1. A method, comprising: receiving at least one of resource-level metrics and application-level metrics; estimating parameters of at least one application based on the at least one of the received resource-level and application-level metrics; and automatically and dynamically determining directives for scaling application deployment based on the estimated parameters; wherein at least one of the estimated parameters corresponds to an unobservable parameter of the at least one application and is estimated employing an estimation technique without accessing or modifying the at least one application; wherein the estimation technique continually adapts to dynamically changing system parameters during runtime; and wherein the receiving, estimating, and determining steps are performed by a computer system comprising a memory and at least one processor coupled to the memory.