Cloud computing fundamentals (Part I)

 

In the last few years, Information Technology (IT) has embarked on a new paradigm — cloud computing. Although cloud computing is only a different way to deliver computer resources, rather than a new technology, it has sparked a revolution in the way organizations provide information and service.

Originally IT was dominated by mainframe computing. This sturdy configuration eventually gave way to the client-server model. Contemporary IT is increasingly a function of mobile technology, pervasive or ubiquitous computing, and of course, cloud computing. But this revolution, like every revolution, contains components of the past from which it evolved.

Thus, to put cloud computing in the proper context, keep in mind that in the DNA of cloud computing is essentially the creation of its predecessor systems. In many ways, this momentous change is a matter of "back to the future" rather than the definitive end of the past. In the brave new world of cloud computing, there is room for innovative collaboration of cloud technology and for the proven utility of predecessor systems, such as the powerful mainframe. This veritable change in how we compute provides immense opportunities for IT personnel to take the reins of change and use them to their individual and institutional advantage.

What is cloud computing?

Cloud computing is a comprehensive solution that delivers IT as a service. It is an Internet-based computing solution where shared resources are provided like electricity distributed on the electrical grid. Computers in the cloud are configured to work together and the various applications use the collective computing power as if they are running on a single system.

The flexibility of cloud computing is a function of the allocation of resources on demand. This facilitates the use of the system's cumulative resources, negating the need to assign specific hardware to a task. Before cloud computing, websites and server-based applications were executed on a specific system. With the advent of cloud computing, resources are used as an aggregated virtual computer. This amalgamated configuration provides an environment where applications execute independently without regard for any particular configuration.

Why the rush to the cloud?

There are valid and significant business and IT reasons for the cloud computing paradigm shift. The fundamentals of outsourcing as a solution apply.

• Reduced cost: Cloud computing can reduce both capital expense (CapEx) and operating expense (OpEx) costs because resources are only acquired when needed and are only paid for when used.
• Refined usage of personnel: Using cloud computing frees valuable personnel allowing them to focus on delivering value rather than maintaining hardware and software.
• Robust scalability: Cloud computing allows for immediate scaling, either up or down, at any time without long-term commitment.

Cloud computing building blocks

The cloud computing model is comprised of a front end and a back end. These two elements are connected through a network, in most cases the Internet. The front end is the vehicle by which the user interacts with the system; the back end is the cloud itself. The front end is composed of a client computer, or the computer network of an enterprise, and the applications used to access the cloud. The back end provides the applications, computers, servers, and data storage that creates the cloud of services.

Layers: Computing as a commodity

The cloud concept is built on layers, each providing a distinct level of functionality. This stratification of the cloud's components has provided a means for the layers of cloud computing to becoming a commodity just like electricity, telephone service, or natural gas. The commodity that cloud computing sells is computing power at a lower cost and expense to the user. Cloud computing is poised to become the next mega-utility service.

The virtual machine monitor (VMM) provides the means for simultaneous use of cloud facilities (seeFigure 1). VMM is a program on a host system that lets one computer support multiple, identical execution environments. From the user's point of view, the system is a self-contained computer which is isolated from other users. In reality, every user is being served by the same machine. A virtual machine is one operating system (OS) that is being managed by an underlying control program allowing it to appear to be multiple operating systems. In cloud computing, VMM allows users to monitor and thus manage aspects of the process such as data access, data storage, encryption, addressing, topology, and workload movement.

Figure 1. How the Virtual Machine Monitor works

These are the layers the cloud provides:

• The infrastructure layer is the foundation of the cloud. It consists of the physical assets — servers, network devices, storage disks, etc.Infrastructure as a Service (IaaS) has providers such as the IBM® Cloud. Using IaaS you don’t actually control the underlying infrastructure, but you do have control of the operating systems, storage, deployment applications, and, to a limited degree, control over select networking components.

  Print On Demand (POD) services are an example of organizations that can benefit from IaaS. The POD model is based on the selling of customizable products. PODs allow individuals to open shops and sell designs on products. Shopkeepers can upload as many or as few designs as they can create. Many upload thousands. With cloud storage capabilities, a POD can provide unlimited storage space.

• The middle layer is the platform. It provides the application infrastructure. Platform as a Service (PaaS) provides access to operating systems and associated services. It provides a way to deploy applications to the cloud using programming languages and tools supported by the provider. You do not have to manage or control the underlying infrastructure, but you do have control over the deployed applications and, to some degree over application hosting environment configurations.

  PaaS has providers such as Amazon's Elastic Compute Cloud (EC2). The small entrepreneur software house is an ideal enterprise for PaaS. With the elaborated platform, world-class products can be created without the overhead of in-house production.

• The top layer is the application layer, the layer most visualize as the cloud. Applications run here and are provided on demand to users. Software as a Service (SaaS) has providers such as Google Pack. Google Pack includes Internet accessible applications, tools such as Calendar, Gmail, Google Talk, Docs, and many more.