Effective provisioning of next generation distributed applications hosted on diverse middleware platforms incurs significant challenges due to the applications? growing complexity and quality of service (QoS) requirements. An effective provisioning of the middleware platform includes a composition and configuration of the middleware services thatmeets the applicationQoS requirements under expected workloads. Traditional techniques for middleware provisioning tend to use non-intuitive, low-level and technologyspecific approaches, which are tedious, error prone, nonreusable and not amenable to ease of QoS validation. Additionally, most often the configuration activities of the middleware platform tend to be decoupled from the QoS validation stages resulting in an iterative trial-and-error process between the two phases. This paper describes the design of a visual modeling language called POSAML (Patterns Oriented Software Architecture Modeling Language) and associated tools that provide an intuitive, higher level and unified framework for provisioning middleware platforms. POSAML provides visual modeling capabilities for middleware-independent provisioning while allowing automated middleware-specific QoS validation.