On a nice day, you may have sunshine and a few clouds in the sky. These visible masses of droplets of water may dissipate and it starts to rain water, a liquid that’s essential to life. An elephant in the middle of the dessert is not going to care where the rain is coming from so long as he is quenched of his thirst. Now you’re beginning to think, “what does this have to do with cloud computing? why is it even called the cloud? For one, a cluster of servers with which virtual instances of servers run can be considered the “droplets of water”. So the cluster of servers make up a cloud and the rain is the resource and how a user might benefit from it. Also, note the difference here is that you can tap into cloud resources anytime you want, making it “rain”, so to speak, on whim.
Generally, users of the cloud would not care where the resources are coming from, only that they have these resources to complete the job. Take for example the popular gmail service, they have thousands of computers connected to networks, running many many kinds of software. So when you access your email, you’re not thinking “I wonder that what specific computer or server the application is running off of”, it’s more probable that you’re concerned about writing that email to a professor for a deadline extension then anything else.
There are three types of clouds: Private, public, and a hybrid between the two. As the name implies, a private cloud enables the user to their own infrastructure or site. This is ideal for businesses that deal with private data such as bank accounts or simply want to have privacy within the network. The public cloud, on the other hand, is very similar to how a power company provides its service as a utility. The cloud here is a shared pool of networks, servers, storage, applications, and services available to multiple users. Lastly, the hybrid cloud, combines features of both private and public clouds – a company may use an internal cloud to share resources over its network but extend the capabilities during peak processing times. For example, gmail, the service is provided to the public but user data is stored privately and securely behind firewalls.
A cloud is not a permanent fixture in the sky. Similarly, the idea of virtualization and usage of the cloud is meant to be ephemeral or in other words, fleeting. It is easy to wipe a computer’s memory or restore it. It is not, however, easy to replace physical machines as it is costly and inefficient.
