Introduction
A hypervisor is virtualization software that divides and allocates resources to various pieces of hardware in Cloud hosting. A virtualization hypervisor is a program that allows segmentation, isolation, or abstraction. The hypervisor is a hardware virtualization method that enables many guest operating systems (OS) to run simultaneously on a single host system. It is also called virtual machine manager (VMM).
The term "guest machine" refers to a virtual machine. The hypervisor enables various guest machines to run on the actual host machine. It allows you to get the most out of computational resources, including memory, network bandwidth, and CPU cycles.
Types of Hypervisors
There are two types of hypervisors.
Type I Hypervisor
A Type I hypervisor, often referred to as bare metal, monitors the hardware and guest virtual machines directly on the host's hardware. They usually do not require any prior software installation. A Type 1 hypervisor is most commonly used by cloud providers, in which virtualization software is installed directly on the hardware.
Examples of Type I hypervisors include Oracle VM Server for Xen, Oracle VM Server for x86, Microsoft Hyper-V, and VMware's ESX/ESXi.
Pros and Cons of Type I Hypervisor
Pros: Because they have direct access to physical hardware, Type 1 hypervisors are highly efficient. This also improves their security because there is nothing in the way of an attacker gaining access to the CPU.
Cons: A Type 1 hypervisor often needs a separate management machine to administer different VMs and control the host hardware.
Type II Hypervisor
A Type II hypervisor does not run on the physical hardware. Instead, it runs as an application on an operating system. Type 2 hypervisors are uncommon in a server-based environment. Instead, they're designed for single-user PCs that need to run multiple operating systems. Engineers and security professionals use type II hypervisor to analyze malware and business users who require access to applications only on other software platforms.
Users can often install additional toolkits into the guest OS with Type 2 hypervisors; these tools improve the connection between the guest and the host OS, allowing users to cut and paste between the two or access files and folders on the host OS from within the guest VM.
Pros and Cons of Type II Hypervisor
Pros: A Type II hypervisor allows for quick and easy access to a secondary guest OS in addition to the primary host system. And because of this, it is excellent for end-user productivity. For example, a consumer could use it to access their favorite Linux-based development tools while using a Windows-only speech dictation system.
Cons: A Type II hypervisor must use the host OS, which has direct access to the physical machine, to access computing, memory, and network resources. This causes latency issues, which has an impact on performance. If the host OS is compromised, an attacker can manipulate any guest OS running in the Type 2 hypervisor, posing a security risk.