NIST definition of Hybrid Cloud: The cloud infrastructure is a composition of two or more distinct cloud infrastructures (private, community, or public) that remain unique entities, but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load balancing between clouds).
In a hybrid cloud, a company’s cloud deployment is split between public and private cloud infrastructure. Sensitive data remains within the private cloud where high security standards can be maintained. Operations that do not make use of sensitive data are carried out in the public cloud where infrastructure can scale to meet demands and costs are reduced.
Hybrid deployment architectures can be complex and challenging to create and maintain due to the potential disparity in cloud environments and the fact that management responsibilities are typically split between the private cloud provider organization and the public cloud provider.
How is Hybrid Cloud Used?
One of the example an organisation might use a hybrid cloud approach is by using their own on-premises dedicated servers for the hosting of particularly sensitive workloads or critical database, with their less critical workloads hosted with a public cloud provider.
Here organization is using 2 Cloud infrastructures, private cloud for hosting sensitive workloads or database, and public cloud for less critical workloads.