Private cloud computing is an attempt to preserve many of the advantages of cloud computing, including lower hardware costs and dynamic scalability, while maintaining some level of control over physical computing resources. It addresses the privacy and security that have kept many businesses from investing in cloud computing. A cloud-like infrastructure might be built on a corporate network or software can be used to create greater security in an Internet-based cloud. A mix of public and private resources can also be used, and some believe the market will slowly shift towards public cloud computing.
Many organizations have been reluctant to embrace public cloud computing because it means entrusting internal data to third party who manages resources for many other users. Although users in a cloud can be separated from one another through software, the cloud as a whole relies upon shared resources, i.e., the data of many different users might be on the same physical hard disks. Private cloud computing has emerged as a response to the privacy and security concerns of many businesses; it seeks to provide many of the same benefits as ordinary cloud computing while preserving a greater level of isolation from the public.
There are many different approaches to private cloud computing, but they all involve a greater deal of security and control than the more traditional public offerings. In some cases, a cloud-like infrastructure might be built within the confines of a corporate network, with perhaps a few trusted business partners able to access this internal cloud. Outside vendors may build and maintain the cloud infrastructure, but the resources themselves are almost completely isolated from the outside world. For organizations such as hospitals that deal with sensitive or confidential data, an internal private cloud is often the preferred choice.
For clouds accessed over the Internet, technologies like Virtual Private Networking (VPN) can create a virtual layer of isolation while retaining all the benefits of a public cloud. Many public cloud providers have also established more private configurations for business customers. This can lessen the burden on an organization’s internal IT staff because the provider is responsible for setting up and maintaining the physical computing resources.
Some industry observers have predicted that private cloud computing is a temporary phenomenon that will be gradually replaced by a hybrid cloud. As its name implies, a hybrid cloud combines some aspects of both public and private clouds. A large enterprise might, for example, use a public cloud for non-sensitive data while maintaining its own internal IT services for more private matters. Special software that can move applications on demand between an external cloud and internal infrastructure might be used to help deal with spikes in demand or equipment outages. As more applications and services are created with cloud computing in mind, some believe the line between public and private cloud computing will one day be indistinguishable.