Virtualization Overview
Virtualization is a broad term. In terms of computers, computer components (hardware, software, and operating) systems, etc., are usually run on virtual basic equipment, not real equipment.
Here mainly explains virtualization in cloud computing.
As the foundation of cloud computing, virtualization technology belongs to the cloud computing technology's infrastructure as a service layer, which provides "resource integration" and "re-logic" (for example, a user sends a request, and the administrator receives the request and sends the computer that the user needs Resources are sorted into "computers" that can be put into use immediately, and then provided to users.) Allocate on demand to make full use of resources.
Why virtualize?
From a personal perspective: In the past, most individual users used computers to surf the Internet, chat, watch videos, and process documents. Few people used video or image processing applications that consume CPU or CPU resources. (Maybe someone will say, who said that now many people play computer games and computer games are also consuming a lot of CPU! We know that computers are getting faster and faster, so when we go online, chat, and process documents, we Wasted resources are far more than before.) This results in most of the time the CPU usage is less than 30% or even 10%.
From the perspective of the enterprise: At present, the physical servers used by many enterprises generally run a single operating system or a single application. As the performance of the server is greatly improved, the use efficiency of the server is getting lower and lower. According to the survey, most enterprise servers are simply Web servers, database servers, or FTP servers. The CPU usage of these servers is less than 20% for a long time, the memory usage is less than 30%, and the hard disk usage is less than 10%.
Based on the above situation, the low utilization rate of computer resources is a problem that the entire IT industry is facing. On this basis, virtual machines and virtualization technologies have emerged.
How virtualization works
Virtualization works by inserting a streamlined software layer directly on the physical server hardware or on the host operating system. This software layer contains a virtual machine monitor (virtualization hypervisor, which also Hypervisor). I believe many people have learned the object-oriented programming language, understand the principle of "encapsulation", and take Java as an example to encapsulate specific properties and methods into a class. The working principle of virtualization also includes a similar "encapsulation process", which "encapsulates" hardware resources (including CPU, memory, operating system, and network devices), so virtual machines can work with all standard operating systems, applications, and devices The driver is fully compatible with multiple operating systems and applications that can be installed and run on one physical server at the same time, and each operating system and application can access its required resources when it is needed.
Virtual machine (VM)
"Virtual machine (VM)" is a virtual computer system, which is a tightly isolated software container that contains an operating system and applications. Each fully functional virtual machine is completely independent, including its own independent (that is, software-based) CPU, memory, hard disk, graphics card, sound card, and network card.
The completed virtual machine is different from the "physical" computer to the "virtual" computer. For the operating system running in the computer, they are equivalent, and cannot distinguish between physical and virtual machines. In short, virtual machines are basically no different from physical machines for the operating systems and applications that run on them.
By placing multiple virtual machines that have been set up on one computer, multiple operating systems and applications can be run on one physical server or "host".
Advantages of virtualization
1. Virtualization is a process that breaks the hard connection between physical hardware and the operating system and the applications running on it.
2. Virtualization has a wide range of applications and can be applied to computers, operating systems, storage devices, applications or networks.
3. Under the virtualization platform, the server resources are integrated, which greatly improves the utilization rate of the resources. At the same time, the virtualization platform itself provides convenience in fault recovery, business deployment, migration, conversion, update, and maintenance, reducing IT costs. And improve the use efficiency and flexibility.
After years of development, virtualization technology has become a proven technology, which can save computer resources and reduce IT costs while greatly improving IT efficiency and agility. Virtualization is changing the IT landscape and fundamentally changing the way people use technology
