Abstract: Hybrid cloud computing has be a promising solution for Software-as-a-Service (SaaS) providers to effectively handle the dynamic user requests. The SaaS providers can extend their services into the public clouds seamlessly so that the dynamic user request workload to a SaaS can be elegantly processed with both the local servers and the rented computing capacity in the public cloud. However, although it is suggested that a hybrid cloud may save cost compared with building a powerful private cloud, considerable renting cost and communication cost. We design a service provisioning model to manage the on-spot and on-demand requirements of users. PaaS satisfy on-spot by providing space from public cloud to SaaS. This proposed method is done with online dynamic provision algorithm which calculates the number of users request for service. Depending upon this calculation the SaaS will purchase the virtual machine from PaaS and the transactions are done to pay for what is actually used.
Keywords: Platform-as-a-service (PaaS), Software-as-a-service (SaaS), Virtual machine.