Towards Resource and Contract Heterogeneity Aware Rescaling for Cloud-Hosted Applications

Abstract

Cloud infrastructure providers are offering consumers a wide range of resource and contract options to choose from, yet most elasticity management solutions are incapable of leveraging this to optimize the cost and performance of cloudhosted applications. To address this problem, in this paper, we propose a novel resource scaling approach that exploits both resource and contract heterogeneity to achieve optimal resource allocations and better cost control. We model resource allocation as an Unbounded Knapsack Problem, and resource scaling as an one-step ahead resource allocation problem. Based on this, we present two scaling strategies, namely delta scale optimization and full scale optimization. Delta scale optimization supports the traditional notion of scaling resources horizontally, i.e., it computes an optimal allocation (or deallocation) of resources to increase (or decrease) the total compute capacity based on the current allocation and the forecast application workload. Full scale optimization, on the other hand, supports the notion of cost-optimal resource rescaling, i.e., the simultaneous allocation and deallocation of resources to meet the forecast workload irrespective of the decision to increase, decrease or maintain capacity. Both strategies provide users greater flexibility in managing trade offs between cost and performance. We motivate our research work by using a realistic and non-trivial scenario of resource scaling for a cloud-hosted IoT platform and use simple use cases to illustrate the benefit of our proposed approach.