VMware's vCloud initiative has attracted roughly 8,500 cloud service providers (CSPs) and datacenter providers, the virtualization company indicated at VMworld 2012. A lot of those CSPs are small, localized, regional service providers pushing into the cloud market, according to VMware (NYSE: VMW) Chief Marketing Officer Rick Jackson.

vCloud allows partners and customers to license VMware on a subscription model. Of those CSPs, roughly 120 are fully certified -- meaning they are taking their vCloud services live, with VMware's stamp of approval. Jackson mentioned that a healthy number of MSPs are embracing VMware's vCloud Suite as a cloud foundation, and vCloud Director as a front end.

VMware is evangelizing a push beyond virtualization to software-defined data centers. At the same time, VMware has been working with Ingram Micro and other distributors worldwide to promote the service provider licensing model.

Back in July 2011, VMware estimated that it had more than 5,200 service provider partners. That figure now stands at 8,500 -- apparently up around 3,200 service providers in the past year.

Some critics wonder if VMware can continue to grow rapidly amid potential competition from Windows Server 2012 (and an improved Hyper-V), plus emerging open source cloud alternatives like OpenStack, which appear more closely aligned with KVM (kernel-based virtual machine). VMware will need to show critics that the service provider licensing model remains a long-term growth engine.