Published:
July 01 2010, 08:23 AM
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1 Comment(s)
by
Steve Romero
Cloud Computing is easily the hottest information technology topic in Enterprises today. Interest and discussion abounds from every imaginable source and from every possible direction. There has been a flurry of theory, fact and fantasy which I don't find surprising. It seems to accompany anything and everything new when it comes to IT. But what I do find surprising is the all too frequent suggestion that Cloud Computing is complex, confusing, or difficult to understand. I beg to differ.
There have been a number of good posts attempting to dispel the notion that the new IT-induced cumulus is nebulous. One of the best is by @PeterKretzman. The post is titled, "Cloud computing: misunderstood, but really not that complicated a concept": http://bit.ly/94JMSe.
I believe Cloud Computing can be explained quite simply. And to prove so I need only reference the great work done by Peter Mell and Tim Grance at the National Institute of Standards and Technology (NIST), "The NIST Definition of Cloud Computing", Version 15, 10-7-09 http://csrc.nist.gov/groups/SNS/cloud-computing/.
First, here is their straightforward definition (and of all the definitions I've seen, it is easily my favorite):
"Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction."
In addition to this great definition of Cloud Computing, you need only remember this: 5-3-4. (Yes, I know that 3-4-5 or 5-4-3 would be easier to recall, but I did not want to change the sequence established at NIST.)
- 5 Essential Characteristics
- 3 Service Models
- 4 Deployment Models
Cloud Computing has 5 essential characteristics. (Note the word, essential. Peter and Tim aren't as iron-fisted, but I insist that if any of these characteristics is missing, it isn't Cloud Computing.)
On-demand self-service. A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service's provider.
Broad network access. Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs).
Resource pooling. The provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Examples of resources include storage, processing, memory, network bandwidth, and virtual machines.
Rapid elasticity. Capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time.
Measured Service. Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported providing transparency for both the provider and consumer of the utilized service.
Cloud Computing is composed of 3 Service Models:
Cloud Software as a Service (SaaS). The capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based email). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.
Cloud Platform as a Service (PaaS). The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations.
Cloud Infrastructure as a Service (IaaS). The capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls).
Cloud Computing is composed of 4 Deployment Models:
Private cloud. 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.
Community cloud. The cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on premise or off premise.
Public cloud. The cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.
Hybrid cloud. The cloud infrastructure is a composition of two or more clouds (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).
That's it. Notice the lack of techno-speak. Notice the lack of jargon. Notice the lack of hyperbole. Notice how simply Cloud Computing can be explained.
And I admit this post is very simple as well. I only addressed the easiest aspect, the "what" of Cloud Computing. Thank you NIST. For answers to the far more complex questions of the "how-who-when-where-why" of Cloud Computing, you'll need to talk to my compatriots at CA Technologies. I am certain they would love to tackle those more demanding questions with you.
Steve Romero, IT Governance Evangelist