Dynamic Horizontal and Vertical Scaling for Multi-tier Web Applications

The adaptive resource provisioning of cloud-hosted applications is enabled to provide a better quality of services to the users of applications. Most of the cloud-hosted applications follow the multi-tier architecture model. However, it is challenging to adaptively provision the resources of multi-tier applications. In this paper, we propose an auto-scaling method to dynamically scale resources for multi-tier web applications. The proposed method exploits the horizontal scaling at the web server tier and vertical scaling at the database tier dynamically to maintain response time guarantees. We evaluated our proposed method on Amazon Web Services using a real web application. The extensive experimental results show the effectiveness of our proposed method in terms of performance and cost when compared with current practices of static and dynamic resources over-provisioning methods.