Cloud computing is a computing paradigm, where a large pool of systems are connected in private or
public networks, to provide dynamically scalable infrastructure for application, data and file storage. With the advent of this technology, the cost of computation, application hosting, content storage and delivery is reduced significantly.
Cloud computing is a practical approach to experience direct cost benefits and it has the potential to
transform a data center from a capital-intensive set up to a variable priced environment.
The idea of cloud computing is based on a very fundamental principal of „reusability of IT capabilities’.
The difference that cloud computing brings compared to traditional concepts of “grid computing”,
“distributed computing”, “utility computing”, or “autonomic computing” is to broaden horizons across
organizational boundaries.
Cloud Computing Models
Cloud Providers offer services that can be grouped into three categories.
1. Software as a Service (SaaS): In this model, a complete application is offered to the customer,
as a service on demand. A single instance of the service runs on the cloud & multiple end users are serviced. On the customers‟ side, there is no need for upfront investment in servers or software licenses, while for the provider, the costs are lowered, since only a single application needs to be hosted & maintained. Today SaaS is offered by companies such as Google, Salesforce, Microsoft, Zoho, etc.
2. Platform as a Service (Paas): Here, a layer of software, or development environment is
encapsulated & offered as a service, upon which other higher levels of service can be built. The customer has the freedom to build his own applications, which run on the provider‟s infrastructure. To meet manageability and scalability requirements of the applications, PaaS providers offer a predefined combination of OS and application servers, such as LAMP platform (Linux, Apache, MySql and PHP), restricted J2EE, Ruby etc. Google‟s App Engine, Force.com, etc are some of the popular PaaS examples.
3. Infrastructure as a Service (Iaas): IaaS provides basic storage and computing capabilities as
standardized services over the network. Servers, storage systems, networking equipment, data centre space etc. are pooled and made available to handle workloads. The customer would typically deploy his own software on the infrastructure. Some common examples are Amazon, GoGrid, 3 Tera, etc.
“A pool of abstracted, highly scalable, and managed compute infrastructure capable of hosting end customer applications and billed by consumption.”
Understanding Public and Private Clouds
Enterprises can choose to deploy applications on Public, Private or Hybrid clouds. Cloud Integrators can play a vital part in determining the right cloud path for each organization.
Public Cloud
Public clouds are owned and operated by third parties; they deliver superior economies of scale to customers, as the infrastructure costs are spread among a mix of users, giving each individual client an attractive low-cost, “Pay-as-you-go” model. All customers share the same infrastructure pool with limited configuration, security protections, and availability variances. These are managed and supported by the cloud provider. One of the advantages of a Public cloud is that they may be larger than an enterprises cloud, thus providing the ability to scale seamlessly, on demand.
Private Cloud
Private clouds are built exclusively for a single enterprise. They aim to address concerns on data security and offer greater control, which is typically lacking in a public cloud.
Cloud Computing Benefits
Enterprises would need to align their applications, so as to exploit the architecture models that Cloud Computing offers. Some of the typical benefits are listed below:
1. Reduced Cost
There are a number of reasons to attribute Cloud technology with lower costs. The billing model is pay as per usage; the infrastructure is not purchased thus lowering maintenance. Initial expense and recurring expenses are much lower than traditional computing.
2. Increased Storage
With the massive Infrastructure that is offered by Cloud providers today, storage & maintenance of large volumes of data is a reality. Sudden workload spikes are also managed effectively & efficiently, since the cloud can scale dynamically.
3. Flexibility
This is an extremely important characteristic. With enterprises having to adapt, even more rapidly, to changing business conditions, speed to deliver is critical. Cloud computing stresses on getting applications to market very quickly, by using the most appropriate building blocks necessary for deployment.