cloud computing

This definition is part of our Essential Guide: The world of microservices and container technologies
Contributor(s): Stephen J. Bigelow

Cloud computing is a general term for the delivery of hosted services over the internet.

Cloud computing enables companies to consume a compute resource, such as a virtual machine (VMs), storage or an application, as a utility -- just like electricity -- rather than having to build and maintain computing infrastructures in house.

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

  • Self-service provisioning: End users can spin up compute resources for almost any type of workload on demand. This eliminates the traditional need for IT administrators to provision and manage compute resources.
  • Elasticity: Companies can scale up as computing needs increase and scale down again as demands decrease. This eliminates the need for massive investments in local infrastructure which may or may not remain active.
  • Pay per use: Compute resources are measured at a granular level, allowing users to pay only for the resources and workloads they use.

Cloud computing deployment models

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 the management, control and security common to local data centers. Internal users may or may not be billed for services through IT chargeback.

In the public cloud model, a third-party provider delivers the cloud service over the internet. Public cloud services are sold on demand, typically by the minute or hour. Customers only pay for the CPU cycles, storage or bandwidth they consume. 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 orchestration and automation between the two. Companies can run mission-critical workloads or sensitive applications on the private cloud while using the public cloud for bursting workloads that must scale on demand. The goal of hybrid cloud is to create a unified, automated, scalable environment that takes advantage of all that a public cloud infrastructure can provide while still maintaining control over mission-critical data.

Cloud computing service categories

Although cloud computing has changed over time, it has been divided into three broad service categories: infrastructure as a service (IaaS), platform as a service (PaaS) and software as a 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. Users have an allocated storage capacity and can start, stop, access and configure the VM and storage as desired. 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 these tools over the internet using APIs, web portals or gateway software. PaaS is used for general software development, and many PaaS providers will host the software after it's developed. Common PaaS providers include's, AWS Elastic Beanstalk and Google App Engine.

SaaS is a distribution model that delivers software applications over the internet; these applications 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.

A brief summary of what IaaS,
PaaS and SaaS are and how to
use each.

Cloud computing security

Security remains a primary concern for businesses contemplating cloud adoption -- especially public cloud adoption. Public cloud providers share their underlying hardware infrastructure between numerous customers, as public cloud is a multi-tenant environment. This environment demands copious isolation between logical compute resources. At the same time, access to public cloud storage and compute resources is guarded by account logon credentials.

Many organizations bound by complex regulatory obligations and governance standards are still hesitant to place data or workloads in the public cloud for fear of outages, loss or theft. However, this resistance is fading as logical isolation has proven reliable and the addition of data encryption and various identity and access management (IAM) tools has improved security within the public cloud.

This was last updated in October 2016

Next Steps

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its very useful to us. thanks for giving this type of information.i need a doubt atpresent what is the feture of cloud computing in I.T sector?
Its articles like this that confuse the matter even further. Cloud services is an on demand easily accessible set of resources which is scalable. It does not have to be Internet facing nor is just built on the three strands - one area which is missed out is ITaaS which enables businesses to deliver these scalable solutions themselves without having to pay out needlessly.
Cloud computing is nothing more than what we had in the 70's but then it was called TSO (Time Sharing Option).
Thank goodness someone remembered the time sharing schemes that were prominent in the mainframe/mini-computer era. And your right, the "Cloud" et al. is nothing more than the client/server version of the old timeshare. They both sought/seek to maximize the use of expensive resources while minimizing (in theory) costs, though I question whether the "Cloud" model really saves that much money. Indeed, I suspect that many firms are thinking, "you guys are charging us WHAT?" Or they have wholly legitimate concerns about security. It's hard enough to keep up with THAT problem on your own.
Now the computer systems related terminologies has become difficult to determine the first time my eyes goes on those words!!!
wouldn't cloud computing make it easy to implement government regulations that can destroy businesses around the world?
it is my first time of actually taking time to find out what cloud computing is about in terms of definition and component. I am truly impressed with your explanations. it is clear and contains the essentials. thank you.
Folks, if you remember the mainframe age, exactly we are going back to that age... This is what could computing is..
Great Post! It explains all the basics in a nice and short summary.
helpful information
thanks for the neatly , simply , straight forward answers also helps for my exams
i am saying these from my bottom of heart it really worth for me
What should be the minimum qualification
to do CLOUD computer course
Thanks for providing such an informative article on coud computing. I have been looking for a straigtforward explanation for a long time. Two other articles that also assisted me in understanding are and . There are so many definitions on the internet it is really confusing so thanks for creating an easy to follow one.
Cloud computing is a term techies seem that they know but actually they don't exactly how cloud computing works. Cloud computing comes in picture when other realistic systems don't work or work miserably when data backup is needed for large sized or even small ones. Cloud computing for small business have been implemented in many companies too. You can check details about it :
Ok, a nice article but it doesn't answer the question the article poses: "What is Cloud Computing?"
Cloud computing is expensive. I don't see startups or small-to-mid size businesses using it. Our organization leases the use of a virtual computer on a cloud server so that we didn't have to purchase a computer. We've been pleased with Windows Azure. We "pay as you go." Set up was complicated. We hired a consultant to come in and assess our cloud infrastructure. It worked out well. If you're thinking about whether or not cloud computing will benefit your enterprise, this is a good resource. It helped us decide:
Very true. I agree that elasticity and centralized control are what distinguish cloud computing from traditional hosting. Enterprises of all types and sizes are finding the cloud a safe and cost-effective option for managed IT support. One of the major reasons for such high levels of trust is the ability to use and pay for only as much service as required. Companies know that they will be paying for what they want. Plus, when it comes to security, the cloud is way more efficient compared to traditional IT models!
for what process cloud computing used for?
Basically It is a method of configuring servers in a flexible way to allow for the most affordable, scalable, and reliable web infrastructure.
Cloud computing has found its prominence owing to many benefits that it provides. It will be really appreciable for most of us if we concentrate on the result rather than the efforts. Cloud does the exact. The major requirement remains a greater bandwidth.
It is very clear and great description about cloud hosting. This is very good for the people who want to know more about cloud computing.Cloud is one technological model that assures data backup and disaster recovery solutions to the users.
It explain very well and I hope people understand, Public cloud is good for temporary use, No one want to use Public cloud 24/7-365 days and pay lot on money to vendor. If you need server for your Dev/test, it is good to use public cloud but for your company major applications/Databases/Financial data still required Private cloud (Company Own Data Center). Good to go for Hybrid cloud.
What are the biggest benefits and challenges your organization has faced while using cloud computing services?
i think it will be a threat to jobs of IT administrators..
Cloud computing always helps to Small and Medium businessman who have not more money to hire any accountant for manage our accounting works. Cloud computing have more of more advantages in which cost effective hosting services, reliable hosting, more flexible and data security are coming. These advantages are make it special to another type hosting services.


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