Virtualisation Basics

Before the concept of virtualization, the rule of thumb in IT was:
“One server = one application.”

In the early days, digital services were run on physical machines, and each machine typically had a single, clear purpose, such as hosting a website or storing data. As businesses added more services, they naturally increased the number of physical servers, and the “one job per box” approach became the standard for building reliable systems.

This meant that if a company wanted to run a website, a database, an email service, and an internal app, they would need separate physical servers for each one. The problems were obvious:

• High cost: Buying multiple physical servers is expensive, not just the hardware, but also electricity, cooling, maintenance, and data center space.
• Low utilization: Most applications don’t use the server’s full capacity. Many servers stayed at 5–20% usage, wasting CPU, memory, and storage resources.
• Slow deployment: Setting up new physical servers could take days or weeks.
• Hard to scale: If an application suddenly needed more resources, you often had to buy yet another server.

In short, companies were paying a lot for hardware that wasn’t being fully utilized.

The Need for Sharing Hardware Safely and Efficiently

Virtualization introduced a new idea:
“What if multiple applications could share the same physical server safely?”

A virtualization layer, called a hypervisor, was introduced to act as a referee between virtual machines and allow each virtual computer to behave independently, like a physical computer.

The Building Analogy

Imagine if one single person lives alone in an entire 10-floor building:

• The person uses only one floor but must maintain the entire building: electricity, cleaning, water, and security.
• Most of the building stays empty and wasted.
• It’s expensive, inefficient, and unnecessary for his needs.

Now imagine dividing the building into separate apartments:

• Each apartment has its own door, walls, kitchen, and privacy.
• Different people can live independently without bothering each other.
• They all share the building’s main structure: electricity, water, and elevators, making it cheaper and more efficient for everyone.

This is virtualization:

• The building = the physical server
• The apartments = virtual machines
• The tenants = applications or operating systems
• The building manager = the hypervisor (the software that divides the building safely)

Each virtual computer, known as a Virtual Machine (VM), acts as an independent system with its own operating system, apps, and settings, even though they all share the same physical hardware underneath.

Hypervisor (The Building Manager)

A hypervisor is the core technology behind virtualization. It's the software that creates and manages virtual machines.

It is a special piece of software that:

• Divides a physical computer into multiple virtual ones.
• Gives each virtual machine its own share of CPU, memory, and storage.
• Keeps everything isolated and safe.
• Manages the lifecycle of virtual machines (start, stop, pause, clone, delete).

Hypervisors have two main types of implementation, each of which is used for specific scenarios, from home labs to large data centers:

• Type 1 hypervisors run directly on the physical hardware, making them fast, efficient, and ideal for servers and professional environments.
• Type 2 hypervisors run within an existing operating system, making them easier to install and ideal for learning, testing, or small setups.

Below is a table showing which use case is best suited to each hypervisor type. The use cases can run on both hypervisor types, but it's not the best approach given the main objectives of each.

When using virtualization to test malicious files, care should be taken to ensure that the host machine does not become infected by the malware being tested in the guest machine. One approach is to use different operating systems for the guest and host machines, or to isolate the guest machine so that it does not communicate with the host.

Virtual Machines (The Apartments)

A Virtual Machine (VM) is a virtual computer created by the hypervisor.
Even though it’s virtual, it behaves as a real machine:

• It has its own virtual CPU, RAM, storage, and network.
• It can run any operating system (Windows, Linux, etc.).
• It’s completely isolated from other VMs. This means that if one VM breaks, the others continue to work.

You can deploy VMs on your own computer using tools such as Oracle VirtualBox and VMware Workstation. This type of software acts as a type 2 hypervisor and lets you run multiple operating systems, such as Windows, Linux, and macOS.

Since you have learned what a hypervisor and VM are, let's take some examples where you might need them:

• You need to work on a different OS like Kali Linux, but you can't buy another whole system, so you install a hypervisor and run a Kali Linux VM on it.
• You want to test whether a file is malicious, so you set up an isolated virtual machine to protect your main computer from being infected.

Containers (The Rooms Inside the Apartment)

A container is a lightweight, isolated environment that runs a single application and all the necessary components to support it. Instead of bringing a whole separate operating system, a container borrows the core of the existing system by running on the kernel, which is the part of an operating system that communicates with the hardware and manages resources such as memory and running programs.

