云计算的四个服务层次(云计算的三大服务模式为)

Customer-level services.
What does not belong to the cloud computing service layer is customer-level services. The entire cloud computing service collection is divided into 4 levels: application layer, platform layer, infrastructure layer and virtualization layer.
Cloud computing is a type of distributed computing, which refers to the decomposition of huge data computing processing programs into countless small programs through the network "cloud", and then processing and processing through a system composed of multiple servers. Analyze these applets to get results and return them to the user.

Cloud computing is mainly divided into four categories: public cloud, private cloud, community cloud and hybrid cloud.

Public cloud uses the Internet to provide cloud computing services to the public; private cloud uses corporate intranets and private networks to provide cloud computing services to a single enterprise or organization. These services are not available to the public. ; Community cloud uses intranet, private network and VPN to provide cloud computing services for multiple related departments; hybrid cloud is a combination of the above two or three clouds.

In layman’s terms, cloud computing turns computing into an infrastructure like water, electricity, and gas. People can purchase computing services just like water, electricity, and gas. It can be said that cloud computing has redefined It has changed the way IT software and hardware resources are designed and purchased, which may trigger large-scale changes in the IT industry.

Introduction to cloud computing:

Cloud computing is a type of distributed computing, which refers to the transfer of huge data through the network "cloud" The calculation processing program is decomposed into countless small programs, and then, these small programs are processed and analyzed through a system composed of multiple servers to obtain results and return to the user.

In the early days of cloud computing, to put it simply, it was simple distributed computing, solving task distribution and merging calculation results. Therefore, cloud computing is also called grid computing. Through this technology, tens of thousands of data can be processed in a very short time (a few seconds), thereby achieving powerful network services.

The architecture of cloud computing includes: application layer, platform layer, infrastructure layer and data center layer.

1. Application layer:

The application layer is the top-level cloud computing service layer, which includes application services in various fields. Services at this layer are user-facing and are usually provided through a web interface or API.

2. Platform layer:

The platform layer provides operating systems and software environments that support cloud computing, including various development languages ​​and tools, such as Java, Python, and Ruby. wait. Services in this layer are designed for developers and business users, who can freely combine these software to customize their own solutions.

3. Infrastructure layer:

The infrastructure layer provides the physical and virtual equipment required for cloud computing services, including servers and storage Equipment, network equipment, etc. Services at this layer are for IT professionals and business users, who can access these resources through APIs to meet business needs.

4. Data center layer:

The data center layer mainly includes the physical data center and virtualization software architecture. These include device management, network management, security and monitoring functions. The services at this layer are for item managers and IT operation and maintenance personnel. They can access these resources through APIs to ensure the high availability and reliability of the business system.

5. Public cloud, private cloud and hybrid cloud:

According to the usage scope and management method of cloud computing services, it can be divided into public cloud, private cloud and hybrid cloud. Three types of clouds. Public clouds are operated and maintained by third-party service providers and can be shared by multiple customers, such as AWS, Azure, and Alibaba Cloud.

Private cloud is managed and used by a single organization or enterprise alone, so it is more secure and private, but its cost is also higher; hybrid cloud is a combination of public cloud and private cloud, which can Allow enterprises to scale up with cheaper public cloud resources without losing confidential information.

6. Cloud computing service model:

According to business needs, cloud computing can be further divided into three different service models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS).

IaaS provides infrastructure leasing and third-party hosting services, such as servers, storage, networks, etc., PaaS provides operating environments and development tools, such as operating systems, databases, and web servers, and SaaS provides Including application software directly facing users, such as email services, CRM systems, collaboration tools, etc.

7. Cloud computing technology:

Cloud computing technology includes virtualization technology, automated deployment technology, container technology and other technical means, among which virtualization technology is One of the core technologies of cloud computing architecture. Through virtualization technology, physical devices can be abstracted and several virtual devices can be merged into one logical device, thereby improving the utilization and flexibility of physical resources and reducing the complexity and cost of resource management.

