Prerequisites

What is Virtualization?

What is virtual machine?

A virtual machine (VM) is a software-based computer that exists within another computer’s operating system (OS)

• Acronym: VM
• In computing, a virtual machine is an emulation of a computer system
  • VM emulates a physical computer
  • VM is like a computer within a computer
  • VMs are virtual environments that simulate a physical compute in software form
• A VM is a computer file (typically called an image) that behaves like an actual computer
• VM runs on a host operating system and gives the end user the experience of a real computer
• VM runs on virtual hardware (CPUs, memory, hard drives etc.) provisioned by Hypervisor

Terminologies

• Host OS: The OS that runs on the actual physical machine (computer)
• Hypervisor (Hyper-V): a specialized software that allocates/virtualizes compute resources (like CPU, memory, and storage etc.)
• Guest OS: The OS that runs in a sandbox within the host OS (with help of Hyper-V)

Hypervisor

• A specialized software (part of host OS) that virtualizes hardware
• Hyper-V allows guest OS to access hardware resources
• Hypervisor is the software layer that coordinates VM

Types of hypervisors

There are 2 different types of hypervisors that can be used for virtualization:

• Type 1:
  • Bare metal
  • VM resources are scheduled directly to the hardware by the hypervisor (KVM is an example of a type 1 hypervisor)
• Type 2:
  • Hosted
  • VM resources are scheduled against a host operating system, which is then executed against the hardware. VMware Workstation and Oracle VirtualBox are examples of type 2 hypervisors.

Usages of VM

• VMs can run multiple operating system environments on a single physical computer (saves hysical space, time and management costs)
• Server virtualization
• Cloud services (i.e. Azure, AWS, GCP) are powered by VMs
• Testing and PoC purposes