Cloud service is an increase, use and interaction mode of related services based on the Internet, which usually involves providing dynamically expandable and often virtualized resources through the Internet. Cloud is a metaphor of network and internet. In the past, cloud was often used to represent telecommunication networks, and later it was also used to represent the abstraction of the Internet and the underlying infrastructure. Cloud service refers to obtaining the required services in an on-demand and extensible way through the network. The service can be related to IT and software, Internet or other services. It means that computing power can also be circulated as a commodity through the Internet.

Simply put, cloud service is to put all the software, hardware and data needed by enterprises on the network, and use different IT devices to connect with each other anytime and anywhere to achieve data access, calculation and other purposes. At present, there are two common cloud services: public cloud and private cloud.

The public cloud is the most basic service. Many customers can share the system resources of a service provider, and they can enjoy professional IT services without setting up any equipment or providing managers. This is undoubtedly a good way to reduce costs for ordinary entrepreneurs and small and medium-sized enterprises. Public cloud can also be subdivided into three categories, including software as a service, platform as a service and infrastructure as a service. The operation form of private cloud is similar to public cloud. However, building a private cloud is a major investment. Enterprises need to design their own data centers, networks and storage devices, and have a professional consulting team. Enterprise management must fully consider the necessity of using private cloud and whether there are enough resources to ensure the normal operation of private cloud.

There are many cloud service providers. Here are some representative ones: 1. Network science, 2. Alibaba Cloud, 3. Tencent Cloud, 4. Dilian technology, etc. Cloud services have brought convenience to many enterprises to some extent, but there are also some shortcomings. There are some security risks, on the other hand, the events caused by the offline of the cloud computing host. Therefore, the use of cloud computing is the general trend, but we should also be careful to avoid risks.