Virtualization Concepts Explained

Key Concepts

• Virtualization
• Hypervisor
• Virtual Machine (VM)
• Guest Operating System
• Host Operating System
• Virtualization Types
• Resource Allocation
• Snapshot
• Live Migration
• Containerization

Virtualization

Virtualization is the process of creating a virtual version of something, such as hardware platforms, storage devices, or network resources. It allows multiple operating systems to run on a single physical machine.

Example: A single server can run multiple virtual machines, each with its own operating system, applications, and data.

Hypervisor

A hypervisor, also known as a virtual machine monitor (VMM), is software that creates and runs virtual machines. It allows multiple operating systems to share a single host's hardware resources.

Example: VMware ESXi and Microsoft Hyper-V are examples of hypervisors that manage virtual machines on a physical server.

Virtual Machine (VM)

A virtual machine is a software-based emulation of a physical computer. It runs its own operating system and applications, isolated from the host and other VMs.

Example: A VM can be created to run a specific application or to test a new operating system without affecting the host system.

Guest Operating System

The guest operating system is the operating system running within a virtual machine. It is isolated from the host operating system and other VMs.

Example: A Windows 10 VM running on a Linux host has Windows 10 as the guest operating system.

Host Operating System

The host operating system is the operating system running on the physical machine that hosts the virtual machines. It manages the hardware resources and the hypervisor.

Example: A Linux server running VMware ESXi has Linux as the host operating system.

Virtualization Types

There are two main types of virtualization: Type 1 (bare-metal) and Type 2 (hosted). Type 1 hypervisors run directly on the hardware, while Type 2 hypervisors run on a host operating system.

Example: VMware ESXi is a Type 1 hypervisor, while VMware Workstation is a Type 2 hypervisor.

Resource Allocation

Resource allocation in virtualization involves distributing the physical resources of the host machine, such as CPU, memory, and storage, among the virtual machines.

Example: A host with 32GB of RAM can allocate 8GB to one VM, 16GB to another, and 8GB to a third VM.

Snapshot

A snapshot is a point-in-time copy of a virtual machine's state, including the operating system, applications, and data. It allows for easy rollback to a previous state.

Example: Taking a snapshot before installing a new application allows you to revert to the previous state if the installation fails.

Live Migration

Live migration is the process of moving a running virtual machine from one physical host to another without downtime. It is used for load balancing and maintenance.

Example: Moving a VM from a server with high CPU usage to a less utilized server to balance the load.

Containerization

Containerization is a form of virtualization where applications run in isolated user spaces called containers, sharing the same operating system kernel. It is lighter than traditional virtualization.

Example: Docker containers can run multiple applications on a single host, each in its own isolated environment.