1. A method of processing and controlling a virtual server that is performed by a management server for a hypervisor that can operate the virtual server, wherein the hypervisor operates on one physical server, the virtual server operates in accordance with a file image on one data store, and the management server: when instructed to execute a task that is configured by a series of steps for a predetermined execution place, gives an instruction for changing the execution place of the steps to a temporary execution place and executing the task and, after the execution at the temporary execution place, causes the virtual server to transit from the temporary execution place to the predetermined execution place, and gives an instruction for continuously executing the task at the predetermined execution place, wherein the execution place is any of a place of one hypervisor, a place of one data store, and a place of a combination of one hypervisor and one data store, when there is no restriction on the execution place of the steps and load or a simultaneous execution number of the hypervisor configuring the predetermined execution place is detected to exceed a predetermined threshold, changes the execution place of the steps to the temporary execution place and instructs the hypervisor configuring the temporary execution place to execute the steps, when there is a restriction on the execution place of the steps and load or a simultaneous execution number of the hypervisor configuring the predetermined execution place is detected not to exceed the predetermined threshold, instructs the hypervisor configuring the predetermined execution place to execute the steps.