1. Concept of Cloud Computing
1.1 NIST Draft Definition of Cloud Computing
The experts of the National Institute of Standards (NIST) gave a draft definition of cloud computing on April 24, 2009, which summarizes the five major features, three major service models, and four major deployment models of cloud computing.
1.1.1 Definition of Cloud Computing
Cloud computing is a pay-per-use model that provides available, convenient, and on-demand network access to a configurable pool of computing resources*** (resources that include networks, servers, storage, applications, and services) that can be rapidly provisioned with little administrative effort or interaction with service providers. service providers with little management effort or interaction. The cloud computing model improves availability. The cloud computing model consists of five key features, three service models, and four deployment models.
1.1.2 Key Features
(1) On-demand self-service. Consumers can unilaterally deploy on-demand processing capabilities, such as server time and network storage, without manually interacting with each service provider.
(2) Access via the Web. Capabilities are available over the Internet and can be accessed in a standardized way to be rolled out to numerous thin or rich clients (e.g., cell phones, laptops, PDAs, etc.).
(3) Location-independent resource pooling. A provider's computing resources are pooled in order to serve all customers in a multi-user rental model, while different physical and virtual resources can be dynamically allocated and reallocated based on customer demand. Customers generally have no control or knowledge of the exact location of the resources. These resources include storage, processors, memory, network bandwidth, and virtual machines.
(4) Rapid scalability. Capacity can be provided quickly and elastically, can be scaled up quickly, and can be released quickly to achieve rapid shrinkage. The resources that can be rented appear to be seemingly unlimited to the customer and can be purchased in any quantity at any time.
(5) Pay-per-use. Capabilities are charged either on a metered pay-per-use basis or on an advertised fee model that promotes optimal use of resources. For example, metering the consumption of storage, bandwidth, and compute resources and charging users on a monthly basis based on their actual usage. Clouds within an organization can calculate fees between departments, but not necessarily in real currency.
Note: Cloud computing software services focus on borderlessness, low coupling, modularity, and semantic interoperability to take full advantage of the cloud computing model.
1.1.3 Service Models
(1) Cloud Computing Software as a Service. The capabilities provided to the customer are the service provider's applications running on the cloud computing infrastructure that can be accessed on a variety of client devices through a thin client interface, such as a browser. The underlying cloud computing infrastructure, network, servers, operating system, storage, and even individual application capabilities that the consumer does not need to manage or control, with the possible exception of some limited customer-customizable application software configuration settings.
(2) Cloud computing platform as a service. Provides consumers with the ability to deploy applications created by the customer using vendor-provided development languages and tools (e.g., Java, python, .Net) to a cloud computing infrastructure. The customer does not need to manage or control the underlying cloud infrastructure, network, servers, operating system, storage, but the consumer is able to control the deployed application and possibly the configuration of the application's hosting environment.
(3) Cloud Infrastructure as a Service. The capability provided to the consumer is to rent out processing power, storage, networking, and other basic computing resources, whereby the user is able to deploy and run arbitrary software, including operating systems and applications. The consumer does not manage or control the underlying cloud computing infrastructure, but is able to control the operating system, storage, deployed applications, and potentially select network components (e.g., firewalls, load balancers).
IV. Deployment Models
(1) Private Cloud. The cloud infrastructure is owned or leased by a single organization and the infrastructure is run only for that organization.
(2) Community Cloud. The infrastructure is ****enjoyed by a number of organizations and serves a community with ****identical concerns (e.g., mission, security requirements, policies and guidelines, etc.).
(3) Public **** cloud. The infrastructure is owned by an organization that sells cloud computing services to the general public or to a broad industrial community.
(4) Hybrid cloud. The infrastructure is made up of two or more clouds (internal, community, or public **** cloud), each of which remains separate but combines them with standard or proprietary technologies that have data and application portability (e.g., can be used to handle bursty loads).
1.2 The current state of the cloud computing field is characterized by the following:
(1) The major cloud computing vendors in the current market are all IT giants that are in the takedown phase.
(2) Standards have not yet been formed. On the issue of standards, basically each says its own.
Currently, there are many different cloud computing products and services on the market, and users don't know how to start when choosing.