Cloud Computing and Virtualization - SSS 3 Digital Technologies
CLOUD COMPUTING AND VIRTUALIZATION
Class: SSS 3
Term: First Term
Week: 8
Duration: 80 Minutes (Double Period)
Topic: Cloud Computing and Virtualization
Learning Objectives
By the end of the lesson, students should be able to:
- Explain the meaning of virtualization and cloud computing.
- Describe virtual machines and explain how they work.
- Explain the meaning and uses of remote servers.
- Identify common examples of cloud computing services.
- Explain the relationship between virtualization and cloud computing.
- State the benefits and limitations of using cloud services.
1. Introduction
Modern computing involves more than using a physical computer in a classroom, office or home. People can store files online, use applications through the internet, and access computing resources located in distant data centres. These technologies make it possible to work with information without keeping every file or application on a personal computer.
Two important technologies that support this approach are cloud computing and virtualization. They help individuals and organisations use computing resources more flexibly and efficiently.
2. Meaning of Virtualization
Virtualization allows one physical computer to act as though it were several separate computers. Each virtual environment can be configured to perform particular tasks, depending on the resources available.
How Virtualization Works
- A physical computer or server provides the hardware resources, including its processor, memory and storage.
- Virtualization software manages how these resources are shared.
- The software creates virtual environments that behave like separate computing systems.
- Each environment can run its own operating system and applications, subject to the available hardware and software configuration.
Examples of Virtualization
- Running Linux inside a virtual machine on a Windows computer.
- Creating several virtual servers on one powerful physical server.
- Creating virtual storage or network resources through software.
3. Virtual Machines
Components of a Virtual Machine
- Virtual processor: Provides processing resources to the virtual machine.
- Virtual memory: Provides the memory allocated to the virtual machine.
- Virtual storage: Provides disk space for its operating system, files and applications.
- Guest operating system: The operating system installed inside the virtual machine.
- Virtualization software: Creates and manages the virtual machine.
Hypervisor
A hypervisor is software or a software layer that creates and manages virtual machines by allocating physical computing resources to them.
There are two common types:
- Type 1 hypervisor: Runs directly on the physical hardware. It is commonly used in servers and data centres.
- Type 2 hypervisor: Runs as an application on an existing operating system. It is often used on personal computers for learning, testing and development.
Uses of Virtual Machines
- Testing software without changing the main computer's operating system.
- Learning different operating systems.
- Running applications that require a different operating environment.
- Consolidating several server workloads onto fewer physical machines.
- Creating separate environments for development and testing.
4. Meaning of Cloud Computing
Instead of purchasing and maintaining every computing resource locally, a user or organisation can obtain services from a cloud provider. The provider manages the underlying infrastructure, while the user accesses the service according to the service arrangement.
Examples of Cloud Computing
- Online storage: Google Drive, Microsoft OneDrive and Dropbox.
- Online office applications: Google Docs and Microsoft 365 online services.
- Cloud computing platforms: Amazon Web Services (AWS), Microsoft Azure and Google Cloud.
- Web-based email: Gmail and Outlook on the web.
- Online collaboration: Services that allow users to share documents and work together remotely.
5. Remote Servers
Remote servers may be located in a company's server room or in a large data centre. Users can access their services through a local network or the internet, depending on the server's configuration and security settings.
Uses of Remote Servers
- Hosting websites and web applications.
- Storing files and databases.
- Sending and receiving email.
- Running applications for users in different locations.
- Providing shared computing resources to organisations.
How a Remote Server Works
- A user makes a request using a computer, phone or other connected device.
- The request travels through a network to the remote server.
- The server processes the request or retrieves the required information.
- The server sends a response back to the user's device.
For example, when a student opens a file stored in an online drive, the student's device communicates with the service's servers to retrieve the file.
6. Relationship Between Virtualization and Cloud Computing
Virtualization and cloud computing are related, but they do not mean exactly the same thing.
- Virtualization is a technology that allows computing resources to be represented and managed as virtual resources.
- Cloud computing is a way of delivering computing services to users over a network, often with on-demand access and flexible resource allocation.
