What is KVM Virtualization: Kernel-based Virtual Machine Full Guide

Explore the power of KVM Virtualization in this comprehensive blog post. Learn about its key features, benefits, real-world applications, and how to set it up. Ideal for beginners and experts alike looking to harness the potential of KVM in their Linux systems.

Updated: 25 Dec, 23 by Lisa P 15 Min

List of content you will read in this article:

In the dynamic world of computing, virtualization (virtualisation) is a key technology. It helps us use hardware resources efficiently and run applications in separate environments. One popular virtualization solution is the Kernel-based Virtual Machine (KVM), especially for Linux Operating System. This blog post will explore KVM in an easy-to-understand way. We’ll look at its main parts, how it works with tools like QEMU and Libvirt, ways to manage it, its performance and security benefits, and how it’s used in the real world.

Virtualization is like having a superpower that lets one computer do the job of multiple computers. It creates a kind of magic layer that separates computer hardware from the software running on it. With virtualization, you can split a single physical computer into several ‘virtual’ computers, each running its operating system and applications as if they were separate machines.

Types of Virtualization

  1. Desktop Virtualization: This type lets you run multiple ‘virtual’ desktop computers on a single physical one. It’s like having several different computers all in one.
  2. Network Virtualization: This type divides the available bandwidth of a network into separate channels. Each channel can be assigned to a different server or device, just like having multiple private roads on a single highway.
  3. Application Virtualization: This type allows an application to run on a different operating system than it was originally designed for. It’s like being able to run a Windows program on a Mac.
  4. Storage Virtualization: This type makes physical storage from multiple network storage devices appear as if it’s a single storage unit. It’s like having a single closet for all your clothes even if they’re in different drawers.

Benefits of Virtualization

Here are some of the benefits of Virtualization:

Save Money

Virtualization can help you cut down on IT expenses. By using virtualization, you can run multiple applications on a single server, which means you need fewer servers. Fewer servers mean less money spent on hardware and energy costs.

Linux  VPS
Need Affordable VPS Hosting

Starting From $5.99/Monthly

🏅 Fast Delivery
🏅 25+ Data Centers

Increase Efficiency

With virtualization, you can make better use of your server’s capacity. Instead of having a server dedicated to just one application, you can run multiple applications on the same server. This means your server is doing more work, which makes it more efficient.

Improve Performance

Virtualization can lead to better system performance. Since each virtual machine operates in its own environment, applications can run more smoothly.

Enhance Security

Virtualization can also boost your system’s security. Each virtual machine is isolated from the others, which means if one gets infected with a virus, the others remain safe.

Boost Scalability

Virtualization makes it easy to add new applications and servers as your business grows. You can quickly create a new virtual machine without buying new hardware.

Better Disaster Recovery

Virtualization can improve your disaster recovery efforts. It’s easier and faster to backup and restore virtual machines compared to physical servers.

Go Green

Virtualization is environmentally friendly. By reducing the number of physical servers, you’re using less energy, which is good for the planet.

KVM is a powerful open-source virtualization technology built into the Linux kernel. Essentially, it turns Linux into a hypervisor, allowing one computer to run multiple isolated operating systems simultaneously, known as guests or virtual machines.

Introduced in 2006 and integrated into the mainline Linux kernel by 2007, KVM comes standard with most Linux distributions. Each virtual machine functions like a regular Linux process, with dedicated virtual hardware such as a network card, graphics adapter, CPU(s), memory, and disks.

Working closely with QEMU, an open-source machine emulator, KVM enables running various operating systems and architectures. Being part of the Linux kernel means KVM automatically benefits from Linux updates, features, and security enhancements, like Security-Enhanced Linux (SELinux) and secure virtualization (sVirt), ensuring robust and secure virtual machine operation.

In summary, KVM offers a robust, efficient, and flexible solution for running multiple operating systems simultaneously on a single machine, making it a valuable tool in the virtualization landscape.

Explore Deeper into the World of Virtualization: KVM vs VMware

Are you intrigued by the differences and unique features of KVM and VMware? Don't stop here! Dive deeper to understand which virtualization solution best fits your needs. Click here for a comprehensive guide comparing KVM and VMware, covering everything from performance metrics to cost implications. Make an informed decision for your virtualization strategy today!

Learn More About KVM vs VMware

How Does KVM Work?

KVM, or Kernel-based Virtual Machine, works like a virtualization wizard for your computer. Imagine it as a magical spell that lets your computer act like many different computers at the same time.

