Description

What is KVM? A Simple Guide to Kernel-based Virtual Machine

Virtualization is a very useful tool in the world of computers. It lets you run more than one operating system on one computer, which saves you money, time, and energy. KVM, or Kernel-based Virtual Machine, is one of the most important technologies in this field.

This article is for you if you're new to virtualization or just want to know what KVM is and how it works in simple terms.

What is KVM?

The Linux operating system has a virtualization technology called KVM (Kernel-based Virtual Machine). This lets you turn your Linux computer into a hypervisor, which means it can run more than one virtual machine (VM) at once.

Every virtual machine behaves like a distinct physical computer. Even though all the VMs are on the same machine, you can run different operating systems on each one, like Linux, Windows, etc.

How does KVM work?

The Linux kernel (the main part of the operating system) has KVM built right in. That's why it's called "kernel-based." It makes good use of the kernel's features to manage virtual machines.

Your processor needs to support hardware virtualization, like Intel VT or AMD-V, in order to use KVM. These features make virtualization faster and safer by making it easier for the CPU to handle multiple environments.

When you set up a KVM-based system, it comes with:

• KVM module in the Linux kernel (already in most modern Linux distributions)
• QEMU is an emulator that works with KVM.
• Libvirt is a program that helps you manage virtual machines.
• Virt-manager (a graphical interface that makes it easy for users to manage VMs)

Why should you use KVM?

For a lot of reasons, KVM has become a popular choice for virtualization:

1. Open Source and Free: KVM is free to use because it is part of the Linux kernel. You don't need to buy expensive licenses.
2. Performance: KVM runs inside the Linux kernel and uses hardware support, so it works almost as fast as real hardware.
3. Security: Each virtual machine runs in its own separate space. KVM also works with SELinux and AppArmor.
4. Scalability: KVM can run dozens or even hundreds of VMs on one server, depending on the hardware.
5. Compatibility: KVM works with many operating systems, like Linux, Windows, and BSD.

Where is KVM used?

Many businesses use KVM:

• Cloud computing: Used by platforms like OpenStack and Google Cloud.
• Data centers: Helps manage server loads and optimize space.
• Developers: Use it for testing software across different environments.
• Education: Great for learning virtualization and system administration.

Important Words to Know

• Virtual machine (VM): A computer that runs inside another computer.
• Hypervisor: Software that creates and manages virtual machines.
• Host: The physical machine that runs the hypervisor.
• Guest: The virtual machine's operating system.

How to Get KVM Up and Running?

You can easily install KVM if you use a Linux distribution like Ubuntu, Fedora, or CentOS. For example, on Ubuntu:

sudo apt install qemu-kvm libvirt-daemon-system virt-manager

Once installed, use Virt-Manager to create and manage virtual machines through a user-friendly interface.

KVM's limits

KVM is powerful, but has a few limitations:

• Learning curve: It may take time to learn the tools and commands.
• Linux-only: KVM is not available for Windows or macOS.
• No GUI on some servers: Some Linux servers need CLI to manage VMs.

However, with some practice, these challenges are manageable.

Last Thoughts

Most Linux systems come with KVM, which is a free, fast, and safe way to run multiple operating systems at once. KVM gives you the tools you need to run multiple operating systems quickly and easily, whether you're a system administrator, developer, or just curious about how to do it.

It's open-source, has a lot of support, and is trusted by some of the biggest names in cloud computing. If you need virtualization on Linux, KVM is one of the best options.

You're one step closer to becoming an expert in virtual machines now that you know the basics of KVM!