Because containers share this kernel, they start quickly and use fewer resources than full virtual machines, but it also means they must match the host system’s type. For example, you can’t run a Windows container on a Linux machine.

Containers behave like small, self-contained spaces because:

• They package the application and its dependencies (libraries, tools, versions).
• They share the host’s operating system, so they start almost instantly.
• They remain isolated from each other, so a misbehaving container doesn’t affect the others.
• They can run consistently on any machine, making them perfect for development, testing, and scalable deployments.

The easiest way to deploy containers in a VM is using Docker.
Docker is an open-source software platform that simplifies the process of building, deploying, and running applications using containerization.

The image below illustrates the relationship between Hypervisors, VMs, and containers:

In summary, VMs provide the “full apartment” with maximum separation and flexibility, while containers offer lightweight “rooms” ideal for scalable, fast-deploying applications.

After learning about virtualization, you were hired to be responsible for the virtual environment for AutoGalo, a company that has recently started using virtual machines.
In this company, they use an application called Virtualization Manager. This application provides a clear view of the overall status of an entire virtualization environment, providing details of each virtualized instance and the physical hosts. It also enables you to run actions and manage the VMs you create.

Your manager has asked you to investigate an issue with the email service. Essentially, everyone in the company stopped receiving emails today, and no one knows what happened.

Open the Virtualization Manager site by clicking the View Site button below, and let's investigate!

Analyzing Virtual Machine States

In the home screen, you should see three main sections:

• Summary: Provides a generic view of the state of the environment.
• Virtual Machines: Provides details of each VM and enables you to run actions on them.
• Hosts: Displays usage and performance details for each physical server.

Go to the Virtual Machines section and look for the VM with the name Mail-SERVER:

Looks like this virtual machine has entered an Error state. Let's try rerunning this VM using the Blue Square Button to restart it.

After running again, it appears to be working correctly, with no errors!

Creating a Virtual Machine

As part of your routine, you create virtual machines for other teams. After resolving the email server issue, you received a task to create a VM to support the marketing team's website.

Now, let's create a VM to host their marketing website. In the Virtual Machines section, locate the + Create VM button on the top right side of the Virtual Machines section and click on it.

You should fill out the form with how much hardware your virtual machine will be using:

• Name: Marketing-VM
• CPU Cores: 4
• Memory (GB): 8
• Disk Size (GB): 100

Then click on Create VM

Now, at the top of the list of Virtual Machines, you should see your created VM:

Analyzing Hardware Usage

Another routine task you have is to manage the health of the physical servers and report status to your manager. Go to the Hosts section at the bottom of the page:

By analyzing it, we can identify:

• HV-PROD-01 has the capacity to host more VMs.
• HV-PROD-02 is almost operating at 100% of its capacity, and we might need to report this!
• HV-BACKUP-01 is disconnected and does not host any VMs.

Now, answer the following task questions to conclude your shift as the responsible for virtualization in AutoGalo!

In this room, you learned why virtualization is such a critical foundation in modern IT, both for maximizing hardware efficiency and for safely isolating environments.

Key Terminology

Let's quickly review some concepts we learned in this room:

• Virtualization: Enables a single physical computer to act like multiple separate computers.
• Hypervisor: The “manager” software that makes and runs the virtual computers.
• Virtual Machine (VM): A whole virtual computer inside the real one, with its own system.
• Container: A small, isolated box for one app that shares the same system as the host.
• Container Images: A pre-packed recipe/template used to create containers.
• Network Ports: Special numbered entry points that apps use to talk over the network.

We also concluded that the key benefits of virtualization are:

• Cost savings
• Better resource usage
• Safe testing for cyber security
• Faster deployment
• Flexibility
• Portability
• Scalability
• Centralized Management

Further Learning

Through hands-on practice, you experienced how virtualization simplifies and accelerates application deployment, providing a fast and secure way to run applications consistently.

With these fundamentals, you are ready to explore the Cloud concept in the Cloud Computing Fundamentals room, which uses virtualization, containerization, and automation to provide scalable, on-demand services!