The popular saying "cloud computing" (turn)

"Cloud" is a service, how abstract it is. Don't worry. Here are the popular.
Before talking about cloud computing, you should talk about clusters first. The application of the cluster has been for many years, I just say it briefly. Clustering provides a way to make multiple server systems virtual as a system, and for programmers, running a program on a cluster is like making no difference to a single server. This cluster has done a lot of work for us, such as file management, load balancing, even session management. It links multiple machines together in a clustered way.

And cloud computing is based on the technology of the cluster changes. Cloud computing is based on cluster technology, integrating a large number of servers (or even hundreds of thousands of). These hardware resources are then managed on demand and then provided to customers with a number of services (Laas+paas+saas ...). ）。 Here's what to say. Cluster has a disadvantage, the cluster of resources in each node can not be dynamically allocated, such as a request to the load balanced forward to the a server, but did not think that this request is a 10 million records hundreds of times the total operation. Clatter may be fatal. So how to solve this problem. The answer is LAAS (infrastructure is service). This problem is finally resolved: software to the cluster of all servers in the CPU, memory, disk and other key hardware resources for dynamic management. When a request requires a large amount of hardware resources, the metadata that needs to be computed is sent to multiple hardware entities to run in parallel (or, of course, a copy of the data on multiple servers, which can even be a large number of copies, which can also play a backup role), So that each server's hardware resources can be fully played. (as a technician, immediately think, 1G of data transmission between the network reality.) This is true, as Hadoop did, and it was an Open-source project developed by Apache based on Google's file system. There are already some big software companies with some cloud operating system technology, Microsoft: Azure. Ubuntu has a version of the corporate cloud. Of course, we also need to solve a lot of other problems, such as: Security, performance, compatibility and so on. In short, cloud computing is a development from cluster technology, the difference is that, although the cluster has multiple machines, the execution of a specific task will be forwarded to a server, and the cloud can simply assume that the task can be split into multiple processes on multiple servers in parallel computing. And then get the results, the advantage is that the large amount of data operation performance is very good. You can use a cheap PC server to manage large volumes of data and large clusters. The key technology is to be able to dynamically allocate and manage the infrastructure in the cloud.

With the above technology, people find that he has brought us a revolution. A change in the business model, since our hardware resources can be dynamically on demand, then we can deploy the software we developed directly in our cloud, and then directly through the Internet to provide users with services, so even if a large number of concurrent users can also protect their performance. For example, Google has word online. There are also Baidu in China. Wait a minute. This will be an important change in the business model of the software industry in the next period. This is SaaS: Software is a service.

Software development has always been a product and custom development of two categories. Just said in the cloud release software, directly to provide users with services equivalent to products. Custom development. We can put our workflow, ERP and so on in the cloud, directly to the entire development platform in a service way to provide users, this is PAAs: platform is the service.
This is the initial application of cloud computing, so the text said: "Cloud" is the service.

Personal feeling, cloud computing in China will face several problems:

1, the popularity of the popular concept of cloud computing. Know that the vast majority of decision makers are unprofessional, even if they want to know what cloud computing is. Cloud computing is a large cluster + service. The so-called service refers to: The dynamic allocation of hardware resources and infrastructure. And then some of the services are by yourself to play, you can provide users with online software and so on.

2, security issues. When people understand that cloud computing is a server that is busy and can send data to other servers for parallel computing, people will think their data is unsafe. We can solve some of the problems with some security measures, if the data itself is a need for high security, such as government departments, then we can use the establishment of private cloud to solve this problem.
3, the cloud is also "data services." A lot of people on the Internet are talking about Laas, SaaS, PAAs, but few people mention "data Services" we can call it "Daas" (data as a server) as a service. We can provide data services to outside users through cloud computing.
In short, "cloud" is the use of some of the existing technology, in the implementation of the dynamic infrastructure allocation, to provide users with a service technology, a business model ...

This is my understanding of cloud computing. I hope I can help you understand cloud computing through this popular explanation.