Cloud Computing Definition
If you’ve read about Cloud Computing for any length of time, you’ve no doubt stumbled across a wide range of Cloud definitions.
The most important thing to realise is that “cloud” is not a technology, but an *operational model.
There is no “industry standard” definition yet for what a Cloud is or isn’t. However, there is growing acceptance of a definition put together by the US National Institute of Standards and Technology (NIST). This defintion, in its 15th version as of writing, considers cloud characteristics, service and deployment models.
The following is an extract:
Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model promotes availability and is composed of five essential characteristics, three service models, and four deployment models.
- On-demand self-service
- Broad network access
- Resource pooling
- Rapid elasticity
- Measured Service
Service models include:
- Cloud Software as a Service (SaaS)
- Cloud Platform as a Service (PaaS)
- Cloud Infrastructure as a Service (IaaS)
- Private cloud. The cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on premise or off premise.
- Community cloud. The cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on premise or off premise.
- Public cloud. The cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.
- Hybrid cloud. The cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds).