What is Hypervisor? Advantages and usage of Hypervisor

What is Hypervisor? Advantages and usage of Hypervisor

According to Wikipedia:"HypervisorOrVirtual machine monitor (VMM)Is the software, firmware, or hardware that creates and runs virtual machines ".

In general,Hypervisor is a method of separating the operating system from the hardware abstraction.To enable the host machine hardware to run at most one virtual machine at the same time as the guest machine, so that these virtual machines can efficiently share host hardware resources.

Hypervisor has the following advantages:

Improve host hardware usage efficiency. Because a host can run multiple virtual machines, the hardware resources of the host can be fully utilized.Strong Virtual Machine mobility. Traditional software is strongly bound to hardware, and transferring one software to another is time-consuming (such as re-installation). However, virtual machines and hardware are independent, in this way, the virtual machine can be transferred at low consumption on the local or remote virtual server.Virtual machines are independent of each other. The crash of one virtual machine does not affect other virtual machines that share the same hardware resources, greatly improving security.Easy to protect and recover. Snapshot technology can record the status of virtual machines at a certain time point, which enables rapid recovery of virtual machines after an error occurs. Hypervisor type:

Bare-metal hypervisors: Directly deployed on the host hardware to manage the hardware and guest machine.Hosted hypervisors: The software layer is deployed on the host operating system. Currently, VMware Player and VirtualBox are commonly used.

Type I: Local or bare-metal Hypervisor

First-class virtual machines

These virtual machine management programs run directly on the host hardware to control the hardware and manage the object operating system.

Features require hardware support for Virtual machine monitors as the main operating system for high operating efficiency examples VMware5.5 and later versions of Xen3.0 and later versions of Virtual PC 2005KVM

Type II: Hosted Hypervisor

These virtual machine management programs run on traditional operating systems, just like other computer programs.

Features Virtual machine monitors run as applications in the main operating system environment efficiency is generally lower than type I Examples of VMware5.5 versions earlier than Xen3.0 version of Virtual PC 2004