In the early part of 2013, EMC announced a new storage virtualization product called ViPR that delivers a software interface to block, object and HDFS storage services layered on heterogeneous storage. As part of that announcement there was an architectural discussion regarding how ViPR would be providing these services to applications that entails breaking out the design into two components: the control plane and the data plane.
The control plane provides common interfaces for provisioning, policy & management while the data plane provides interfaces for data access from applications. In separating out these two layers, EMC creates an architecture that is agile and enables new services to be added over time without impacting production services. Since ViPR is focused on storage, it will, unfortunately, never be expanded to encompass an entire cloud management stack. However, the architecture is interesting and aspects of it lend itself to building a best-of-breed cloud management platform.