- In virtualization, the Hypervisor is also called a Virtual Machine Monitor.
- It is the low-level program that allows multiple operating system to run concurrently on a single host computer.
- Hypervisor is a piece of computer software that creates and run virtual machine.
- A computer on which a hypervisor is running one or more virtual machine is called as Host Machine.
- Each virtual machine is called a Guest Machine.
- The Hypervisor presents the guest operating system with a virtual operating platform and manage the execution of the guest operating system.
Hypevisor types -
Hypervisor have basically two types :-
1) Type 1 2) Type 2
Type 1 -
- Type 1 is also known as Native or Bore-metal.
- Type 1 hypervisor run directly on the system hardware to control hardware and manage guest operating system.
- IBM developed the original hypervisor as bare-metal tool in the 1960.
- It provide higher performance availability and security than Type 2 hypervisor.
- These are much faster than Type 2 hypervisor.
- They can directly communicate with hardware resources.
- A guest operating system runs on another level above the hypervisor. eg- Microsoft Hyoer-v.
Advantage -
- We do not have to modify the operating system and application to run the virtual environment.
- If a single virtual machine crash, it does not affect the rest of the guest operating system.
- They are more secure than Type 2.
- They generate less overhead.
- It is much faster than Type 2.
Type 2 -
- They can host different type of operating system in a single server.
- The operating system loaded into each virtual machine as a stand alone and unmodified operating system.
- When a virtual machine is running, the hypervisor make changes to the part of the operating system that makes system calls.
- Hypervisor changes the operating system by entering a piece of code which known as binary translation to the operating system when it is running.
- Binary translation takes place in 4 parts of the operating system memory, processor,network, storage that interact with the hardware. eg- VMware
Advantage -
- In Type 2, the operating system takes care of all the hardware that is why, a Type 2 hypervisor support a wide range of hardware.
- Installing a Type 2 is much easier than Type 1.