The Understanding Problem
While presenting a keynote address to an audience of information-technology people from the higher-education sector, a senior representative of a super-vendor smiled handsomely and said:
“The cloud means different things to different people.”
That is a very unhelpful statement. Perfectly-clear criteria define what cloud computing is, and therefore what it is not. There is still widespread marketplace confusion about the benefits, patterns, and use-cases of cloud computing. This confusion is caused partly by people lacking or losing reference to the fundamental definition of what cloud computing is.
The Elastic Definition
In 2010, the Burton Group defined cloud computing as:
“The set of disciplines, technologies, and business models used to deliver IT capabilities (software, platforms, hardware) as an on-demand, scalable, elastic service.”
This definition is as good as any that i’ve seen, and it is accompanied by a set of five essential characteristics, features of a service that must be present if the service is able to be defined as cloud computing:
- it uses shared infrastructure
- it provides on-demand self-service
- it is elastic and scalable.
- it is priced by consumption.
- it is dynamic and virtualised.
The NIST definition published in 2011 also includes essentially the same set of five essential characteristics that must be present for a service to be described as cloud computing:
- on-demand self-service
- broad network access
- resource pooling
- rapid elasticity
- measured service
Both NIST and Burton go on to describe service models (e.g., IaaS, PaaS, SaaS) and deployment models (e.g., private cloud, hybrid cloud, community cloud), but the defition and the essential characteristics must be present for a service to be a cloud computing service.
Abolishing the Confusion
Abolishing the confusion should be easy: engage with a clear sense of the essential characteristics that must be present for a service to be considered as a cloud service… and be equally clear about when it really matters whether or not a service falls into the official definition of cloud computing.
The CloudU initiative curated by Ben Kepes (@benkepes on Twitter) with Rackspace is a good resource for raising globally the level of cloud understanding. CloudU is part of the Rackspace knowledge centre at http://www.rackspace.com/knowledge_center/cloudu/
Some other selected useful references are detailed below:
- Blakley, B. & Reeves, D. (2010) Defining Cloud Computing, Burton Group Research
- Kaskade, J. (2009) Defintion of Cloud Computing — Again, Jim Kaskade’s blog, http://jameskaskade.com/
- Mell, P. & Grance, T. (2011) The NIST Definition of Cloud Computing, National Institute of Standards and Technology, U.S. Department of Commerce, NIST Special Publication 800-145, http://csrc.nist.gov/publications/nistpubs/800-145/SP800-145.pdf