There are many successful case studies of SOA adoption, mainly in commercial enterprises. Part of what Gartner terms the "period of enlightenment" related to hype cycles for emerging technology is the move from SOA as simply a set of technologies to service-orientation as a mind-set for architecting, implementing, and deploying services that add value to an organization. Regardless of this positive perception change, there are still two concerns from a maintenance and evolution perspective: (1) deployed service-oriented systems will have to be maintained and evolved and (2) legacy systems will continue to use service-orientation to make their legacy functionality available to other systems and applications. Cloud Computing is emerging as a model for system development and deployment, in which systems use resources from—or are hosted, run, and managed in—large server farms and data centers and are provided as a service. The lack of control over these external resources creates additional challenges for systems migrating to these environments. Resources in cloud environments are typically deployed as services and accessed via a service interface, which creates a natural connection between SOA and cloud computing.