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The last cloud computing definition you'll ever need

What is cloud computing? This overview defines cloud for once and for all -- until the next round of vendor hype.

As the classic saying goes, we’ve all got one. Usually it's an opinion, but in this case it's a personal definition of cloud computing.

The lack of a settled cloud definition means businesses need to make their services work for them.

Despite a rapidly growing degree of genuine interest, pundits can’t seem to agree on a proper meaning. Over the years, "cloud" has become a vague and flexible term that does not reference anything in particular. This has allowed some providers to take advantage of the positive press and push any related services as "cloud," while other companies might shun the term entirely out of self-consciousness or concerns about cloud computing's future.

Meanwhile, the National Institute of Standards and Technology (NIST) is the most famous purveyor of the "cloud" definition, publishing a new one every year in an attempt to cover all the characterizations and opinions that exist in the marketplace. The most recent edition, however, clocks in at a lengthy 790 words, and NIST acknowledges its definition's fluidity with two introductory notes about cloud being an "evolving paradigm." The organization is also actively seeking public comments for the in-progress sixteenth version.

All this back and forth leads to the question: When is a cloud not a cloud?

The fact remains that both "cloud" and "cloud computing" are imprecise, adaptable terms that can be modified to fit the needs and agendas of certain individuals within the marketplace. And with no single, accepted definition, products and services may not effectively provide the benefits clients are seeking for their business.

What is cloud computing, and what just looks the part?
So how far will "cloud" go as a buzzword? There is already a risk of genuinely helpful providers finding themselves lost amid the chatter of derivative offerings, not to mention clients mistakenly pursing a lesser product because it is considered "cloud."

Further complicating matters is the fact that most major developments in enterprise computing contain at least a few "cloud-like" components. When you're deciding between different "cloud" services for your IT environment, take note of the table below and make sure you understand which of their major traits are cloudy in nature, and which are just fog:

  Cloud Not cloud
Infrastructure as a Service • Remote delivery
• Multi-tenancy
• Scalability and load-balancing
• Eliminates need for on-site facilities
• Some would argue this is more on-demand delivery of virtual machines than pure cloud
• Only some vendors offer truly automated elasticity, e.g. Amazon Auto-Scaling
Managed hosting • Remote delivery
• Eliminates need for on-site facilities
• Multi-tenancy
• Provisioning and de-provisioning not automatic
• Immediate scalability often not available
Virtualization • Multi-tenancy
• Elasticity
• Scalability
• Provisioning and de-provisioning not automatic
• Elasticity not infinite and subject to hardware constraints
Private cloud • Multi-tenancy
• Remote delivery via intranet
• Elasticity
• Scalability
• In most cases, it is on-demand virtualization
• Billing mechanisms often not in place; reliance on chargeback
• Few companies can achieve economies of scale necessary to make this work
• Elasticity not infinite and subject to hardware constraints
File sharing and collaboration • Remote delivery and access
• Multi-tenancy
• Elasticity is limited by hardware and space constraints
Email • Remote delivery and access
• Multi-tenancy
• Elasticity
• Scalability
• Provisioning and de-provisioning not automatic
• Immediate scalability often not available
• Often more managed hosting than "cloud"
Voice services • Remote delivery
• Multi-tenancy
• Scalability
• Many services require additional customization and are incapable of working "right out of the box"
Mainframe • Multi-tenancy
• Elasticity
• Provisioning and de-provisioning not automatic
• Hardware constraints exist
• Risk of a single point of failure within the infrastructure
• Today, could be synonymous with private cloud

One simple and sensible way to view "cloud" is as a new evolution of IT service delivery from a remote location, either over the Internet or an intranet, involving multi-tenant environments enabled by virtualization. Cloud architecture is underpinned and enabled by commodity hardware, on top of which virtual machines are provisioned and offered to consumers. Elasticity is an important component of cloud computing, but it is both a feature and a natural result of the main drivers of cloud computing: economies of scale, improved efficiency and speed.

"Cloud" has become a vague and flexible term that does not reference anything in particular.

That said, the lack of a settled and universal "cloud" definition means businesses need to make their cloud services work for them. A business needs to define its goals and objectives for a cloud computing offering, as well as the benefits sought, and look for providers that will maximize those advantages. Simply being located in the cloud is not enough; nor should the possibility of cost savings be a permanent, compelling reason to adopt. Even though cloud is a new delivery method, it must conform to the old rules of producing superior business value at cost or risk being re-obscured.

IT pundits will continue to argue over a single, appropriate definition, but that does not mean you have to sit around and listen. Make the cloud work for you and your business, and let everyone else argue over what is and isn’t cloud.

Nick Giglia is a consultant to Citihub and the founder and CEO of Fahros, Inc., which seeks to revolutionize corporate IT management for the cloud paradigm. His main competencies and interests, in addition to cloud computing, are virtualization, desktop support and systems architecture. Prior to Citihub, he worked in platform architecture and infrastructure at Deloitte Consulting, where he wrote about and helped build the practice around next-generation data centers. Nick can be reached at njgiglia@gmail.com.

Lucian Lipinsky de Orlov is an associate partner at Citihub, Inc., a leading specialist IT consultancy focused on the financial services industry. Lucian specializes in enterprise desktop migrations and helping clients implement cloud-based solutions. Prior to Citihub, he was a senior manager at Deloitte Consulting and a principal consultant at IBM. Lucian can be contacted at llipinsky@citihub.com.

This was last published in February 2011

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