🖥️ Virtualization¶

Understanding Virtual Machines, Hypervisors and the foundations of modern infrastructure.

Table of Contents¶

What is Virtualization?
Why Virtualization Exists
Physical Machines Before Virtualization
What is a Virtual Machine?
Hypervisors
Type 1 vs Type 2 Hypervisors
VirtualBox Overview
Host vs Guest Systems
Virtual Hardware
Virtual CPU
Virtual RAM
Virtual Storage
Virtual Network Interfaces
Virtual Disks
Snapshots
Resource Allocation
Advantages of Virtualization
Disadvantages of Virtualization
Real World Uses
Virtualization vs Containers
Why Born2beroot Uses Virtualization
Mental Model

1️⃣ What is Virtualization?¶

Virtualization is the process of creating a virtual version of a computer system.

Instead of running a single operating system directly on physical hardware, virtualization allows multiple isolated systems to run on the same machine.

Think of virtualization as:

Creating a computer inside another computer

2️⃣ Why Virtualization Exists¶

Before virtualization became common, organizations typically used:

1 Physical Server
        =
1 Operating System

This approach caused several problems:

Expensive hardware
Low resource usage
Difficult maintenance
Poor scalability

Many servers used only a small percentage of their available resources.

Example:

CPU Usage: 10%
RAM Usage: 15%
Disk Usage: 20%

Most of the hardware remained unused.

Virtualization was created to solve this problem.

3️⃣ Physical Machines Before Virtualization¶

Traditional infrastructure looked like this:

Server A → Database
Server B → Website
Server C → Mail Server
Server D → Backup System

Each service required its own machine.

Today, a single powerful server can host many virtual systems simultaneously.

4️⃣ What is a Virtual Machine?¶

A Virtual Machine (VM) behaves like a completely independent computer.

A VM has:

CPU
Memory
Storage
Network Interface
Operating System

Even though these resources are virtual, the operating system treats them as real hardware.

Example:

Physical Machine
      │
      ▼
 Hypervisor
      │
      ▼
 Virtual Machine
      │
      ▼
 Debian Linux

5️⃣ Hypervisors¶

A hypervisor is software responsible for managing virtual machines.

Its job is to:

Create virtual machines
Allocate resources
Isolate systems
Control access to hardware

Without a hypervisor, virtualization would not be possible.

Popular hypervisors:

VirtualBox
VMware
Hyper-V
KVM
Xen

6️⃣ Type 1 vs Type 2 Hypervisors¶

There are two main categories.

Type 1 Hypervisors¶

Run directly on hardware.

Hardware
    │
Hypervisor
    │
Virtual Machines

Examples:

VMware ESXi
Hyper-V Server
Xen

Type 2 Hypervisors¶

Run inside another operating system.

Hardware
    │
Host OS
    │
VirtualBox
    │
Virtual Machines

Examples:

VirtualBox
VMware Workstation

Born2beroot normally uses this model.

7️⃣ VirtualBox Overview¶

VirtualBox is one of the most popular desktop virtualization tools.

It allows users to:

Create VMs
Allocate resources
Manage virtual disks
Create snapshots
Configure networking

VirtualBox acts as the bridge between the host machine and the guest operating system.

8️⃣ Host vs Guest Systems¶

This distinction is extremely important.

Host¶

The host is:

The real machine

Examples:

Windows
macOS
Linux

Guest¶

The guest is:

The virtual machine

Examples:

Debian
Rocky Linux

Example:

Windows Host
      │
VirtualBox
      │
Debian Guest

9️⃣ Virtual Hardware¶

Every VM receives virtual hardware.

Examples:

Virtual CPU
Virtual RAM
Virtual Disk
Virtual Network Card

The guest operating system believes this hardware is real.

🔟 Virtual CPU¶

The virtual CPU represents processing power assigned to the VM.

Example:

Physical CPU = 8 cores

VM 1 = 2 cores
VM 2 = 2 cores
VM 3 = 2 cores
VM 4 = 2 cores

The hypervisor distributes resources between machines.

1️⃣1️⃣ Virtual RAM¶

Memory is also shared.

Example:

Physical RAM = 16 GB

VM A = 4 GB
VM B = 4 GB
VM C = 4 GB

Allocating too much memory may negatively impact the host system.

1️⃣2️⃣ Virtual Storage¶

A VM stores data inside virtual disks.

The guest operating system sees:

A normal hard drive

even though the disk is actually a file on the host machine.

1️⃣3️⃣ Virtual Network Interfaces¶

Virtual machines require network connectivity.

Virtual adapters allow:

Internet access
Communication between VMs
Communication with the host

1️⃣4️⃣ Virtual Disks¶

Virtual disks are files representing storage devices.

Common formats:

VDI
VHD
VMDK

The guest system treats these files as physical disks.

1️⃣5️⃣ Snapshots¶

Snapshots are one of the most useful virtualization features.

A snapshot records the state of a VM at a specific moment.

Example:

Clean Installation
      ↓
Snapshot
      ↓
Experiment
      ↓
Problem Occurs
      ↓
Restore Snapshot

Snapshots make testing much safer.

1️⃣6️⃣ Resource Allocation¶

Every VM consumes resources.

Administrators must decide:

CPU allocation
Memory allocation
Storage allocation
Network configuration

Poor allocation can reduce performance.

1️⃣7️⃣ Advantages of Virtualization¶

Benefits include:

✅ Isolation

✅ Easy testing

✅ Portability

✅ Lower hardware costs

✅ Better resource utilization

✅ Safer experimentation

1️⃣8️⃣ Disadvantages of Virtualization¶

Potential drawbacks:

❌ Resource overhead

❌ Increased complexity

❌ Additional management layers

❌ Hardware limitations

Despite these drawbacks, the benefits usually outweigh the costs.

1️⃣9️⃣ Real World Uses¶

Virtualization is used almost everywhere.

Examples:

Cloud providers
Development environments
Testing platforms
Corporate servers
Educational environments

Companies often run hundreds or thousands of virtual machines.

2️⃣0️⃣ Virtualization vs Containers¶

Students often confuse these concepts.

Virtual Machines¶

Include:

Operating System
Kernel
Applications

Containers¶

Share the host kernel.

They are lighter and faster but provide a different type of isolation.

Examples:

Docker
Podman

2️⃣1️⃣ Why Born2beroot Uses Virtualization¶

Virtualization provides:

Safety
Isolation
Reproducibility
Easy recovery

Students can experiment without risking their primary operating system.

If something breaks:

Delete VM
Create New VM
Continue Learning

2️⃣2️⃣ Mental Model¶

Think of a Virtual Machine as:

A complete computer
inside another computer

Think of the Hypervisor as:

The manager
of those computers

Final Mental Image¶

Physical Computer
        │
        ▼
   VirtualBox
        │
        ▼
   Debian VM
        │
        ▼
 Linux Administration

Virtualization creates a safe environment where systems can be studied, configured and maintained without affecting the real machine.