According to Wikipedia: "Hypervisor or virtual machine Monitor (VMM) is the software, firmware, or hardware that creates and runs virtual machines."
In layman's terms, hypervisor is a way of separating the operating system from the hardware abstraction, so that the hardware of host machine can run one to multiple VMS at the same time as guest machines, enabling these VMs to efficiently share host hardware resources.
Hypervisor has the following advantages:
improve the efficiency of the use of the host hardware . Because a host can run multiple virtual machines, so that the host's hardware resources can be efficiently and fully utilized. Virtual machine mobility is strong . Traditional software is strongly bundled with hardware, transferring one software to another server for time consuming (such as reinstalling), however, the virtual machine is independent from the hardware, so that the virtual machine can be transferred at a low consumption on a local or remote virtual server. virtual machines are independent of each other . The collapse of a virtual machine does not affect other virtual machines that share the same hardware resources, greatly improving security. easy to protect, easy to recover . Snapshot technology can record the state of a virtual machine under a certain point in time, which allows the virtual machine to recover quickly after an error occurs.
Types of hypervisor:
bare-metal hypervisors: Deploy directly on the host hardware to manage hardware and guest machine. hosted Hypervisors: As a software layer deployed on the host operating system, this type is now commonly used by VMware Player and VirtualBox.