Cloud isn’t a technology; it’s a business model. Cloud computing is transforming IT and business alike. Because of this, many vendors now claim to be “as a service” or “cloud”. This series of posts explain exactly what cloud is, how you get it, and what it does.

Cloud computing is a new business model powered by new technologies. It’s an on-demand, self-service, “pay as you go” model for access to hosting infrastructure (networks, servers, storage, operating systems, applications, support, administration). Cloud providers deliver infrastructure, platforms and applications as a service.

With Cloud computing the business pays only for what it uses. Compared to traditional models, cloud can deliver five– to ten-fold improvements in costs and time to market (although 20% is more realistic). Pay-as-you-go eliminates over– and under-provisioning capacity. Over-provisioning wastes money. It also reduces funds available– for other investments. Under-provisioning increases time to value and can result in lost revenue as customer experience degrades. Automated capacity management is built into the cloud. Adding or removing infrastructure quickly in response to demand offers agility and cost effectiveness traditional IT cannot match. A cloud has five essential characteristics, three service models, and four deployment models. Each has its pros and cons. cloud can reduce the time, money, and the number of people it takes to build and deploy applications and related hosting infrastructure. Yet cloud is not always the right solution.

What You Need to Know

Five key feature characteristics define the cloud.

1. On-demand self-service to infrastructure, platforms and applications delivered by a “pay-as-you-go” model based on usage.
2. Broad access through mobile phones, tablets, laptops, and workstations.
3. Resource pooling and automation to combine resources into managed services.
4. Rapid elasticity that scales automatically and quickly with demand.
5. Measured service with usage monitored, controlled, and reported.

Three cloud service models define decreasing levels of control.

1. Infrastructure as a Service (IaaS) provides network, server, storage, and middleware that IT uses to deploy and run their own operating systems and applications. IT has control only over operating systems and applications. IT can configure storage and some network configurations. IaaS is used to create platforms for service and application development, test, and deployment.
2. Platform as a Service (PaaS) provides application hosting and development tools. Developers create and deploy their applications into cloud infrastructures. Developers control only their applications and some operating system configurations. PaaS is used to create and deploy applications and services for users.
3. Software as a Service (SaaS) provides pre-built applications, typically available via web browser. Consumers control only application configuration settings. SaaS is used to complete business tasks.

Four cloud deployment models describe cloud ownership and usage.

1. Private Cloud: infrastructure dedicated to a single organization. The organization or a provider owns and operates it. It may be on– or off-premises.
2. Community Cloud: infrastructure shared by a group of organizations with similar needs. One or more of the organizations or a provider owns and operates it. It may be on– or off-premises.
3. Public Cloud: infrastructure for shared public use. It is owned, operated, and hosted by a service provider.
4. Hybrid Cloud: combines services from two or more different cloud models.

In the next post I’ll talk about what you need to do in order to decide whether or not cloud is the right option for you and how to integrate it into your business model.

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Cloud Computing and Virtualization Foundations
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