Here's how it works in simple terms:

  1. Hypervisor Magic: KVM turns your regular Linux into a special hypervisor. A hypervisor is like a manager that makes sure your computer can run several separate operating systems, all isolated from each other.
  2. Virtual Machines (VMs): These are like make-believe computers created by KVM. Each one has its own pretend hardware, like a fake network card, fake graphics, and so on.
  3. Linux Process Trick: KVM uses a clever trick. It treats each virtual machine as if it's just a regular process on Linux. So, it's like running a bunch of normal programs, but each one thinks it's a whole computer.
  4. Buddy System with QEMU: KVM works closely with another friend called QEMU. QEMU helps KVM by pretending to be different types of computers and making sure they can run various operating systems.
  5. Linux Team Benefits: Since KVM is part of the Linux team, it automatically gets all the cool updates and improvements that Linux gets. This includes security features, making sure your pretend computers are safe and secure.
  1. Performance: KVM inherits the performance of Linux, scaling to match the demand load if the number of guest machines and requests increases. It allows the most demanding application workloads to be virtualized and is the basis for many enterprise virtualization setups, such as data centers and private clouds.
  2. Security: KVM uses a combination of security-enhanced Linux (SELinux) and secure virtualization (sVirt) for enhanced VM security and isolation. SELinux establishes security boundaries around VMs. sVirt extends SELinux’s capabilities, allowing Mandatory Access Control (MAC) security to be applied to guest VMs and preventing manual labeling errors.
  3. Storage: KVM can use any storage supported by Linux, including some local disks and network-attached storage.
  4. Hardware Support: KVM can use a wide variety of hardware. It supports hardware-assisted virtualization for a wide variety of guest operating systems including BSD, Solaris, Windows, Haiku, ReactOS, Plan 9, AROS, macOS, and even other Linux systems.

The KVM infrastructure consists of a kernel module that facilitates the creation and management of virtual machines. It relies on hardware virtualization extensions to streamline the virtualization process. These extensions, commonly found in contemporary processors, enable KVM to harness the full potential of hardware resources for optimal virtual machine performance. The integration with the Linux kernel ensures a seamless and efficient virtualization experience.

QEMU in the Mix

Working in tandem with KVM, QEMU (Quick Emulator) plays a pivotal role in the virtualization ecosystem. QEMU handles the emulation of devices and peripherals within the virtual machines, complementing KVM's capabilities. This collaboration ensures that virtualized environments created with KVM are equipped with the necessary emulated hardware components, facilitating compatibility with a wide range of guest operating systems.

Libvirt for Unified Management

Enter Libvirt, a powerful toolkit designed to simplify the management of various virtualization technologies, including KVM. Libvirt provides a unified and consistent interface for managing virtual machines, irrespective of the underlying hypervisor. With Libvirt, users can seamlessly interact with KVM through a standardized API, enabling them to create, configure, and manage virtual machines efficiently. This abstraction layer not only enhances ease of use but also fosters interoperability across different virtualization platforms.

Several tools have been developed to facilitate the management of KVM-based virtual machines, catering to users with diverse preferences. For those who prefer a graphical user interface, virt-manager offers an intuitive way to create and manage virtual machines. On the other hand, virsh provides a robust command-line interface (CLI) for users who favor the command line. Beyond these, solutions like oVirt and Proxmox offer extended management features, making them suitable for more complex virtualization setups.

In the next section, we'll delve into the performance benefits of KVM, exploring how its integration with hardware virtualization extensions contributes to impressive execution speeds for virtual machines. Additionally, we'll examine the security features embedded within KVM, ensuring the isolation and protection of virtualized environments.

Performance Benefits of KVM

One of the hallmarks of KVM virtualization lies in its exceptional performance. The seamless integration with hardware virtualization extensions, such as Intel VT-x and AMD-V, allows KVM to harness the full capabilities of modern processors. This hardware-level assistance offloads virtualization tasks, resulting in near-native performance for virtual machines. Whether you're running resource-intensive applications or a multitude of virtual instances, KVM ensures that your workloads operate with efficiency and speed.

Security Features

In the realm of virtualization, security is paramount, and KVM doesn't disappoint. The robust security features inherent in the Linux kernel, which serves as the foundation for KVM, provide a solid framework for creating secure virtualized environments. KVM enforces strict isolation between virtual machines, preventing potential security breaches and ensuring that each instance operates independently. The inherent security measures make KVM a reliable choice for enterprises and organizations with stringent security requirements.

