Robust Performance Control for Web Applications in the Cloud

With the success of Cloud computing, more and more websites have been moved to cloud platforms. The elasticity and high availability of cloud solutions are attractive features for hosting web applications. In particular, the elasticity is supported through trigger-based provisioning systems that dynamically add/release resources when certain conditions are met. However, when dealing with websites, this operation becomes more problematic, as the workload demand fluctuates following an irregular pattern. An excessive reactiveness turns these systems into imprecise and wasteful in terms of SLA fulfillment and resource consumption. In this paper, we propose three different provisioning techniques that expose the limitations of traditional systems, and overcomes their drawbacks without overly increasing complexity. Our experiments conducted on both public and private infrastructures show significant reductions in SLA violations while offering performance stability.