1. A method of dynamically resizing a virtual machine container, the method comprising: determining a possible size of the virtual machine container within a resource-on-demand environment in accordance with a service level agreement; determining a corrected optimal utilization based on a desired performance for a multi-tiered application and transaction mix information that describes a mix of transactions that result from executing the multi-tiered application, the determining of the corrected optimal utilization further comprising: determining a correction term based on a difference between the desired performance and a measured performance; and determining the corrected optimal utilization based on the correction term and an uncorrected optimal utilization, wherein the uncorrected optimal utilization is based at least on service time of transactions, the mix of transactions, and fixed delays; enabling automatic modification of an amount of a physical resource a virtual machine container is entitled to execute a particular application component associated with the multi-tiered application, wherein the amount of the physical resource is determined based at least in part on a ratio of physical resource consumption and physical resource entitlement, wherein the amount is automatically modified based on the corrected optimal utilization and the possible size of the virtual machine container; and using the corrected optimal utilization for all of the application components associated with the multi-tiered application.