Cloud Computing

What is it?

The practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer.

the ideologies and principles of cloud computing – “On demand availability”, “As a service” and “Pay for the usage”.  


Which are Models  in it?

Infrastructure as a Service (IaaS)
This is the most fundamental layer which forms the building block of the cloud. It mainly comprises of physical resources such as Storage, Network devices, compute servers, etc. All these computing resources are available on demand, where a user pays as per his usage.

Platform as a Service (PaaS)
The central layer in the cloud Is the platform. Here there is no control over the underlying infrastructure but you can access the deployed applications. Hence this provides the entire runtime environment on demand which could be a development or test environment. Hence in this model, most commonly you would have a VM that contains the complete environment like OS, required middleware, etc. available when you need it.


Software as a Service (SaaS) 

The topmost layer here is the application layer, which is generally visible to any user. Here, applications / products are available to the user on demand via the internet. Hence instead of having to acquire licenses for a particular user, this proves to be the most cost effective way of making sure that the license is always in use. Examples of this are Gmail, Google docs, Photoshop, etc.

Types of Clouds

1. Private Cloud: Here, computing resources are deployed for one particular organization.  This method is more used for intra-business interactions.  Where the computing resources can be governed, owned and operated by the same organization.
2. Community Cloud: Here, computing resources are provided for a community and organizations. 
3. Public Cloud: This type of cloud is used usually for B2C (Business to Consumer) type interactions.  Here the computing resource is owned, governed and operated by government, an academic or business organization. 
4. Hybrid Cloud: This type of cloud can be used for both type of interactions -  B2B (Business to Business) or B2C ( Business to Consumer). This deployment method is called hybrid cloud as the computing resources are bound together by different clouds.