What is cloud computing?

Like its ancestors; “what is client-server?” and “what is SOA?”, questions like “what is cloud computing?” are attracting a near infinite number of viewpoints from technology based marketing, analysts, discussions and blogs.  Here we’ll try to put a clear and simple label (with pictures) on cloud computing.  Feel free to join the debate with your comments below.

Cloud computing is the evolution and convergence of a number of mature and fast maturing technology market threads; virtualization, utility computing and software as a service (SaaS).  Cloud computing already extends beyond the sum of these three to represent the core of what is fast becoming the most disruptive computing model of the 2010′s.

• Virtualization – abstracts from the underlying hardware technology and provides a complete software interface to interact and manage all aspects of physical hardware representation.
• Utility computing – provides access to computing resources on a pay-as-you-go model essentially offers the ability to build and utilize computing infrastructure without investing in computing hardware (similar to utility companies that produce, distribute and sell electricity).
• SaaS – deliver business application functionally over the web at a subscription rate without the need to buy and install software licenses

Cloud computing principles merge these concepts to provide transparent access to required computing software and hardware services typically offered via some form of “pay-as-you-go” model.  While there are numerous technical and commercial representations of cloud offerings on the market, the following principles should be considered common to cloud based solutions:

• No requirement to operate or even understand in detail the underlying hardware technology or core software operating platform - you are abstracted away from the technical complexity of servers, routers, switches, etc.
• You access the cloud service only when you need it and are only charged for your use - pay-as-you-go model
• You are provided with verifiable SLAs and penalty or recovery clauses for used services
• You access cloud services that represent some unit of business input or value to you – underlying transactions, protocols and messaging are hidden in the cloud
• You do not require proprietary software or protocols to use cloud services integrated into your existing business applications domain – everything should be transparently available to existing development methods and practices (JEE, Web 2.0, SOA, etc.)
• You can choose to run cloud computing on your own site and infrastructure, on external hosted resources or on some combination of the two – mix and match onsite versus remote cloud operations

As you explore the benefits of cloud computing to your organization these simple principles may help you test your requirements against the declared offerings of your candidate or selected vendors (including Sensible Cloud).  You should thoroughly test the cloud offering be considered, against many or all of them.

Another definition of Cloud Computing