Cloud Computing: A Technical Perspective

 

In my previous post, I pointed to a simple non-technical introduction to cloud computing. In this article I give a more technical perspective to it.

 

What is Cloud Computing?

 “Cloud computing is Internet (“cloud”) based development and use of computer technology, whereby dynamically scalable virtualized resources are provided as a service over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure ‘in the cloud’ that supports them.” Wikipedia

 

“Cloud computing is emerging at the convergence of three major trends – service orientation, virtualization, and standardization of computing through the Internet. Users will need to understand the cloud options and providers available to them. Vendors will need to evolve their platforms to be cloud-capable, and evolve their business models to maintain their competitive advantage.” Gartner

 

 

Cloud computing emerged as a promising technology in late 2007. Since its emergence, there have been several projects supporting this concept in industry and academia. Some examples (in no specific order) are: Amazon Elastic Compute Cloud (EC2), Amazon Simple Storage Service (S3), ElasticDrive, Enomaly, IBM Blue Cloud, Global Cloud Computing Testbed, Google Docs, Adobe Buzzword, and Google App Engine.

 

Services of Cloud Computing

Conceptually, cloud computing offers a high level of abstraction to its users. It provides some level of service to its users without revealing any details regarding hardware, software, hosting, deployment, and scalability. The services offered in a cloud can be categorized as:

 

SaaS: Software as a Service

Software or applications are hosted on the cloud and are offered to users from a Web Interface (browser). Users can avail these services without having to worry about the application internals or the infrastructure used to deploy them. Examples of SaaS include Facebook and Gmail. This concept can be further enhanced with pay as you go where clients can pay for the quality or quantity of such services used. Examples of this model are SalesForce.com and WebEx.

 

DaaS: Data as a Service

Data in various formats and multiple sources can be seamlessly deployed on the cloud. Users generate and access this data in the same manner they would on their local machines, just that it is eventually stored on the cloud. Examples of this category of service include Amazon Simple Storage Service (S3), Google Docs, and Adobe Buzzword. One can argue that DaaS is a specialized case of SaaS where the software particularly caters to manipulation of data. However, considering its usage and scale I personally feel it justifies its own category.

 

IaaS: Infrastructure as a Service

Infrastructure encompasses some sort of compute or execution service offered by the cloud. It is enabled by the virtualization technology that allows partitioning and sharing of infrastructure resources and scaling them up or down as per client requirements. Examples of IaaS include Amazon Elastic Compute Cloud (EC2).

 

Paas: Platform as a Service

A cloud platform service offers an application development environment to its users enabling them to develop cloud applications sans the low-level details of the cloud. It is analogous to a programming language that shields the programmers from technical details of operating system and underlying hardware. An example of PaaS would be Google App Engine and Microsoft Azure.

 

Characteristics of Cloud Computing

Instant Availability: Without any software or hardware installation users can avail the services out-of-the-box from the cloud

Elastic: Based on user requirements and budget cloud services (SaaS, DaaS, IaaS, PaaS) can be scaled up or down without affecting the service functionality

Pay/Use as you Go: By virtue of its elasticity and virtualization, users can utilize cloud environments and pay for exactly what they need/use

Quality of Service: With experts managing the cloud platforms (and of course charging for it), users can be guaranteed pre-defined quality of services.

 

Technologies in Cloud Computing  

Cloud computing is not a technology by itself. Rather, it is facilitated by the aggregation of several disparate technologies and initiatives.

Web 2.0: The advancements in the way we use Internet has promoted the concepts of cloud computing. With the advent of AJAX and related technologies, rich user interfaces are no longer restricted to local PC-based installations.

Virtualization: New developments in the virtualization technologies (Xen and VMware) have facilitated the concepts in infrastructure sharing and sandboxing without affecting its performance and scalability.

Web Services: The standardization in Web Services world has certainly helped in the proliferation of the service concept being adopted by industry. Not only can these services be used in isolation but can also be embedded by organizations into their SOA architecture.

 

To summarize, cloud computing environments have demonstrated an innovative model of service and resource sharing. They have also been accompanied by a lot of buzz and hype from the industry. However, it is still in its initial stages and needs to go through the standardization phase before it can be adopted en masse via cross compatible clouds.