PhD defense of Bruno STEVANT on May 23rd, 2022

Bruno Stevant defended his thesis on May 23, 2022 at 10:00 am in room Petri at IRISA. The title of the thesis is “Dynamic orchestration of microservices according to usage conditions.” The supervision of this thesis was provided by Jean-Louis Pazat, professor at INSA Rennes, and Alberto Blanc.


A participatory infrastructure aims to provide a hosting solution for services for a virtual community of users. Such a community has needs that are not fully met by data center hosting solutions. We therefore propose a new approach where community members host these services on their home devices. Such a participatory infrastructure raises issues related to the heterogeneity of the participating devices and networks, as well as to the variations in their computing and communication capabilities.

Through the study of existing solutions, the software architecture based on microservices has aroused our interest. It allows a more flexible placement of applications on the participating devices. The first part of our work consisted in finding a placement of the microservices on these devices that optimizes the response time of the applications. After defining a model of this response time, we used the PSO heuristic to find a solution close to the optimal one.

We tested this placement in real use conditions to evaluate the influence of network QoS variations on the application response time. This study showed that, under certain conditions, an adaptation of the placement could improve the measured performance. We have therefore added to our participatory infrastructure a mechanism capable of deciding whether an adaptation is necessary based on the measured response times, and to compute a placement adapted to the new conditions.