Automated provisioning of virtual machines for a virtual machine buffer pool and production pool

An automated provisioning system provisions computing resources for shared services in a resource-on-demand system. A number of virtual machines needed for a virtual machine production pool for a period of time to satisfy the computing demand for the shared services is determined from a policy. Also, a number of unassigned virtual machines needed for a virtual machine buffer pool is determined from the policy. Servers and virtual machines are automatically provisioned for the virtual machine production pool and the virtual machine buffer pool based on the determined number of virtual machines needed for the virtual machine production pool, the determined number of unassigned virtual machines needed for the virtual machine buffer pool, and a changing computing demand of the shared services during the period of time.