Defining Cloud Computing can be difficult, as each organization often has its own spin on the definition. Despite being hard to define, Gartner Research named Cloud Computing as one of the top technologies to watch in 2010, 2011, and 2012. At its core, Cloud Computing is a technical architecture that meets a specific business need. This chapter traces the roots of Cloud Computing from its origins in mainframe distributed computing, discusses the basics of the Cloud Computing model today, and offers insights for future directions that are likely to be pursued in the Cloud Computing arena. A number of challenges to Cloud Computing are identified, including concerns of security and how to deal with the rise of mobile computing. The chapter ends with recommendations on how to choose which Cloud model is most appropriate to meet your organization’s needs and how to establish a successful Cloud strategy.
TopIntroduction: Defining The Cloud
I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it. ~ Hon. Potter Stewart (U.S. Supreme Court Justice)
Why did Gartner Research place Cloud Computing at the top of the list of most important technology focus areas for the past three years straight (Avram, 2011; Gartner, 2010; McDonald, 2010)? In today’s world of tight budgets and even tighter profit margins, speed to capability is paramount; Cloud Computing has proven effective in enterprise class business environments (Zhang, Zhang, Chen, & Huo, 2010). As Golden (2010) identifies in the Harvard Business Review, Cloud Computing is a key enabler for the business agility so desperately sought since the advent of business operating on Internet time. Cloud Computing is frequently discussed in technology and business trade literature, but general consensus on the definition of Cloud is as nebulous as the image its name conjures.
The University of California, Berkeley describes Cloud Computing as providing the illusion of infinite computing resources to end users on demand while eliminating the upfront investment necessary to implement such services (Armbrust et al., 2009). Buyya, et. al. define Cloud Computing as separate from Grid or Cluster computing environments from a market perspective, identifying Cloud Computing as a function of participating communities entering into a contractual service agreement governed by Service Level Agreements (SLAs) (2009). Neither of these definitions is sufficiently broad to cover the various permutations of Cloud Computing industry today.
Perhaps the most comprehensive definition of Cloud Computing comes from the U.S. National Institute of Standards and technology NIST. According to Mell and Grance (2011), NIST defines Cloud Computing as having five separate characteristics and three basic models as shown in Table 1 and Figure 1.
Table 1. NIST definition of cloud computing
Figure 1. Cloud computing models and technology enablers
The NIST definition of Cloud Computing provides a sufficiently broad definition to cover all types of Cloud models including public, private, and hybrid Cloud approaches and Cloud Computing efforts to improve the efficiency of an organization rather than to drive top line revenue growth. The primary failure of many Cloud Computing definitions (Armbrust et al., 2009) is that they are overly restrictive and focus solely on Cloud Computing as an Internet-based approach toward providing services to other clients and/or end users. While this approach is certainly valid, it ignores the very important use cases of Cloud Computing in the public sector to consolidate costs and save money or of private or public-private hybrid Clouds to enhance security and other services within an organization.
A careful review of the NIST definition of Cloud Computing shows that Cloud Computing is not really a new way of doing business, but a logical extension of computing models established during the 1960s with mainframe computing. Figure 1 traces the technology enablers that are necessary to effect Cloud Computing as defined by NIST. Most of these technology enablers have been in use by industry long before people started talking about the “Cloud.” As anything other than an abstracted infrastructure that performs “stuff” (sometimes referred to as a “Magic Cloud”). Cloud Computing is not magic. It is the logical extension of a business model that has proven useful to businesses since the 1960s; the only real difference is that the technology has improved.