SLA-based Resource Provisioning for Management of Cloud-based Software-as-a-Service Applications

The Cloud computing Software-as-a-Service (SaaS) model has changed the sales model for software providers. The SaaS model transforms the traditional license based model to a subscription model, which allows customers to access applications over the Internet without software and hardware upfront costs and provides reduced maintenance costs. However, the key for sales is still customer satisfaction which is at the heart of the selling process. To guarantee Quality of Service (QoS) for customer satisfaction therefore, the Service Level Agreement (SLA) is implemented between customers and SaaS providers, where the main objectives are profit maximization and increased market share. To achieve these objectives, there are several challenges due to the dynamic nature of the Cloud environment. Firstly, the SaaS provider utilizes shared infrastructure and various types of request loads which can lead to unpredictability in performance and availability of resources. Secondly, there is a possibility that existing customers may make changes in requirements, which can lead to resource reallocation. As such, resource allocation may cause SLA violations which could reduce the SaaS providers’ profit margin and reputation, meaning a possible loss of existing customers and potential new customers. Thirdly, SaaS providers need to attract customers with special needs and consider market competition from other providers in order to increase profit and market share. To overcome the above challenges, most proposed solutions are focused on the resource management with the aim of minimizing cost without sufficiently consideration of customer’ needs. Therefore, to address these challenges, this thesis proposes algorithms and techniques for optimal provisioning of Cloud resources with the aim of maximizing profit and customer base by handling the dynamism associated with SLAs and heterogeneous resources. The key contributions of the thesis are:  A comprehensive survey of how SLAs are created, managed and used with case examples drawn from both academy and industry with a major emphasis on the SLAbased resource management systems.  The admission control and scheduling algorithms assist in identifying which request is more acceptable based on profitability, reducing the probability of SLA violations given the heterogeneous nature of Cloud resources.  The customer requirements driven resource provisioning algorithms can help in adapting to changes in the requirements. The proposed algorithms provide personalized attention to the customer and are also able to understand specific customer needs.  A new negotiation framework to enlarge a SaaS provider’s customer base that considers dynamism in the Cloud environment with time and market factors to make the best possible decisions for negotiation.  A prototype of the customer requirements driven SLA-based resource management system to prove the usefulness of our proposed strategies using the latest technologies.