Cloud computing is a rather recent technology that has taken the world by storm.
To put things in simple terms, it is the use of computing assets like hardware and software that can now be delivered as services over the internet. Everything you see on the web today is a basic or advanced form of cloud computing.
Social networking sites promote cloud computing. The fact that you can store your pictures and videos on the websites indicates that you use the website’s storage system to store your data. Even something as simple as our emails is stored in the website’s servers.
The name ‘Cloud computing’ is derived from the fact that a cloud shaped figure is used to represent this technology.
Cloud computing is now a new field that’s all ready to be explored and implemented for better performing, sophisticated and much more efficient systems. It is nothing like autonomic computing, utility computing or grid computing.
This platform is much more independent than the others. The unique feature of cloud is that it can be hosted by anyone, anywhere; it can be a service provider, an enterprise or a body of government. The best examples of cloud computing are online applications, which have been installed on another server, but you as the user can access it anyway from anywhere.
Today, we are going to have a closer look at cloud systems and how they function, the different architectures and the ease with which these perform for the users of cloud systems.
So, what is Cloud Computing?
‘Cloud Computing’ can be called a category of very sophisticated form of on-demand services (computing) that are offered by commercial service providers in the industry today.
It represents a model called the ‘cloud’ which is a computing infrastructure from which individual users as well as businesses can access applications anywhere, anytime.
Cloud Computing can be defined as a ‘data centre’ which:
- Assembles a ‘pool’ of various computing services and resources that subscribers share. The services are charged for as per their use and are paid for by the users.
- Is usually distributed geographically in such a manner that is both transparent and ensures faster performance and ease of availability to the users/ subscribers.
- Are programmed such that the configuration of the services and resources occur as self-services. The request of the user is processed in an automated manner and is delivered in one or two parts of a second.
- All the services and resources are provided virtually, even though they may seem to be physical (disks, storage systems, servers and network segments), all of these are actually the virtual implementations of the services and resources on a physical infrastructure that lies underneath.
- The practical implementation of the infrastructure doesn’t change. But the services and resources keep changing constantly.
- The services and resources in a cloud system are both a physical metaphor (storage systems, disks, servers, network segments) and abstract metaphor (email functions, message-queue functions, blob-storage functions as well as multicast functions), all of which may be inter-mixed to suit the user’s requirements.
Cloud Computing: Service Delivery Models
The services in cloud computing are divided into three categories, depending on the level of abstraction and capability of the architecture and performance:
- Software as a service model
- Platform as a service model
- Infrastructure as a service model
These models are nothing but layers of architecture where the services of the higher layers consist of the services of the lower layers plus some additional ones.
A core or central middleware can manage physical assets and the virtual machines can be deployed on them. A VM provides the necessary features that support the ‘pay as you go’ payment model of the cloud computing architecture.
The development of cloud models consists of infrastructure services that provide application development and the capacity to deploy them.
On this level, a number of programming models, APIs, libraries and mash up editors facilitate the creation of a wide range of commerce, scientific and web applications. Once these are deployed in a cloud system, these applications can be used by the end users.
Model 1: Software as a Service model (SaaS)
A software as a service model offers applications that are hosted on the cloud infrastructure as internet-based services for the end users without the requirement of installing the applications on the user’s systems. The applications are hosted on a remote server that the user can access.
This model is hosted on top of the other two models or is hosted directly on the cloud system.
This service model of application development refers to software for business rather than for customers, which can be categorized as Web 2.0.
Eliminating the need of installing and running the applications on the user’s system is an economic way for many small business houses to get benefits and make profits when it comes to using commercial software for their business purposes.
Model 2: Platform as a Service model (PaaS)
A platform as a service model is a level above the software as a service model.
This system allows its users to have access to software and applications installed and run on remote servers as well as provide the scope to develop a new system/application using the existing ones. It offers the flexibility required to develop, deploy, operate and change the applications over the World Wide Web.
This service model can be hosted on top of the Infrastructure as a service model or upon the cloud infrastructure directly.
Model 3: Infrastructure as a Service model (IaaS)
The ultimate service model in the cloud computing system is the Infrastructure as a service model. In this model, the user can use the software and applications, alter and develop new ones and store the necessary information as well. This system is hosted on the cloud infrastructure directly.
This model is based on the virtualization technology. It offers virtual assets like storage, computation and communication that are a complete package that’s necessary for any business to sustain.
A cloud based infrastructure provides the on-demand provisioning of servers that run on various choices of OS and a sophisticated software stack. The infrastructure services are the bottom-most layer of the cloud computing system.