What is Hypervisor?
A Hypervisor also known as Virtual Machine Monitor (VMM) can be a piece of software, firmware or hardware that gives an impression to the guest machines(virtual machines) as if they were operating on a physical hardware. It allows multiple operating system to share a single host and its hardware. The hypervisor manages requests by virtual machines to access to the hardware resources (RAM, CPU, NIC etc) acting as an independent machine.
Now the Hypervisor is mainly divided into two types namely
Type 1/Native/Bare Metal Hypervisor
Type 2/Hosted Hypervisor
Let us try to understand about them in detail
Type 1 Hypervisor
- This is also known as Bare Metal or Embedded or Native Hypervisor.
- It works directly on the hardware of the host and can monitor operating systems that run above the hypervisor.
- It is completely independent from the Operating System.
- The hypervisor is small as its main task is sharing and managing hardware resources between different operating systems.
- A major advantage is that any problems in one virtual machine or guest operating system do not affect the other guest operating systems running on the hypervisor.
VMware ESXi Server
Type 2 Hypervisor
- This is also known as Hosted Hypervisor.
- In this case, the hypervisor is installed on an operating system and then supports other operating systems above it.
- It is completely dependent on host Operating System for its operations
- While having a base operating system allows better specification of policies, any problems in the base operating system a ffects the entire system as well even if the hypervisor running above the base OS is secure.
Microsoft Virtual PC
Oracle Virtual Box