Unequal-interval based loosely coupled control method for auto-scaling heterogeneous cloud resources for web applications

Abstract

Most existing quality of service (QoS) control algorithms of Web applications take into account Web Server or database connections which can be released immediately. However, many applications are deployed on virtual machines (VMs) or even Spot VMs elastically rented from public Clouds. To save costs, interval-priced VMs are not released until the ends of rented intervals. Such delays of control effects make existing methods rent or release excess VMs leading to overcontrol. Fluctuated prices make Spot VMs unreliable due to unexpected termination which makes fault-tolerant strategies crucial. In this article, an unequal-interval-based loosely coupled control method is proposed to improve the..