Cloud Computing - Overview

CLOUD COMPUTING – DEFINITION

Cloud computing is a model for enabling ubiquitous, 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. This cloud model is composed of five essential characteristics, three service models, and four deployment models (Mell and Grance, 2011).

What is Cloud Computing?

Imagine your PC and all of your mobile devices being in sync—all the time. Imagine being able to access all of your personal data at any given moment. Imagine having the ability to organize and mine data from any online source. Imagine being able to share that data—photos, movies, contacts, e-mail, documents, etc.—with your friends, family, and co-workers in an instant. This is what personal cloud computing promises to deliver.

Whether you realize it or not, you're probably already using cloud-based services. Pretty much everyone with a computer has been. Gmail and Google Docs are two prime examples; we just don't think of those services in those terms.

In essence, personal cloud computing means having every piece of data you need for every aspect of your life at your fingertips and ready for use. Data must be mobile, transferable, and instantly accessible. The key to enabling the portable and interactive you is the ability to synch up your data among your devices, as well as access to shared data. Shared data is the data we access online in any number of places, such as social networks, banks, blogs, newsrooms, paid communities, etc.

Ultimately, your personal cloud—which includes everything from your address book and music collection to your reports and documents for work—will connect to the public cloud and other personal clouds. Everything connects. That means every place on the Internet you interact with, as well as every person you interact with can be connected. This includes your social networks, bank, university, workplace, family, friends—you name it.

Of course, you will determine what you show the public and what you keep private. Clusters of personal clouds will form new social networks that will likely have a lot more privacy settings than Facebook, especially if these clusters are family or business oriented. (Privacy will be a huge issue as personal clouds hit critical mass.)

Eventually, your devices will learn about you and eventually intuit what you are doing, where you are going, and what you intend to do when you get there. Think of all this as helpful… not creepy.  Cloud computing is still evolving and yet to get to this stage.

(Source: Tadjer, 2010)

ESSENTIAL CHARACTERISTICS

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 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, tablets, laptops, and workstations).

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 data-center). Examples of resources include storage, processing, memory, and network bandwidth.

Rapid elasticity

Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.

Measured service

Cloud systems automatically control and optimize resource use by leveraging a metering capability1 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.

DEPLOYMENT MODELS / TYPES OF CLOUDS 

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).

(Source: Mell and Grance, 2011)

REFERENCES:

Mell, Peter and Grance, Timothy (2011), “The NIST Definition of Cloud Computing”, Recommendations of the National Institute of Standards and Technology, NIST, U.S. Department of Commerce, Special Publication 800-145, September 2011

Tadjer, Rivka (2010), “What Is Cloud Computing?”, PCMag.com, Available at: http://www.pcmag.com/article2/0,2817,2372163,00.asp, Accessed: August 14, 2012-08-14