13.0 Virtualization

Tags: #◇Computer Science #◇CCICOMP #◇Virtualization #◇M4

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◇Overview

This document introduces Virtualization, the process of creating virtual representations of physical computing resources such as operating systems, storage devices, and computer networks. It explains the concept of Virtual Machines (VMs), the role of hypervisors, and the different types of virtualization available. The notes also highlight the key benefits of implementing virtualization, including resource optimization and improved system isolation.

◇Key Definitions

Virtualization: The creation of virtual, rather than physical, versions of computing resources, including hardware platforms, operating systems, storage devices, and network resources. Virtual Machine (VM): An emulation of a computer system. It allows multiple isolated operating systems to run concurrently on a single physical machine, with each VM acting as a separate, independent system. Hypervisor (Virtual Machine Monitor): A specialized software or firmware layer that creates, manages, and runs virtual machines. It creates an abstraction layer between the VMs and the underlying physical hardware.
Type 1 (Bare Metal) Hypervisor: Runs directly on the host's hardware to control the hardware and manage guest operating systems.
Type 2 (Hosted) Hypervisor: Runs on top of a conventional operating system just as other computer programs do. Containers: An OS-level virtualization method that provides lightweight, isolated application environments. Unlike VMs, multiple containers share the same host OS kernel, significantly reducing resource overhead (e.g., Docker).

◇Theoretical Framework

Types of Virtualization

Virtualization can be applied across various layers of an IT infrastructure:

1. Hardware Virtualization:
   Involves virtualizing physical components like CPUs, memory, and storage devices.
   VMs run full operating systems on the same physical machine without direct, unfiltered access to the underlying hardware.
2. Operating System Virtualization (Containerization):
   Utilizes containers to run isolated applications.
   Multiple applications share the exact same underlying OS, providing a highly efficient and lightweight alternative to full hardware VMs.
3. Network Virtualization:
   Involves the efficient sharing and abstraction of physical network resources among VMs.
   Utilizes Virtual Network Devices such as Virtual Network Interface Cards (NICs) and virtual switches.
4. Storage Virtualization:
   Abstracts physical storage (e.g., SSD arrays, cloud storage) into unified virtual drives.
   Enables highly efficient resource management, pooling, and dynamic scaling.

VM Lifecycle and Management

The process of creating and managing a Virtual Machine involves several steps managed by the hypervisor: Allocation: Assigning virtual CPUs, memory, and storage to the newly created VM. Network Configuration: Setting up virtual network interfaces to allow the VM to communicate. Execution: The hypervisor continuously manages resource allocation and ensures isolation between the VM and the host.

Benefits of Virtualization

Implementing virtualization yields several significant advantages: Resource Optimization: Maximizes the utilization of physical hardware by securely sharing resources among multiple virtual environments. Ease of Backup and Recovery: VMs can be easily snapshotted (saving the current state) and cloned, making disaster recovery straightforward. Isolation: Provides secure, sandbox environments ideal for software testing and deployment without posing any risk to the host machine or other VMs.

◇References & Navigation

• Previous Topic: ◇Computer Software - Applications and Programming Software
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• Related Notes: ◇Virtual Memory & Address Translation (Paging & TLB), ◇Computer Software - OS and Utility Programs