Cloud computing has been a boon to conserving resources by providing a farm of servers that are concurrently used by multiple users. Cloud computing precludes the requirement for setting up per-user servers. In a recent InformationWeek survey of business technology professionals, most have indicated a preference for cloud computing for storage, archiving, and disaster recovery, for business applications, servers, raw computing power, dedicated data center space, databases, and specialized IT services such as security, management and compliance.

Cloud computing may be public or private. In public cloud computing resources are shared over the Internet on a fine-grained self-service basis such as Amazon EC2. Private cloud computing is the equivalent of public cloud computing on a private network. Resource efficiencies associated with public cloud computing outweigh those associated with private cloud computing due to the limited scope of private cloud computing as it is isolated to an enterprise. Private cloud computing does provide the benefits of enterprise level security and reliability. Most applications are designed for the tightly coupled enterprise environment and switching costs are involved to migrate them to loosely coupled cloud environments.

Hybrid cloud computing has emerged to benefit from both the "private cloud" and "public cloud" architectures by spanning enterprise data centers and public clouds (such as the Amazon EC2). Combining virtual and physical collocated assets, such as routers and servers, is the preferred implementation by most enterprises. The main advantage of cloud computing is scalability. Most enterprises have organization-level resources that may at times be required to be extended to a public cloud. If an application requires more than anticipated resources, more resources may be allocated to the application on a public cloud. Hybrid clouds also include allocating resources to a different public cloud if the servers at one of the public clouds overloads.

Based on the concept of multiple public clouds IBM has introduced a hybrid cloud in alliance with Juniper Networks in which users are allocated to a different cloud if a cloud overloads. Juniper shall be providing hybrid cloud computing to IBM's 9 worldwide computing labs. IBM Cloud Labs provides the world's largest network of cloud computing labs extending from the Silicon Valley to Tokyo, Japan. In collaboration with Juniper, IBM offers drag-and-drop cloud management with its Cloud Management Console to extend computing resources between private and public clouds. The console shows virtual machines as small color-coded (to indicate if they are being used) boxes that may be selected to allocate resources. Juniper provides the remote management of clouds over Multiprotocol Label Switching (MPLS) networks. IBM's hybrid cloud computing is backed with other computing services; Service Management Center for Cloud Computing, which clients may use to build and deliver cloud services; IBM Rational AppScan 7.8 for securing web services published into a cloud; and IBM Design and Implementation for Cloud Test Environments for testing clouds within client environments.

Hybrid cloud computing in which enterprises extend their resources to public clouds is the trend of the future. In addition to providing reliability and scalability of public clouds, hybrid cloud computing has the appeal of providing the most suitable environment for applications. Some applications, such as databases, run better on a dedicated server than on a shared server. And other applications run better on a cloud as they are able to avail of the extensibility of the cloud to scale as required.

"Hybrid" implies "public" and "private" clouds, and providing multiple public clouds does not diminish the demand for private clouds. WebSphere Cloudburst appliance provides the ability to create and deploy WebSphere environments to private clouds. Some of the other private cloud products include 3Tera's AppLogic, ParaScale's Virtual Storage Network (VSN), and Cassatt's Collage 4.0.

Hybrid cloud computing is the future direction of cloud computing and increasingly hybrid cloud products are being offered. The Citrix Cloud Center C3 technologies provide a hybrid cloud. The Elastra Enterprise Cloud Server has been named one of the "100 Coolest Cloud Computing products" and provides federated hybrid cloud management. For a demo of Hybrid clouds refer the Elastra Hybrid Cloud Administration demo. As recently as a few months ago Microsoft emphasized the hybrid cloud at TechEd. OpenNebula recently released a Datacloud adaptor for Hybrid clouds. IBM recently acquired Cast Iron Systems to provide support for hybrid clouds. Hybrid cloud computing is the future trend in enterprises as noted by Lucas Searle, head of virtualization at Microsoft UK.