Microservices Logical Coupling : Measurement, Evolution, and Organizational Implications
Amoroso d'Aragona, Dario (2026)
Tampere University
2026
Tieto- ja sähkötekniikan tohtoriohjelma - Doctoral Programme in Computing and Electrical Engineering
Informaatioteknologian ja viestinnän tiedekunta - Faculty of Information Technology and Communication Sciences
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Väitöspäivä
2026-07-24
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-03-4709-3
https://urn.fi/URN:ISBN:978-952-03-4709-3
Tiivistelmä
Microservice architecture has emerged as a dominant paradigm for building largescale software systems, promising modularity, scalability, and independent evolution of services. A central premise of this paradigm is that architectural decomposition reduces inter-service dependencies and enables teams to develop and deploy services autonomously. Despite these expectations, empirical evidence on whether microservice systems actually achieve loose coupling in practice remains limited, particularly in open-source environments where development processes are highly decentralized.
This thesis investigates coupling phenomena in microservice-based open-source systems from both technical and organizational perspectives. The research follows a progressive investigative design structured around three stages: measurement, observation, and explanation.
First, the thesis introduces the Microservice Logical Coupling (MLC) metric, a repository-based approach for identifying evolutionary dependencies between microservices. By extending traditional logical coupling analysis from file-level artifacts to service-level entities, MLC enables the detection of cross-service evolutionary dependencies using version control data without requiring runtime instrumentation.
Second, the thesis conducts a large-scale empirical analysis to assess the prevalence and evolution of logical coupling across microservice-based open-source projects. The results show that logical coupling is a widespread phenomenon and tends to increase over time, suggesting that architectural boundaries alone do not guarantee independent service evolution.
Third, the study examines the socio-technical factors associated with coupling by analyzing developer contribution patterns and service ownership structures. The findings reveal a consistent association between cross-service developer activity and higher levels of logical coupling, indicating that organizational structures influence the emerqence of architectural dependencies.
Overall, this work contributes a replicable measurement approach, an empirically grounded empirical analysis of coupling in microservices, and a socio-technical perspective on microservice evolution. The results suggest that service independence is not solely an architectural property but a socio-technical outcome shaped by both system design and development practices.
This thesis investigates coupling phenomena in microservice-based open-source systems from both technical and organizational perspectives. The research follows a progressive investigative design structured around three stages: measurement, observation, and explanation.
First, the thesis introduces the Microservice Logical Coupling (MLC) metric, a repository-based approach for identifying evolutionary dependencies between microservices. By extending traditional logical coupling analysis from file-level artifacts to service-level entities, MLC enables the detection of cross-service evolutionary dependencies using version control data without requiring runtime instrumentation.
Second, the thesis conducts a large-scale empirical analysis to assess the prevalence and evolution of logical coupling across microservice-based open-source projects. The results show that logical coupling is a widespread phenomenon and tends to increase over time, suggesting that architectural boundaries alone do not guarantee independent service evolution.
Third, the study examines the socio-technical factors associated with coupling by analyzing developer contribution patterns and service ownership structures. The findings reveal a consistent association between cross-service developer activity and higher levels of logical coupling, indicating that organizational structures influence the emerqence of architectural dependencies.
Overall, this work contributes a replicable measurement approach, an empirically grounded empirical analysis of coupling in microservices, and a socio-technical perspective on microservice evolution. The results suggest that service independence is not solely an architectural property but a socio-technical outcome shaped by both system design and development practices.
Kokoelmat
- Väitöskirjat [5338]