What is Cloud Computing?
Cloud computing is the on-demand delivery of computing services over the internet rather than buying, owning, and maintaining physical data centers and servers. Computing services can include servers, storage, databases, networking, software, analytics, and intelligence. Cloud computing lowers operating costs and allows for efficient scaling as customers pay on an as-needed basis or pay-as-you-go business model.
Cloud computing has been coined as an umbrella term to describe a category of sophisticated on-demand computing services initially offered by commercial providers, such as Amazon, Google, and Microsoft.
It denotes a model on which a computing infrastructure is viewed as a “cloud,” from which businesses and individuals access applications from anywhere in the world on demand. The main principle behind this model is offering computing, storage, and software “as a service.”
“Cloud is a parallel and distributed computing system consisting of a collection of inter-connected and virtualized computers that are dynamically provisioned and presented as one or more unified computing resources based on service-level agreements (SLA) established through negotiation between the service provider and consumers.”
Benefits of Cloud Computing:
Certain features of a cloud are essential to enable services that truly represent the cloud computing model and satisfy expectations of consumers, and cloud offerings must be as follows:
1. Cost Saving:
Cloud computing eliminates up-front commitment by users, allowing them to request and use only the necessary amount. Services are charged on a short-term basis (e.g by the hrs/min), allowing users to release (and not pay for) resources as soon as they are not needed.
Cloud computing gives the illusion of infinite computing resources available on demand. Therefore users expect clouds to rapidly provide resources in any quantity at any time. In particular, it is expected that the additional resources can be:
(a) provisioned, possibly automatically, when an application load increases
(b) released when loading decreases
The cloud gives you easy access to a broad range of technologies so that you can innovate faster and build nearly anything that you can imagine. You can deploy technology services in a matter of minutes, and get from idea to implementation several orders of magnitude faster than before. This gives you the freedom to experiment, test new ideas to differentiate customer experiences and transform your business.
Most cloud computing services are provided self-service and on-demand. So even vast amounts of computing resources can be provisioned in minutes, typically with just a few mouse clicks, giving businesses a lot of flexibility and taking the pressure off capacity planning.
Types of Cloud Computing:
Cloud Computing is divided into subcategories depending on the physical location of computing resources and who can access those resources are:
1. Public cloud:
Public clouds are owned and operated by a third-party cloud service provider who offers service to the general public. With a public cloud, all hardware, software, and other supporting infrastructure is owned and managed by the cloud provider. These services are accessed and managed using a web browser.
2. Private cloud:
A private cloud is a cloud environment used exclusively by one organization and can be physically located on the organization’s on-site data center. Large enterprises typically choose to keep their data and applications in a private cloud for security reasons. In other cases, private clouds are used in order to comply with company regulations.
Organizations have two options when using a private cloud: it can be set up in the organization’s own data center, or a hosted private cloud service can be used. With a hosted private cloud, a public cloud vendor agrees to set aside computing resources and allow only one customer to use those resources.
3. Hybrid cloud:
A hybrid cloud is a combination of public and private clouds bound together by the technology that allows data and applications to be shared between them. Companies choose hybrid cloud computing for greater flexibility, increased deployment options, and optimized infrastructure, security, and compliance.
Types of Cloud Services:
Cloud computing services are divided into three classes, according to the abstraction level of the capability provided and the service model of providers, namely:
1. Infrastructure as a Service (IaaS):
Offering virtualized resources (computation, storage, and communication) on demand is known as Infrastructure as a Service (IaaS). A cloud infrastructure enables on-demand provisioning of servers running several choices of operating systems and a customized software stack. Infrastructure services are considered to be the bottom layer of cloud computing systems.
2. Platform as a Service (PaaS):
In addition to infrastructure-oriented clouds that provide raw computing and storage services, another approach is to offer a higher level of abstraction to make a cloud easily programmable, known as Platform as a Service (PaaS). A cloud platform offers an environment in which developers create and deploy applications and do not necessarily need to know how many processors or how much memory that applications will be using.
3. Software as a Service (SaaS):
Applications reside on the top of the cloud stack. Services provided by this layer can be accessed by end users through Web portals. Therefore, consumers are increasingly shifting from locally installed computer programs to on-line software services that offer the same functionally. Traditional desktop applications such as word processing and spreadsheet can now be accessed as a service in the Web. This model of delivering applications, known as Software as a Service (SaaS), alleviates the burden of software maintenance for customers and simplifies development and testing for providers.