I am continuing my series of articles where I share my interpretation of the National Institute of Standards and Technology’s special publication 800-145. This week the focus is on the four different deployment models of cloud computing according to the NIST’s definition:
Private cloud. The cloud infrastructure is provisioned for exclusive use by a single organization comprising multiple consumers (e.g., business units). It may be owned, managed, and operated by the organization, a third party, or some combination of them, and it may exist on or off premises.
Community cloud. The cloud infrastructure is provisioned for exclusive use by a specific community of consumers from organizations that have shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be owned, managed, and operated by one or more of the organizations in the community, a third party, or some combination of them, and it may exist on or off premises.
Public cloud. The cloud infrastructure is provisioned for open use by the general public. It may be owned, managed, and operated by a business, academic, or government organization, or some combination of them. It exists on the premises of the cloud provider.
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).
All of the above deployment models focus on a single aspect which is who has access to the service. It does not matter if you own the equipment, or if the physical components are hosted on your premises. How or what you use the solution for is also irrelevant. Deployment models only deal with ensuring that the right people have access to the service that is being provided.
A private cloud is akin to a private residence. A home is rarely open to the public, and guests are not the norm. It is usually only the primary resident who has access to the dwelling even if someone else owns the property (even a landlord cannot enter the premises without making arrangements with the tenant).
A community cloud is like a private club. Only members have access to the facilities, but those members all share the facilities and agree to maintain them at a certain standard. No single member can exclude another from one of the club’s resources.
A public cloud is like a municipal park. The facilities and all of the associated resources are available to anyone who can reach the destination. There may be standards of conduct and rules for when resources are available for access, but no one is excluded from the facilities regardless of their public or private affiliations.
A hybrid cloud is the neighborhood where all of these different types of resources reside. You may have several private homes, a local private club for those who seek out membership, and a municipal park for anyone to enjoy. The boundaries are defined, but a person can move freely from their home to access the park, and as long as that person has a membership they can enter the private club as well.
Do not let the decision of what kind of deployment model to use for your cloud infrastructure to be complicated by details beyond who can access what. If only your company’s staff should have access you want a private cloud. If your company and a partner organization are launching a joint project consider a community cloud. If your business model is to give a service away to anyone who is interested you are building a public cloud infrastructure. If you need to combine any of the above models your cloud uses a hybrid deployment. Focus on matching the right deployment model to the right access levels that you need, and you will find it much easier to design your cloud solution correctly.
Be sure to return next week when I will share my opinion on how cloud computing will impact the roles of an IT professional, and to conclude my interpretation of the NIST’s definition of cloud computing.