumulation and resolution, a phenomenon referred to as "microservice architecture technical debt gamble". Finally, we identify a set of fitting strategies for TD management in microservice architectures.