What is cloud computing?
The National Institute of Standards and Technology (NIST) defines cloud computing as: "A model for enabling convenient, on-demand access to a shared pool of configuration computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction." Our definitions for the 5 essential characteristics of cloud computing defined by NIST are:
- On-demand self-service: The consumer alone can request computing resources which are automatically provisioned without any human interaction
- Broad network access: APIs and management tools are provided by the vendor allowing computing resources to be requested over the Internet
- Resource pooling: Computing resources are pooled to service multiple consumers using a multi-tenant model, with resources dynamically assigned according to consumer demand
- Rapid elasticity: To the customer, compute capabilities appear unlimited and can be rapidly and elastically provisioned both scaling up and back down per customer need
- Measured service: Use of compute resources is monitored and tracked by the provider. Customers are billed based on a utility consumption model. There are no setup fees or contracts
http://csrc.nist.gov/groups/SNS/cloud-computing/