Benefits, Types of Services and Providers of Cloud Computing

Cloud computing enables companies to consume compute resources as a utility -- just like electricity -- rather than having to build and maintain computing infrastructures in-house. 

Cloud computing promises several attractive benefits for businesses and end users. Three of the main benefits of cloud computing include:

• Self-service provisioning: End users can spin up computing resources for almost any type of workload on-demand.
• Elasticity: Companies can scale up as computing needs increase and then scale down again as demands decrease.
• Pay per use: Computing resources are measured at a granular level, allowing users to pay only for the resources and workloads they use.

Cloud computing services can be Private, Public or Hybrid. 

• Private Cloud Services are delivered from a business' data center to internal users. This model offers versatility and convenience, while preserving management, control and security. Internal customers may or may not be billed for services through IT chargeback. 
• In the Public Cloud Services, a third-party provider delivers the cloud service over the Internet. Public cloud services are sold on-demand, typically by the minute or the hour. Leading public cloud providers include Amazon Web Services (AWS), Microsoft Azure, IBM/SoftLayer and Google Compute Engine.
• Hybrid Cloud is a combination of public cloud services and on-premises private cloud – with automation between the two. The goal of hybrid cloud is to create a unified, automated, scalable environment which takes advantage of all that a public cloud infrastructure can provide, while still maintaining control over mission-critical data.

Although cloud computing  has changed over time, it has always been divided into three broad service categories: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as Service (SaaS).

• IaaS providers such as AWS supply a virtual server instance and storage, as well as application program interfaces (APIs) that let users migrate workloads to a virtual machine (VM). IaaS providers offer small, medium, large, extra-large, and memory- or compute-optimized instances, in addition to customized instances, for various workload needs.
• In the PaaS model, providers host development tools on their infrastructures. Users access those tools over the Internet using APIs, Web portals or gateway software. Common PaaS providers include Salesforce.com'sForce.com, Amazon Elastic Beanstalk and Google App Engine.
• SaaS is a distribution model that delivers software applications over the Internet; these are often called Web services. Microsoft Office 365 is a SaaS offering for productivity software and email services. Users can access SaaS applications and services from any location using a computer or mobile device that has Internet access.