What is Virtual Machine?

A virtual machine could be a software package that not solely exhibits the behaviour of a unique computer , however is additionally capable of playing tasks like running applications and programs like an independent computer. It is usually known as guest created within another computing environment called as “host”. Several Virtual Machines can exist within a single host at a time. Virtual Machines are becoming more common with evolution of technology. Virtual Machines are often developed to perform variety of tasks that are different than the tasks performed in host environment. Virtual machines are executed by software emulation methods or hardware virtualization techniques depending on their use and level of correspondence to any physical computer. Virtual Machines can be classified into two sets: 1. System Virtual Machine - A system platform that supports the sharing of the host computer's resources between multiple virtual machines, each running with its own copy of the software package. The virtualization technique is provided by a software system layer referred to as a hypervisor, which might run either on bare machine.Virtual Machine Monitor owns the important system resources and allocates resources to guest OS by partitioning or time-sharing.

2. Process Virtual Machine – It is additionally referred to as application Virtual Machine. It is designed to supply a platform for freelance programming surroundings that masks the data of the underlying hardware or OS and permits to execute the program in same approach or on alternative platform.

Virtual Machines uses hardware more efficiently, which in turn lowers the quantity of hardware and reduces power and cooling demand. Virtual Machines have several uses but generally they are deployed when the need for different OS and processing power are needed for running different applications. The Different types of VM applications are - VirtualBox, Windows Virtual PC, Parallels Desktop, etc. Virtualization Technology allows you to share a system with virtual environments. Resources are divided as needed from the physical environment to the VMs. When the VM is running and a user issues an instruction that requires additional resources from the physical environment, the hypervisor schedules the request to the physical system’s resources so that the virtual machine’s operating system and applications can access the shared pool of physical resources. There are 2 types of Hypervisor - 1. Type 1 Hypervisor is on Bare Metal. KVM is an Example of Type 1 Hypervisor. 2. Type 2 Hypervisor is Hosted. VMware Workstation and Oracle VirtualBox are examples of type 2 hypervisors.

How a Virtual Machine Works? VM architecture can be separated into four different parts, listed from the bottom up:

- An underlying system which includes the physical machine and its OS. Bare metal hypervisors do not require an underlying operating system at this layer.

- A hypervisor which acts as a communication and translation layer.

- Multiple VM that use the host’s resources by communicating with the hypervisor.

- Applications and processes that run on each guest’s operating system.

The hypervisor needs to be appropriately configured before deploying any virtual machines. Using KVM, an open source virtualization technology built into Linux, administrators can create virtual machines from a command line interface.