An Empirical Investigation of Microservices-based Software Architectures from a Socio-Technical Perspective

Doctoral thesis, 2024

Background: As software systems grow, software organizations turn towards Microservices-based Software Architectures (MSAs) seeking modularity, service orientation, and cloud-based software delivery. Microservices are a way of structuring software systems into loosely coupled pieces that: 1) are developed and operated independently, 2) communicate and integrate with each other to compose a system, and 3) each piece has its individual business domain and resources. However, migrating towards microservices entails a lot of complexity. The change that a microservices migration predisposes has a socio-technical nature with changes in the technology, the organization, and software engineers.
Objective: Therefore, this thesis aims to draw a holistic framework describing the change that microservices introduce. Change that is introduced to the software, the software developing organizations, and importantly, the human practitioners developing the software. Specifically, the goal is to empirically demonstrate the journey towards MSAs, along with the decision-making, the technical artifacts change, and the practitioners’ roles, responsibilities, and skills in microservices.
Method: The methodologies of this thesis are based on inductive reasoning and use a combination of qualitative and quantitative methodologies. Grounded Theory and Grounded Theory-based analysis are used on interview data, textual data that engineers share in Q&A websites (i.e., StackOveflow), software repositories, and job-ads. In addition, a survey and automated analysis of StackOveflow data are also used.
Results: The main findings of this thesis are regarding the comprehensive perspective on microservices migrations that take place in multiple dimensions (business, technical, organizational), in multiple levels of abstraction (architecture and system), and in multiple modes of change (technical and systemic migrations). Specfically, 22 decisions and 53 solution outcomes are identified in detail. This work does not only approach migrations as a technical endeavor but also as an endeavor with a strong social and business aspect to it, covering the basic elements of socio-technical systems as defined in literature. Hence, the thesis presents taxonomies on the roles, responsibilities, and skills of microservices practitioners. Specifically, 3 roles of microservices practitioners are described in detail, along with 11 technical competences clusters, 5 families of responsibilities, 8 themes of soft-skills, and 11 themes of hard-skills.
Conclusion: Microservice migration projects entail an inherent complexity due to the different dimensions that the change takes place on, as well as the distributed nature of microservices. This work helps to decompose this complexity and carry a detailed understanding of microservices migrations to future attempts. In addition, this thesis paves the way for preparing engineers to work with MSAs.