Cloud Computing and VDI
Virtualization at Scale
1 Purpose
Virtualization is the foundational technology that makes cloud computing possible. This document provides a high-level overview of the basic models of cloud computing and introduces Virtual Desktop Infrastructure (VDI), a technology that uses virtualization to deliver entire desktop environments to users over a network.
2 What You’ll Accomplish
By the end of this reading, you will be able to:
- Define the three main cloud service models: IaaS, PaaS, and SaaS.
- Define the three main cloud deployment models: Public, Private, and Hybrid.
- Explain the concept of Virtual Desktop Infrastructure (VDI).
This reading maps to the following program and course learning outcomes:
- Course Learning Outcomes (CLOs):
- 1. Identify hardware and basic network components: This topic explains how virtualization concepts are applied at scale in cloud environments.
This exercise develops the following skills, which align with the O*NET SOC Code 15-1232.00 for Computer User Support Specialists.
| Learning Objective | O*NET KSAs | Technologies Used |
|---|---|---|
| Define cloud service and deployment models. | Knowledge: Computers & Electronics, Telecommunications Abilities: Category Flexibility |
IaaS, PaaS, SaaS, Public/Private Cloud |
| Explain the concept of VDI. | Knowledge: Computers & Electronics Skills: None |
VDI |
3 Cloud Computing Service Models
Cloud computing is often broken down into three main service models, which can be thought of as different levels of a pyramid. The model you choose determines how much of the “stack” you are responsible for managing.
3.1 Infrastructure as a Service (IaaS)
IaaS is the most basic level. The cloud provider gives you access to fundamental computing infrastructure: virtual machines, storage, and networking. You are responsible for managing the operating system, middleware, and all your applications.
- Analogy: IaaS is like leasing a plot of land. You are given the raw ground and utility hookups, but you have to build the house, put in the furniture, and live in it.
- Examples: Amazon Web Services (AWS) EC2, Microsoft Azure VMs, Google Compute Engine.
3.2 Platform as a Service (PaaS)
PaaS provides a platform that allows customers to develop, run, and manage applications without the complexity of building and maintaining the underlying infrastructure. The provider manages the operating system, middleware (like databases or web servers), and runtime.
- Analogy: PaaS is like renting a fully furnished apartment. The building, utilities, and major appliances are all managed for you. You just need to bring your personal belongings (your code and data).
- Examples: Heroku, AWS Elastic Beanstalk, Google App Engine.
3.3 Software as a Service (SaaS)
SaaS is the most common model. The provider gives you access to a complete, ready-to-use software application that runs on their infrastructure. You access it through a web browser or a client application. You manage nothing about the underlying infrastructure.
- Analogy: SaaS is like staying in a hotel. Everything is provided and managed for you: the room, the cleaning, the food. You just show up and use the service.
- Examples: Google Workspace (Gmail, Docs), Microsoft 365, Salesforce, Dropbox.
4 Cloud Deployment Models
- Public Cloud: The infrastructure is owned and operated by a third-party cloud provider (like AWS, Google, Microsoft) and delivered over the internet.
- Private Cloud: The infrastructure is operated solely for a single organization. It can be managed internally or by a third party and can be hosted on-premises or in a data center.
- Hybrid Cloud: A combination of public and private clouds, bound together by technology that allows data and applications to be shared between them.
5 Virtual Desktop Infrastructure (VDI)
Virtual Desktop Infrastructure (VDI) is the practice of hosting a desktop operating system within a virtual machine running on a centralized server. Users can then access this virtual desktop from any device (like a laptop, tablet, or thin client) over the network.
- On-Premises VDI: The servers that host the virtual desktops are located in the company’s own data center.
- Examples: VMware Horizon, Citrix Virtual Apps and Desktops.
- Cloud-Based VDI (Desktop as a Service - DaaS): The servers are hosted by a public cloud provider. This simplifies management for the company.
- Examples: Azure Virtual Desktop, Amazon WorkSpaces.
The key benefit of VDI is that it allows IT to centralize, secure, and manage user desktops from a single location, rather than having to manage hundreds or thousands of individual physical PCs.
6 Reflect and Review
Now that you have reviewed this document, take a moment to reflect on your learning in your Microsoft Teams Student Notebook:
- 3 cloud service models.
- 2 cloud deployment models.
- 1 question you still have about VDI.
Answer these questions in your notebook to solidify your understanding:
- You want to rent a virtual server from a cloud provider to install and manage your own Linux operating system and web server software. Which cloud service model would you use?
- Your company uses Google Docs for all its word processing. What type of cloud service model is this?
- What is the primary benefit of VDI?
- What is the key difference between a public cloud and a private cloud?