Riportiamo di seguito la definizione di Cloud Computing del NIST (National Institute of Standards and Technology)
The NIST Definition of Cloud Computing
Authors: Peter Mell and Timothy Grance
Special Publication 800-145 (Draft) – January 2011
Recommendations of the National Institute of Standards and Technology
Autority : The National Institute of Standards and Technology (NIST) developed this document in furtherance of its statutory responsibilities under the Federal Information Security Management Act (FISMA) of 2002,Public Law 107-347.NIST is responsible for developing standards and guidelines, including minimum requirements, for providing adequate information security for all agency operations and assets; but such standards and guidelines shall not apply to national security systems. This guideline is consistent with the requirements of the Office of Management and Budget (OMB) Circular A-130, Section 8b(3), “Securing Agency Information Systems,” as analyzed in A-130, Appendix IV: Analysis of Key Sections. Supplemental information is provided in A-130, Appendix III.This guideline has been prepared for use by Federal agencies. It may be used by nongovernmental organizations on a voluntary basis and is not subject to copyright, though attribution is desired.Nothing in this document should be taken to contradict standards and guidelines made mandatory and binding on Federal agencies by the Secretary of Commerce under statutory authority, nor should these guidelines be interpreted as altering or superseding the
Purpose and Scope : The purpose of this publication is to provide the NIST definition of cloud computing. NIST intends this informal definition to enhance and inform the public debate on cloud computing.Cloud computing is still an evolving paradigm. Its definition, use cases, underlying technologies,issues, risks, and benefits will be refined and better understood with a spirited debate by the public and private sectors. This definition, its attributes, characteristics, and underlying rationale will evolve over time.
Audience : The intended audience is people adopting the cloud computing model or providing cloud services.
Definition of Cloud Computing:
Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) thatcan 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 servicemodels, and four deployment models.
On-demand self-service. A consumer can unilaterally provision computing capabilities, such asserver time and network storage, as needed automatically without requiring human interaction with each service’s provider.
Broad network access. Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g.,mobile phones, laptops, and PDAs).
Resource pooling. The provider’s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level ofabstraction (e.g., country, state, or datacenter). Examples of resources include storage,processing, memory, network bandwidth, and virtual machines.
Rapid elasticity. Capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out, and rapidly released to quickly scale in. To theconsumer, the capabilities available for provisioning often appear to be unlimited and canbe purchased in any quantity at any time.
Measured Service. Cloud systems automatically control and optimize resource use by leveraging a metering capability¹ at some level of abstraction appropriate to the type of service (e.g.,storage, processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.
¹ Typically through a pay-per-use business model.
Cloud Software as a Service (SaaS). The capability provided to the consumer is to use the provider’s applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g.,web-based email). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.
Cloud Platform as a Service (PaaS). The capability provided to the consumer is to deploy ontothe cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers,operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations.
Cloud Infrastructure as a Service (IaaS). The capability provided to the consumer is to provisionprocessing, storage, networks, and other fundamental computing resources where theconsumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls).
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 aspecific community that has shared concerns (e.g., mission, security requirements, policy,and compliance considerations). It may be managed by the organizations or a third partyand may exist on premise or off premise.
Public cloud. The cloud infrastructure is made available to the general public or a large industrygroup 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., cloudbursting for load balancing between clouds).