Setting up KVM (Kernel-based Virtual Machine) is like preparing your computer to become a wizard at running multiple operating systems simultaneously. Here's a simple guide:

1. Check Compatibility

Before diving in, make sure your computer supports virtualization. Most modern computers do, but it's good to double-check in the computer's BIOS settings.

2. Install Linux

Since KVM is part of the Linux family, you need a Linux-based operating system. Choose and install a Linux distribution of your choice. Popular ones include Ubuntu, Fedora, and CentOS.

3. Check KVM Support

Ensure that your Linux installation supports KVM. You can do this by running a command like:

   grep -E 'svm|vmx' /proc/cpuinfo

If you see some output, great! It means your CPU supports virtualization.

4. Install KVM Packages

Use your Linux distribution's package manager to install the necessary KVM packages. For example, on Ubuntu, you can use:

   sudo apt-get install qemu-kvm libvirt-bin virtinst

5. Start KVM Services

Once installed, start the KVM-related services. On most systems, you can use:

   sudo systemctl start libvirtd

   sudo systemctl enable libvirtd

6. Verify Installation

Check if KVM is working by running a command like:

   virsh list --all

It should show an empty list if there are no virtual machines yet.

7. Set Up Virtual Machines (VMs)

Now that KVM is ready, you can create and configure virtual machines. You can use tools like Virt-Manager (a graphical tool) or virsh (command-line) to create and manage VMs.

8. Install Operating Systems on VMs

Just like you install an operating system on a regular computer, install the desired operating systems on your virtual machines. This could be Linux, Windows, or any other supported OS.

9. Enjoy Your Virtual World

Once everything is set up, you're ready to go! Start your virtual machines and enjoy the flexibility of running multiple operating systems on a single computer.

As we uncover the layers of KVM virtualization, it's essential to highlight its prevalence in real-world applications. KVM has found a home in diverse industries, including data centers and cloud environments, where the ability to efficiently manage and scale virtualized resources is crucial. Its open-source nature and robust performance make KVM a preferred choice for businesses seeking a reliable and flexible virtualization solution.

Open Source Nature

KVM's open-source nature is a significant advantage, fostering collaboration, community contributions, and continuous improvement. The transparency of the source code allows users to understand the inner workings of the technology, contribute enhancements, and address potential issues. This collaborative approach has contributed to the widespread adoption of KVM, making it a staple in the virtualization landscape.

In this exploration of KVM virtualization, we've peeled back the layers to reveal a powerful and versatile technology deeply integrated into the Linux ecosystem. KVM, standing for Kernel-based Virtual Machine, has proven itself as a go-to solution for creating and managing virtual environments on Linux-based systems.

From understanding the fundamental components of KVM to exploring its integration with QEMU and Libvirt, we've seen how this technology offers a holistic approach to virtualization. The management tools, both graphical and command-line, provide users with flexibility and ease of use, while the performance benefits, driven by hardware virtualization extensions, ensure that virtual machines operate at near-native speeds.

Security, a paramount concern in virtualized environments, is addressed through the inherent measures within the Linux kernel. KVM's strict isolation between virtual machines safeguards against potential security threats, making it a trusted choice for environments with high-security requirements.

Real-world applications have showcased KVM's adaptability, finding a home in data centers and cloud infrastructures. Its open-source nature has fostered a vibrant community, contributing to its continual improvement and widespread adoption.

As we conclude our journey into the world of KVM, remember that the realm of virtualization is dynamic, and KVM stands as a testament to the collaborative and innovative spirit of open-source technologies. Whether you're a system administrator, developer, or enthusiast, KVM provides a robust foundation for your virtualization endeavors.

KVM, or Kernel-based Virtual Machine, is a feature in Linux that allows your computer to run multiple operating systems at the same time. It’s like having multiple computers inside your single computer, each running its own system independently.

KVM offers several features such as high performance, strong security, flexible storage options, and wide hardware support.

Yes, KVM is open-source, which means it’s free to use and has a large community of developers continually improving it.

Yes, KVM can run a variety of guest operating systems, including Windows, BSD, Solaris, macOS, and even other Linux systems.

Lisa P

Lisa P

Hello, everyone, my name is Lisa. I'm a passionate electrical engineering student with a keen interest in technology. I'm fascinated by the intersection of engineering principles and technological advancements, and I'm eager to contribute to the field by applying my knowledge and skills to solve real-world problems.