Every now and then, we must have come across the term Cloud. Like “All of the storage is on the cloud” or “We have used this cloud technology to deploy applications” and something like that but what actually is cloud and how it is related to computing?
Cloud is a term referring to accessing Computer Hardware, Information Technology (IT), and Software Applications through a network connection, often by accessing Data Centres set up in different locations using Wide Area Networking (WAN) or Internet connectivity using a remote connection. The computing that relies on shared computing resources rather than having local servers or personal devices to handle applications is called Cloud Computing. In its most simple description, cloud computing is taking services (“cloud services”) and moving them outside an organisation’s local boundary.
HISTORY OF CLOUD COMPUTING
The Cloud is a metaphor for the Internet, derived from its common depiction in network as a cloud outline. The underlying concept dates back to 1960 when John McCarthy opined that “computation may someday be organised as a public utility” (indeed it shares characteristics with service bureaus which date back to the 1960s) and the term The Cloud was already in commercial use around the turn of the 21st century. Cloud computing solutions had started to appear on the market, though most of the focus at this time was on Software as a Service (SaaS technology). The year 2007 saw increased activity, including companies like Google, IBM and a number of universities embarking on a large scale cloud computing research project, around the time the term started gaining popularity in the mainstream press. It was a hot topic by mid-2008 and numerous cloud computing events had been scheduled.
So what really makes a cloud? For a service to be considered as a cloud, it must fulfil these five essential characteristics as follows:
- On Demand Self Service.
- Broad Network Access.
- Resource Pooling.
- Rapid Elasticity.
- Measured Service.
In cloud computing, Cloud Provider controls and monitors all the aspects of cloud service. Resource optimisation, billing, capacity planning, etc, all depend on it.
CLOUD DEPLOYMENT MODELS
Further based on deployment model, clouds can be classified mainly in following ways:
- Public Cloud – These are the cloud in which the cloud provider provides all the cloud infrastructure to general public over the internet. They can be provided free or as ‘pay per use’. Some of the popular cloud service providers are Amazon AWS, Microsoft AZURE and Google GAE.
- Private Cloud – These clouds are maintained solely for a single organisation. They can be created by organisations themselves or by any third party.
- Community Cloud – When two or more organisation have similar cloud requirements, then they can club together to create a cloud infrastructure. These kind of clouds are called community cloud. Example are government organisations coming together to create a single infrastructure for shared pooling of resources.
- Hybrid Cloud – This is combination of more than one type of cloud. For example let’s say that a private cloud has need of more resources than it has on it’s local servers. So it can collaborate with public cloud player like AWS and avail their resources for any duration of time. Such clouds are called hybrid cloud.
CLOUD SERVICE MODELS
Most cloud computing services fall into three broad categories, which are sometimes called the cloud computing stack, because they are built on top of one another. Knowing what they are and how they are different, makes it easier to accomplish our goals.
- Software as a service (SaaS)
- Platform as a service (PaaS)
- Infrastructure as a service (IaaS)
VIRTUALIZATION AND CLOUD COMPUTING
Till now we must have understood what does cloud mean but how is it related to virtualization and how it is different from that?
“Virtualisation is the foundational element of cloud computing and helps deliver on the value of cloud computing”, where as “Cloud computing is the delivery of shared computing resources, software or data -as a service and on-demand through the Internet.”
Virtualization is one of the fundamental technologies that makes cloud computing work. However, virtualization is not cloud computing. We can have clouds without virtualization (Google Apps) and we can have virtualization without Cloud (Hyper-V and VMWare).
But virtualization is very common in cloud style architectures because that’s the way many modern data centers are built but they are not the same thing at all. In the end, Cloud Computing is comparatively new in IT market with a very long way to go…