Generally speaking, the generally recognized cloud architecture is divided into three levels: infrastructure layer, platform layer, and software service layer. The corresponding names are IaaS, PaaS and SaaS
Related reading: Video cloud service industry development trend: PaaS
what is the SaaS model
Cloud computing structure
(system architecture diagram of cloud computing virtual machine architecture)
SaaS display layer
Saas, software as a service, users only need to pay a certain rental fee to enjoy the corresponding services through the Internet, and the maintenance of the entire system is also the responsibility of the manufacturer, without having to purchase software and hardware, build a computer room, and provide maintenance personnel. This layer of most data center cloud computing architecture is mainly used to present the content and service experience required by users in a friendly way, and will utilize the various services provided by the following middleware layers, mainly including five technologies:
1. HTML: Standard Web page technology, mainly HTML4, but the upcoming HTML5 will promote the development of Web pages in many aspects, such as video and local storage.
2. JavaScript: A dynamic language for web pages. Through JavaScript, it can greatly enrich the functions of web pages, and use JavaScript-based AJAX to create more interactive dynamic pages.
3. CSS: Mainly used to control the appearance of the Web page, and can make the content of the page and its manifestation be separated elegantly.
4. Flash: RIA (Rich Internet Applications), the most commonly used technology in the industry, can provide rich Web-based applications that HTML and other technologies cannot provide at this stage, and it is very good in terms of user experience.
5. Silverlight: RIA technology from industry giant Microsoft, although its market share is slightly lower than Flash, but because it can use C# for programming, it is very friendly to developers.
PaaS middle layer
The PaaS middle layer, also known as the platform layer, takes the software development environment as a service to provide users. The platform layer is mainly designed for application developers, facing the majority of Internet application developers, to develop, test, deploy, and run distributed software. The environment and complex application hosting as a service allows developers to free themselves from complex and inefficient environment construction, configuration, and maintenance, and focus on software writing, thereby greatly improving the efficiency of software development. The platform layer is The core layer of the entire cloud computing system, including parallel programming and development environment. This layer is a link between the previous and the next. It provides a variety of services on the basis of the resources provided by the underlying infrastructure layer, such as caching services and REST services, and these services can be used to support the display layer or be directly called by users. And there are mainly five technologies:
1. REST: Through REST technology, part of the services supported by the middleware layer can be provided to the caller very conveniently and elegantly.
2. Multi-tenancy: It is to enable a single application instance to serve multiple organizations, and maintain good isolation and security, and through this technology, it can effectively reduce the cost of application acquisition and maintenance.
3. Parallel processing: In order to process massive amounts of data, a huge X86 cluster needs to be used for massive parallel processing. Google's MapReduce is a representative work in this regard.
4. Application server: On the basis of the original application server, a certain degree of optimization has been made for cloud computing, such as the Jetty application server for Google App Engine.
5. Distributed cache: Distributed cache technology can not only effectively reduce the pressure on the background server, but also speed up the corresponding response speed. The most famous example of distributed cache is Memcached.
Pan-entertainment and online education are two major application scenarios that PaaS vendors are generally optimistic about, such as online live broadcasting, enterprise live broadcasting, distance education, dual-teacher classrooms, and video conferences.
IaaS infrastructure layer
The Iaas infrastructure layer is also called the resource layer. The role of this layer is to prepare the computing and storage resources required by the upper middleware layer or users, such as servers, network equipment, storage devices, etc., to combine these physical Equipment, through the virtualization layer adopts corresponding technology to form a dynamic resource pool, there are mainly four technologies:
1. Virtualization: It can also be understood as the "multi-tenant" of the infrastructure layer, because through virtualization technology, multiple virtual machines can be generated on a physical server, and comprehensive isolation can be achieved between these virtual machines , This can not only reduce the purchase cost of the server, but also reduce the operation and maintenance cost of the server at the same time. Mature X86 virtualization technologies include VMware ESX and open source Xen.
2. Distributed storage: In order to carry massive amounts of data and at the same time ensure the manageability of these data, a complete set of distributed storage systems are needed.
3. Relational database: It is basically optimized in terms of expansion and management based on the original relational database to make it more adaptable in the cloud.
4. NoSQL: In order to meet the goals that some relational databases cannot meet, such as supporting massive amounts of data, some companies specially design a batch of databases that are not based on relational models.
The characteristics and advantages of cloud architecture: easy to expand functions, easy to expand performance, high resource utilization, fast resource recovery, low interaction delay, extensive basic communication interoperability, detailed analysis of advantages, disadvantages and characteristics can be read: https:// www.yealink.com.cn/information/395