Skip to main content

Virtualization: Multiple Systems on One Machine

Virtualization runs multiple operating systems on one physical machine.

Here's the thing: Virtualization is full isolation. Each VM is independent. Use it when you need that.

What Virtualization Is​

Virtualization:

  • Full isolation
  • Independent systems
  • Resource allocation
  • Snapshot and cloning

My take: Virtualization is like multiple computers in one box. Full isolation.

Types of Virtualization​

Type 1: Bare Metal​

Examples: VMware ESXi, Hyper-V, KVM

Characteristics:

  • Runs directly on hardware
  • Best performance
  • Used in data centers

My take: Type 1 = bare metal. Best performance. Used in production.

Type 2: Hosted​

Examples: VirtualBox, VMware Workstation

Characteristics:

  • Runs on host OS
  • Easier setup
  • Good for development

My take: Type 2 = hosted. Easier setup. Good for learning.

KVM: Kernel Virtual Machine​

KVM Basics​

# Check if KVM supported
lsmod | grep kvm

# Install KVM
sudo apt install qemu-kvm libvirt-daemon-system

# List VMs
virsh list --all

# Start VM
virsh start vmname

My take: KVM is Linux virtualization. Powerful. Used in production.

When to Use Virtualization​

Use when:

  • Need full isolation
  • Different operating systems
  • Testing environments
  • Resource allocation

Don't use when:

  • Containers are enough
  • Don't need full isolation
  • Performance critical

My take: Virtualization is for full isolation. Use it when you need that.

Containers vs Virtualization​

Containers:

  • Share host kernel
  • Lightweight
  • Fast startup

Virtualization:

  • Full isolation
  • Independent OS
  • More overhead

My take: Containers for applications. Virtualization for full isolation. Choose based on needs.

Common Mistakes (I've Made These)​

  1. Using VMs when containers work: Containers are lighter. Use them when possible.

  2. Not allocating resources: VMs need resources. Allocate properly.

  3. Too many VMs: VMs consume resources. Don't create too many.

  4. Not understanding overhead: Virtualization has overhead. Consider it.

  5. Security: VMs are isolated. But still secure them.

Real-World Examples​

Check KVM Support​

lsmod | grep kvm

List VMs​

virsh list --all

What's Next?​

Now that you understand virtualization, you understand isolation. Or review what you've learned. You're ready.

Personal note: Virtualization seemed complex at first. Then I used it. Now I understand it. Virtualization is powerful. Use it when you need full isolation.