Container overhead in microservice systems

Abstract: Containers have been gaining popularity in recent years due to their ability to provide higher flexibility, higher reliability and dynamic scalability to enterprise software systems. In order to fully utilize containers, software developers aim to build their software using microservice architecture, meaning that instead of working on a single large codebase for the whole project, the software is split into smaller units. These microservices can be deployed in their own container instead of the traditional virtual machine setup where a server has to configured with all necessary dependencies. Moving away from the monolithic software architecture to containerized microservices is bound to bring performance penalties due to increased network calls between services and container overhead. The integration must therefor be carefully planned in order to fully utilize the container setup while minimizing the overhead. The purpose of this thesis project was to measure how much overhead can be expected due to containers in an enterprise environment. By using a combination of virtual machines and Docker containers, a microservice system was deployed with four different deployment strategies and the system’s performance was measured by analyzing request response times under various loads. The services were made to run on a single server and on multiple servers, with and without Docker. The performance measurements showed that the system performed worse in every case when Docker was used. Furthermore, the results showed that Docker can have significant negative impact on performance when there is a heavy load on the system.