On optimizing resource allocation and application placement costs in cloud systems

Resource utilization problem has been widely studied for cloud systems where a number of virtualized resources are shared among applications hosted as services. Resource utilization optimization can be confronted at two levels: Allocating resources to virtual machines(VM) across physical machines or assigning applications to virtual machines present in the host. With the improving capabilities on virtualization technologies, realizing resource allocation at both levels is becoming more viable using VM reconfiguration and live-migration of applications. In this paper we investigate applying resource allocation optimization at these two levels and the emerging trade-off in deciding the appropriate technique to be used. We first analyze the effect of gradually increasing the amount of resources assigned to a virtual machine using VM reconfiguration and compare our results with fully assigning host's resources without reconfiguration. Later, we investigate the amount of utilization revenue when application live-migration is used for applications having smaller/larger performance needs. Finally, we compare the host utilization for different amounts of cost rates between live-migration and reconfiguration. Consequently our analysis results identify the cost rate and application granularity levels where it is optimal to apply live-migration or VM reconfiguration.