<P> Another example of hybrid cloud is one where IT organizations use public cloud computing resources to meet temporary capacity needs that cannot be met by the private cloud . This capability enables hybrid clouds to employ cloud bursting for scaling across clouds . Cloud bursting is an application deployment model in which an application runs in a private cloud or data center and "bursts" to a public cloud when the demand for computing capacity increases . A primary advantage of cloud bursting and a hybrid cloud model is that an organization pays for extra compute resources only when they are needed . Cloud bursting enables data centers to create an in - house IT infrastructure that supports average workloads, and use cloud resources from public or private clouds, during spikes in processing demands . The specialized model of hybrid cloud, which is built atop heterogeneous hardware, is called "Cross-platform Hybrid Cloud". A cross-platform hybrid cloud is usually powered by different CPU architectures, for example, x86 - 64 and ARM, underneath . Users can transparently deploy and scale applications without knowledge of the cloud's hardware diversity . This kind of cloud emerges from the raise of ARM - based system - on - chip for server - class computing . </P> <P> Community cloud shares infrastructure between several organizations from a specific community with common concerns (security, compliance, jurisdiction, etc .), whether managed internally or by a third - party, and either hosted internally or externally . The costs are spread over fewer users than a public cloud (but more than a private cloud), so only some of the cost savings potential of cloud computing are realized . </P> <P> A cloud computing platform can be assembled from a distributed set of machines in different locations, connected to a single network or hub service . It is possible to distinguish between two types of distributed clouds: public - resource computing and volunteer cloud . </P> <Ul> <Li> Public - resource computing--This type of distributed cloud results from an expansive definition of cloud computing, because they are more akin to distributed computing than cloud computing . Nonetheless, it is considered a sub-class of cloud computing, and some examples include distributed computing platforms such as BOINC and Folding@Home . </Li> <Li> Volunteer cloud--Volunteer cloud computing is characterized as the intersection of public - resource computing and cloud computing, where a cloud computing infrastructure is built using volunteered resources . Many challenges arise from this type of infrastructure, because of the volatility of the resources used to built it and the dynamic environment it operates in . It can also be called peer - to - peer clouds, or ad - hoc clouds . An interesting effort in such direction is Cloud@Home, it aims to implement a cloud computing infrastructure using volunteered resources providing a business - model to incentivize contributions through financial restitution . </Li> </Ul>

Which technology forms the foundation for cloud computing