Cloud Computing Models

Cloud computing models can be spread out into 2 broad categories.

The first being Deployment Models, while the other is service models. These models spell out the modalities involved in making cloud services accessible to you and I (the end-users).

Lets talk about the first model i.e Deployment models (DMs). DMs talk about the accessibility in terms of location to the cloud. It could be public, private or hybrid. We would talk about these using transportation for better illustration.

Public cloud: Think about the public bus. It is likely the cheapest mode of vehicular transportation. It is designed to engage a high number of persons at the same time, who pay for the amount of distance they cover. Of course, it does not have privacy when compared to using your own car, however, it is usually the choice for people who can not yet afford to purchase their own vehicle. This cloud model is handled strictly by 3rd party providers.

private cloud: Can be likened to buying your own car strictly for your own use. Although costly to purchase, it provides you with a high amount of privacy, as you and you alone enjoy your car ride. This cloud model is designed and built strictly for an individual enterprise/company.

Hybrid Cloud: As the name implies, is a bridge between the public and private cloud. A good illustration would be the cab hailing service, where you still enjoy the best of both worlds, in terms of enjoying an element of privacy for that particular trip, but also paying for that particular journey alone and not having to buy the entire cab. Hybrid combines the benefit of 3rd party providers either partially or entirely, and combines it with private cloud to enjoy the best of both worlds.

Now let's talk about the second model i.e service models...

This refers to the means through which cloud computing is offered, each of which satisfy specific business requirements.

Infrastructure-as-a-Service (IaaS): These provide basic computing, networking and storage services over the internet on a pay-per-use basis. Think of it as renting computers and servers. You leave the management of infrastructure to the cloud providers. Examples include Amazon's EC2 and Google cloud platform.

Platform-as-a-Service (PaaS): This particular service model, provides the environment for developers to deploy their applications without the need for installing IDEs (Integrated Development Environments), so they can deploy their programs and applications as quickly as possible. It is highly customizable and includes examples such as Microsoft Azure, and Google app engine. 

Software-as-a-Service (SaaS): This refers to cloud services offered and managed entirely by 3rd party providers. All the customer/user needs to do is login to access it. This can provide a huge relief for companies using the service as they do not concern themselves with issues such as software maintenance and infrastructure management. Examples include Gmail Email service, and the Office 360 package.