Virtual Machine

: virtual environment that functions as a virtual computer system with its own CPU, memory, network interface, and storage, created on a physical hardware system (located off- or on-premises)

 

 

The physical machines, equipped with a hypervisor such as Kernel-based Virtual Machine (KVM), is called the host. The many VMs that use its resources are guests.

 

Hypervisor

• treats compute resources—like CPU, memory, and storage—as a pool of resources that can easily be relocated between existing guests or to new virtual machines.
• separates the machine’s resources from the hardware and provisions them appropriately so they can be used by the VM.
• manages the hardware and separates the physical resources from the virtual environments
• 단일 하드웨어에서 여러 다른 가상 머신을 호스팅할 수 있는 프로그램
• 물리적 하드웨어에 설치된 소프트웨어 계층

 

VMs allow multiple different operating systems to run simultaneously on a single computer. Each operating system runs in the same way an operating system or application normally would on the host hardware, so the end user experience emulated within the VM is nearly identical to a real-time operating system experience running on a physical machine. 

 

Server consolidation is a top reason to use VMs. By virtualizing your servers, you can place many virtual servers onto each physical server to improve hardware utilization.

• No need to purchase additional physical resources, like hard drives or hard disks, as well as reduced need for power, space, and cooling in the datacenter.
• provide additional disaster recovery options by enabling failover and redundancy that could previously only be achieved through additional hardware.
• provides an environment that is isolated from the rest of a system, so whatever is running inside a VM won’t interfere with anything else running on the host hardware.