What is a private cloud?

According to the National Institute of Standards and Technology (NIST), private cloud means: “The cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on premise or off premise.” Private clouds are placed behind the firewall of an organization and are often used as internal tools or secure infrastructures on which to store data and perform internal operations. Private clouds are chosen as a cloud deployment model by organizations that want to keep their data secure and safe inside their own private infrastructure. Examples of a private cloud might include research infrastructure for a genetic informatics company or a business that uses internal cloud infrastructure to do large-scale analytics on commercial data.

A concept related to the private cloud called a Private Computer Utility was first introduced over forty years ago in Douglas Parkhill’s book, "The Challenge of the Computer Utility". Terms such as ‘Cloud’, ‘Private Cloud’, and ‘Public Cloud’ were introduced recently, but they refer to concepts that have been around for more than forty years.

Sometimes vendors will incorrectly use the terms ‘Private Cloud’ or ‘Internal Cloud’ to describe offerings that provide some cloud computing benefits (and avoid certain cloud pitfalls) on a private network. These pseudo-clouds often employ technologies such as virtualization automation. However, users still have to build and manage these solutions.

There are three other distinct deployment models besides private clouds. They include community clouds, public clouds, and hybrid clouds. You would think that community clouds are similar to public clouds, but they are actually considered by some to be a subset of the private cloud designation. This is because community clouds are still not open to the “public”. Instead, a community cloud is like a private cloud for more than one organization. Google’s “Gov Cloud” is an example of a community cloud.

A hybrid cloud is just what it sounds like: a mix between a private and public cloud. It includes multiple providers that can be both internal and external. Some computing can be done securely in the private infrastructure while the public facing services can be deployed on the public infrastructure. Finally, you have fully public clouds like Amazon EC2 and Google App Engine. These deployments are provided through internet systems that are potentially available to any member of the public.

About the Cloud

The Cloud uses internet connections to link computing resources together into one big pool of computing resources that the customers don’t need to manage. Cloud computing infrastructure is made up of both remote and local server arrays that share and balance storage or processing power much like an electricity grid shares energy. This allows organizations to provide a much more efficient software deployment architecture or infrastructure service. Organizations can then pass on the savings to their customers through the avoidance of overhead costs (i.e. buying servers) and the as-needed payment model for services.

A proprietary network that provides hosted services to a limited number of people behind a firewall. The network uses cloud computing technologies, such as virtualization. A private cloud is managed by the company it serves. Private clouds appeal to companies that want more control over their data than they can get by using a third party hosted service.