I. Overview
The concept of cloud computing (cloud computing) was born in 2007. After more than half a year, it has received more attention than grid computing (Grid Computing), and the attention has remained high until now. Cloud computing includes the application of various service forms on the Internet, as well as the software and hardware facilities of the data center on which these services are based.
Cloud (cloud) represents the Internet (Internet). We store data in servers on the network through the network services we use, browse the web pages of these services through browsers, and use the above interface to perform various calculations and work. .
Cloud computing is a utility-oriented and Internet-centric way of delivering IT services on demand. These services span the entire computing stack: from packaged hardware infrastructure as a series of virtual machines, to software services such as development platforms and distributed applications. It can dynamically provision and present computing resources as one or more uniform computing resources based on established service-level agreements through service negotiation between suppliers and customers.
2. Key technologies
Public Cloud: A model based on standard cloud computing in which service providers create resources, such as applications, computing, and storage, and make them available over the Internet. Basic features: multi-tenant, real-time monitoring of cloud resources, on-demand development scale and high load maintenance. Amazon EC2 is a public cloud that provides infrastructure as a service, Google AppEngine is a public cloud that provides an application development platform as a service, and Salesforce.com is a public cloud that provides soft infrastructure as a service. A public cloud can consist of geographically dispersed data centers in order to share user load and serve users better based on their location. For example, Amazon Web Services' data centers are distributed in the United States and Europe, allowing their customers to choose among three regions.
Private Cloud: A private cloud is built for the sole use of one customer, thus providing the most effective control over data, security and quality of service. They can be deployed inside the firewall of the enterprise data center, or they can be deployed in a secure hosting place, with the advantages of protecting customer information SLA (quality of service), making full use of existing hardware resources and software resources, and complying with standard procedures and operations.
Software as a Service (SaaS): It runs in the cloud and is provided to users as a service. The proposal of SaaS was prior to cloud computing and began to circulate in the late 1990s. The abbreviation of SaaS was created and defined by the Software Information Industry Association in 2001. With the advent of cloud computing there has been increasing acceptance of SaaS as a viable software delivery model.
Platform as a Service PaaS: supports the application infrastructure and provides services. Provides a development and deployment platform for applications. They constitute middleware on top of which users can build applications. Developers design their application systems based on it, regardless of hardware (physical or virtual), operating system, and other low-level services. The development model determines the interface for developing applications for users.
Infrastructure as a Service IaaS: Provide IT resource services. Provide users with a service-oriented infrastructure based on pay-as-you-go and on-demand computing models (exactly the same services as utility services such as electricity, water, and gas). The main technical solution is hardware virtualization, where one or more virtual machines are appropriately configured on a distributed system, and the associated applications are installed and deployed on the virtual machines. Virtual machines are used to virtualize hardware according to customer requirements, which reduces management and maintenance costs from the customer's point of view.
SOA construction layer: encapsulates cloud computing capabilities, becomes a standard web service, and incorporates into the SOA system.
Management middleware layer: resource management and task scheduling, so that resources can provide services for applications efficiently and safely.
Resource pool layer: A large number of resources of the same type form an isomorphic or nearly isomorphic resource pool.
Physical resource layer: computers, storage, network facilities, databases and software, etc.