Cloud providers frequently use virtualization to run many virtual machines on physical servers. This helps them allocate computing resources to different customers and services. However, cloud computing can also use other technologies, and virtualization can be used without cloud computing.
| Virtualization | Cloud Computing |
|---|---|
| Creates virtual versions of computing resources. | Delivers computing services over a network. |
| Can operate on a local computer or an organisation's own server. | Commonly allows access to resources hosted by a service provider. |
| Helps share and organise hardware resources. | Helps users obtain computing resources when required. |
| A virtual machine can run without being part of a public cloud. | A cloud service may use virtualization as part of its infrastructure. |
7. Common Cloud Service Models
| Model | Meaning | Example of Use |
|---|---|---|
| IaaS Infrastructure as a Service |
Provides computing infrastructure such as virtual machines, storage and networking. | Renting a virtual server to host a website. |
| PaaS Platform as a Service |
Provides a platform and tools for building, testing and deploying applications. | Developing an application without managing all the underlying server infrastructure. |
| SaaS Software as a Service |
Provides software that users access over a network, often through a web browser or application. | Using an online document editor or web-based email service. |
8. Benefits of Cloud Computing and Virtualization
Benefits of Cloud Computing
- Accessibility: Users can access supported services from different locations with an internet connection.
- Scalability: Computing resources can often be increased or reduced as needs change.
- Collaboration: Multiple users can work on shared files and applications.
- Reduced initial hardware costs: Users may avoid purchasing all the infrastructure themselves.
- Maintenance: The provider manages many aspects of the underlying infrastructure, depending on the service.
Benefits of Virtualization
- Improves the use of available physical hardware.
- Allows different operating systems to run on one physical computer.
- Supports software testing in separate environments.
- Can reduce the number of physical servers an organisation needs.
- Makes it easier to create, copy and manage computing environments.
9. Limitations and Risks
Limitations of Cloud Computing
- Internet dependence: Some cloud services become difficult or impossible to use when the connection is unavailable.
- Security and privacy: Poor account security or incorrect settings can expose information.
- Recurring costs: Subscription or usage charges may accumulate over time.
- Service interruptions: A provider's outage can temporarily prevent access.
- Provider dependence: Moving data and applications to another provider may require time, planning or additional cost.
Limitations of Virtualization
- Virtual machines share physical resources, so too many may reduce performance.
- Running virtual machines requires sufficient memory, processing power and storage.
- Virtualization software must be configured and maintained correctly.
- A failure of the host computer may affect the virtual machines running on it.
10. Practical Class Activity
Activity A: Identify Cloud Services
- List three online services you have used or heard about.
- Identify which ones allow users to store files, edit documents or communicate online.
- Explain how one of these services can be useful to a student.
Activity B: Virtualization Discussion
- Imagine a school has one powerful computer that needs to support different operating systems for practical lessons.
- Explain how virtual machines could help the school.
- State two hardware resources the school should consider before creating several virtual machines.
Activity C: Compare the Technologies
In your notebook, write two differences between virtualization and cloud computing. Give one example of each.
11. Summary
Virtualization creates virtual versions of computing resources and allows a physical computer to host separate virtual environments. A virtual machine behaves like a computer and can run its own operating system and applications. A hypervisor manages virtual machines and allocates resources to them.
Cloud computing delivers services such as storage, software, processing power and networking over a network, usually the internet. Remote servers provide services to users from another location. Cloud computing often uses virtualization, but the two technologies are not the same. Both offer benefits and have limitations relating to performance, cost, security and availability.
12. Evaluation Questions
- What is virtualization?
- Define a virtual machine and state three of its components.
- What is a hypervisor? Name its two common types.
- Explain cloud computing and give three examples of cloud-based services.
- What is a remote server? State three uses of remote servers.
- Explain two differences between virtualization and cloud computing.
- Differentiate between IaaS, PaaS and SaaS.
- State three benefits and three limitations of cloud computing.
13. Assignment
- Explain the meaning of cloud computing and virtualization in your own words.
- Describe the difference between a physical computer and a virtual machine.
- Write short notes on IaaS, PaaS and SaaS, giving one suitable example of each.
- State four safety measures users should take when storing information in the cloud.
- Explain why a school might use virtual machines in a computer laboratory.
14. Interactive Quiz
Choose the correct answer for each question, then click Check Answers to see your score.
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