8. Cloud computing development trends:

With the continuous development of cloud computing technology, cloud computing architecture is also constantly updated and optimized. The future cloud computing platform will be more intelligent, automated and secure, and there will be more application scenarios and service models, such as mobile cloud computing, distributed cloud computing, blockchain cloud computing, etc., which will greatly expand the scope of cloud computing. potential and prospects.

The architecture of cloud computing so far can be mainly divided into four layers.
First: the display layer. This layer of multi-data center cloud computing architecture is mainly used to use friendly way to display the content required by users, and will make use of the various services provided by the middleware layer below. There are five main technologies:
HTML: standard Web page technology, currently mainly HTML4, but will be The launch of HTML5 will promote the development of Web pages in many aspects, such as video [1] and local storage.
JavaScript: A dynamic language used for Web pages. Through JavaScript, the functions of Web pages can be greatly enriched.
CSS: Mainly used to control the appearance of Web pages, and to elegantly separate the content of the page from its presentation.
Flash[2]: The most commonly used RIA (Rich Internet Applications) technology in the industry can provide Web-based rich applications that HTML and other technologies cannot provide at this stage, and it is very good in terms of user experience[3].
Silverlight: RIA technology from the industry giant Microsoft[4]. Although its current market share is slightly lower than Flash, it is very friendly to developers because it can be programmed using C#[5].
Secondly: The middle layer is a link between the previous and the following. It provides a variety of services based on the resources provided by the infrastructure layer below, such as cache services and REST services, and these services can be used to support the display layer. , can also be called directly by users, and there are mainly five technologies;
REST: Through REST technology, some services supported by the middleware layer can be provided to the caller very conveniently and elegantly.
Multi-tenancy: It allows a single application instance to serve multiple organizations while maintaining good isolation and security. Through this technology, it can effectively reduce the cost of application acquisition and Maintenance costs.
Parallel processing: In order to process massive amounts of data, it is necessary to use a huge X86 cluster for large-scale parallel processing. Google's MapReduce is a representative work in this regard.
Application server: Based on the original application server, a certain degree of optimization has been made for cloud computing, such as the Jetty application server for Google AppEngine.
Distributed caching: Through distributed caching technology, it can not only effectively reduce the pressure on the backend server, but also speed up the corresponding response. The most famous example of distributed caching is Memcached.
Furthermore: The role of the infrastructure layer is to prepare the computing and storage resources required by the upper middleware layer or users. There are four main technologies:
Virtualization : It can also be understood as "multi-tenancy" at 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 not only Reduce server purchase costs, and also reduce server operation and maintenance costs. Mature X86 virtualization technologies include VMware's ESX and open source Xen.
Distributed storage: In order to carry massive amounts of data while ensuring the manageability of these data, a complete set of distributed storage systems is required.
Relational database: Basically, it is based on the original relational database and has been optimized in terms of expansion and management to make it more adaptable in the cloud.
NoSQL: In order to meet some goals that cannot be met by relational databases, such as supporting massive amounts of data, some companies specially design a batch of databases that are not based on relational models.
Finally: The management layer serves the three horizontal layers and provides these three layers with a variety of management and maintenance technologies, mainly including the following six aspects:

Account management: Through good account management technology, users can log in conveniently under safe conditions, and administrators can manage accounts conveniently.
SLA monitoring: Monitor the performance of virtual machines, services and applications running at all levels, so that they can all run while meeting the preset SLA (ServiceLevelAgreement).
Billing management: that is, counting the resources consumed by each user to accurately charge users.
Security management: Comprehensive protection of IT[6] resources such as data, applications and accounts to protect them from criminals and malicious programs[7].
Load balancing: Respond to emergencies by distributing traffic to multiple instances of an application or service.
Operation and maintenance management: The main purpose is to make the operation and maintenance operations as professional and automated as possible, thereby reducing the operation and maintenance costs of the cloud computing center.
There are three horizontal layers in the cloud computing architecture, namely the display layer, the middleware layer and the infrastructure layer. Through these three layers of technology, it can provide very rich cloud computing capabilities and friendly user interfaces. The cloud computing architecture also There is a vertical layer, called the management layer, which exists to better manage and maintain the three horizontal layers.