What is cloud computing? What are the definition, characteristics, and models of cloud computing?

1. Introduction to Cloud Computing

1. What is cloud computing?

To put it simply, cloud computing is to put all resources in a unified resource pool through pooling, and then provide this resource pool in the form of a network, and then users can use the network to rent and charge by volume. To get the resources in this huge resource pool

2. Cloud computing resources

• Internet resources
• Storage resources
• Computing resources
  ...

3. The definition of cloud computing

• Cloud computing is a model that can easily access a public set of configurable computing resources (for example, networks, servers, storage devices, applications, and services) on demand.
• These resources can be quickly provided and released, while minimizing management costs or service provider intervention.
• The cloud model consists of five basic characteristics, three service models, and four publishing models, which makes the above possible.

3.1 Five basic characteristics

3.1.1 On-demand self-service

• Depending on the needs of customers, each service provider can unilaterally provide customers with computing power, such as server time and network storage, and these are automatically performed without intervention

3.1.2 Extensive network access

• With the ability to access the network through a standardized mechanism, this mechanism can use a variety of thin and fat client platforms (for example, mobile phones, laptops, and PDAs)

3.1.3 Resource Sharing

• The computing resources provided by the provider are concentrated to provide services to multiple customers through a multi-customer sharing model, and different physical and virtual resources are dynamically allocated or reallocated according to the needs of the customers. There is a concept of regional independence, that is, customers usually do not need to control or need to know the exact location of the provided resource, but may specify the location of the resource at a higher level of abstraction (for example, country, state, or data center) . Examples of resources include storage devices, data processing, memory, network bandwidth, virtual machines, etc.

3.1.4 Fast scalability

• It has the ability to provide services quickly and scalable. In some scenarios, the provided services can be automatically and quickly expanded horizontally, quickly released under certain conditions, and quickly contracted horizontally. For customers, this ability is used to make the provided services look like unlimited, and they can purchase any quantity at any time

3.1.5 Measurable services

• The cloud system automatically controls and optimizes resources at certain abstract layers through a measurable leverage of capabilities to achieve a certain type of service (for example, storage, processing, bandwidth, and active user accounts). The use of resources can be monitored and controlled, and transparency can be achieved by providing reports of these used services to suppliers and users

3.2 Three service models

3.2.1 Software as a Service (SaaS)

• These applications provided by service providers used by customers run on cloud infrastructure. These applications can be accessed through a variety of client devices, through a client interface like a WEB browser (for example, WEB-based email). Customers do not manage or control the underlying cloud infrastructure, including networks, servers, operating systems, storage devices, and even independent application functions. Under possible abnormal conditions, limit user-configurable application settings

3.2.2 Platform as a Service (PaaS)

• Customers use development languages ​​and tools supported by cloud vendors to develop applications and publish them on the cloud infrastructure. The customer does not manage or control the underlying cloud infrastructure, including networks, servers, operating systems, or storage devices, but can control the release of applications and possible application operating environment configurations

3.2.3 Architecture as a Service (IaaS)

• Provide customers with processing, storage, network, and other basic computing resources on which customers can run any software, including operating systems and applications. The user does not manage or control the underlying cloud infrastructure, but can control the operating system, storage, publishing applications, and possibly limited control of selected network components (for example, firewalls)

3.3 Four release models

3.3.1 Private cloud (use billing)

• The cloud infrastructure is operated independently by an organization, may be managed by this organization or a third-party organization, and may exist under certain conditions or unconditionally.

3.3.2 Community Cloud

• The cloud infrastructure is shared by several organizations and supports a special community that shares concepts (for example, tasks, security requirements, strategies, and appropriate decisions) with each other. It may be managed by these organizations or third-party agencies, and may exist under certain conditions or unconditionally.

3.3.3 Public Cloud

• The cloud infrastructure is made into general public or used by a large industrial group, owned by an organization, and sold cloud services.

3.3.4 Hybrid cloud (public cloud, private cloud)

• The cloud infrastructure is composed of two or more clouds. These clouds maintain a single entity but are combined through standard or unique technologies. These technologies make data or applications portable. (For example, Cloud Bursting technology for load balancing between clouds) (Hardware resource overload)

4. Cloud computing service model

1. IaaS (Infrastructure as a Service) provides the underlying hardware resources and environment

• Provide underlying IT infrastructure services, including processing capacity, storage space, network resources, etc.
• Object-oriented is generally IT managers

2. PaaS (Platform as a Service)

• Provide the system platform with the installed development environment as a service to users via the Internet
• Object-oriented is generally developers, software engineers

3. SaaS (software as a service)

• Provide users with services such as software and applications directly through the Internet
• Object-oriented is generally a normal user

Two, summary

Essentially, the purpose of cloud computing is to separate all the heavy work involved in processing data from its own equipment and transfer it to large computer clusters far away in cyberspace. The Internet becomes the cloud, and then users can obtain the data, work and applications they want from the resource pool through the form of network lease and pay-as-you-go billing.