Cloud computing technology is the combination of SaaS, Grid computing and virtualization

In fact. Cloud computing technology is the combination of software SaaS, Grid computing, virtualization three concepts.

Virtualization of Cloud Computing Technology (virtualization)

Virtualization is the virtualization of infrastructure (virtualization), the core of which is the combination of traditional mature cluster technology and partitioning technology. Cluster Computing (Cluster Computing) is a technology to virtual multiple servers into one server, aiming to improve computing power and improve fault tolerance and load balancing of devices. Cluster technology has been widely used in system software platform such as operating system, database and middleware. and partition computing (Partition Computing) is a mature technology on mainframe and UNIX small machines, it is to virtual a server into multiple servers, each virtual unit is called a partition, each partition is isolated, the purpose is to improve resource utilization. But now the low-end Intel Architecture PC Server also supports virtualization.

Virtualization is also currently including network virtualization (VPN) and storage virtualization (NAS) technology, together with server virtualization, built as a complete computing resources virtualized environment, under the control of the virtualization management system, the implementation of dynamic configurable intelligent system.

Grid computing (grids Computing)

Cloud computing is another manifestation of Grid computing (Computing), which is two manifestations of similar techniques.

Grid computing is a way to improve computing ability, the principle is based on the parallel computing theory, through task decomposition, the subtasks distributed to other servers to run, to obtain more powerful computing power.

Application Scenario: Scientific calculation, weather forecast, seismic analysis, geological prospecting, petroleum exploration, etc.

Task features: Re-calculation, weak flow, less interaction; This computing task consumes a lot of CPU calculation, the network traffic is small, storage and hard disk access is small.

Computing patterns: Tasks are decomposed by services, distributed computing.

Therefore, grid computing despite the efforts of IBM and other companies, the actual commercial application is not successful, mainly in some universities, scientific research institutions such as the construction of such an experimental environment, because such a calculation scenario is not common.

And cloud computing is to solve the business application environment of computing resources virtual provide more powerful computing power and resource utilization.

Application Scenarios: Enterprise Management, E-government, E-commerce, etc.

Task features: Weak computing, strong flow, multiple interaction; This application is difficult to decompose, frequent human-computer interaction, CPU consumption is not large, but storage and hard disk access, so the network traffic is also very large.

Computing patterns: Virtual resources provide more powerful computing power.
　　
The basic technology of Grid computing is Web services, broken down into services, which can be implemented in a distributed computing environment with device-independent standard interactions, and can be implemented in parallel transactions through the encapsulation of services.

The platform technology of cloud computing is mainly dependent on SOA, and we know that the main implementation technology of SOA is web Services, so the core technical basis of cloud computing and grid computing is similar.

Therefore, cloud computing business use will be very broad, can get the strong support of manufacturers and users.

The service of cloud computing

The usage pattern of cloud computing is service. The so-called service, namely the service consumer only needs to provide the service request, and submits the service the input, but does not care about the service realization method, the technology and the process, but directly obtains the service the result. The service model of cloud computing is to use Software as SaaS (Software as a service), to use the platform as a service PAAs (Platform as a services) and to IaaS the infrastructure as a service (infrastructure as a Service) and other modes.

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Software as a service Software-as-a-service, referred to as SaaS, is a completely innovative software application model that began to rise in the 21st century, with the development of Internet technology and the maturity of application software. The well-known SaaS provider Salesforce the saas  and applied to the CRM industry, a model of software delivery over the Internet, where SaaS vendors deploy applications uniformly on servers, and customers can, depending on their actual needs, Through the Internet to the service provider to order the required application software services, according to the number of services ordered and the length of time to pay the service provider, and through the Internet to obtain services provided by the provider. Users do not have to buy software, instead of renting web-based software to the provider to manage the business activities without maintaining the software, the service provider has the sole right to manage and maintain the software, and the software vendors provide Internet applications to customers while also providing off-line operation and local data storage. Allows users to use their ordered software and services anytime, anywhere. For many small businesses, SaaS is the best way to adopt advanced technology, eliminating the need for businesses to buy, build, and maintain infrastructure and applications. Software in SaaS "Software" essentially refers to the application software Application software, strictly speaking SaaS should be called AAAS (application as a  Service) or Baas (Business as a service), because the system software and platform software are not yet available as a service when SaaS occurs.

Platform is the service Platform-as-a-service, PAAs, is an important service model of cloud computing, the core of which is to provide the computing environment and the running platform of the application as a service. PAAs is implemented by encapsulating the middleware platform, its components, and the operating environment. For example, if a customer has a Java application, or a personalized application that requires an electronic map component, traditionally must purchase and configure the server hardware and operating system, as well as application Server software and electronic map components, and so on, must purchase system software such as Oracle database to provide a comprehensive computing platform, Its application software can run. Now, cloud computing can provide customers with a platform for application operation, and customers do not care about the configuration of the platform hardware environment and software systems, as long as the deployment of the platform in the PAAs or electronic map interface (WebService) can be rented to run the system.

The infrastructure, the service IaaS (infrastructure as a), is the mode of virtualization of hardware resources to provide services to customers at the operating system level, such as computing infrastructure (CPU memory and storage/operating systems), and so on, in virtual network VPNs.

The intelligence of cloud computing

Cloud computing virtualization and dynamic management is essentially a system of management intelligence, through the dynamic configuration of resource management, automatic dynamic configuration of adaptive and self-healing capabilities, cloud computing design as an intelligent system. These intelligent self-management features are:

Virtualization settings: You can easily configure virtualized computing resources on the console;
Resource dynamic configuration: It can adjust resource configuration dynamically during running period;
Automatic Monitoring system: Automatic monitoring System running health status, automatic alarm for abnormal situation;
Security isolation: The security of each virtual resource isolation, the implementation of autonomy between the instances;

Automatic load balancing: The system realizes automatic load balancing among multiple resources within a virtual device;
Resource management Decision Support: It can optimize the management decision of the cloud computing resources and realize the self optimization;
Self-recovery: cloud-computing instances and virtualized resources run into failure or deadlock, and the system has a self-healing function.
Through these intelligent management functions, cloud computing is an adaptive, self optimized intelligent system.

Conceptual model of cloud computing technology

In fact, cloud computing technology as a new technology, contains a number of layers of meaning:

The public nature of the user: cloud computing is provided by the client, both Enterprise/Government/academic/personal and other end-users, including applications, middleware platform and other "users", this is based on cloud computing to provide different levels of service.

Equipment diversity: Cloud computing services are also diverse devices, including a variety of servers, hosts, storage equipment, but also includes various types of terminal equipment, such as computers, smartphones, a variety of intelligent sensors, RFID equipment.

The service of business model: cloud computing is to provide equipment and applications in the form of services. This service feature is embodied in two aspects: Simplified and standard service interface, on-demand billing business model.

Provide flexibility: cloud computing can be used as a common facilities to provide social services, that is, "public cloud", but also as a centralized computing platform for enterprise Informatization to provide, that is, "private cloud."
　　
So the core implications of cloud computing include:

Computing service;
The virtualization of resources;
Management intelligence.