What is KVM? Why It’s the Best Choice for Virtualization

what is kvm

KVM (Kernel-based Virtual Machine) is an open-source solution for enabling virtualization technology for Linux. In today’s ever-changing tech landscape, virtualization has become a cornerstone of efficient resource utilization and flexible infrastructure management. Among the various virtualization technologies available, a Kernel-based Virtual Machine stands out as a powerful, functional and versatile solution. 

In this blog, we will discuss What is KVM, How it works, why KVM, and What are its features.

What is KVM?

KVM is a virtualization solution that lets VPS function as a fully independent server. It is a type of hypervisor that allows you to run multiple virtual machines on a single physical server. Unlike some other hypervisors, KVM is integrated directly into the Linux kernel. 

This integration provides significant performance advantages and improves features of the Linux operating system. 

This virtualization setup contains a kernel module named Kvm.ko and a module-specific processor Kvm.intel.ko and Kvm-amd.ko. The selection among processor-specific modules is based on the type of processor hardware being used to run the machine. 

How KVM works & its architecture

KVM needs Linux Kernel installation on a computer by a CPU that supports virtualization extension. Its architecture is efficient. It maximizes the existing Linux kernel’s capabilities, it doesn’t require a separate, dedicated hypervisor operating system. Here’s a breakdown:

  • Linux KernelLinux Kernel is the foundation of KVM. A kernel is a low-level program that engages with computer hardware. It is the core of the open-source operating system. 

It makes sure that the software applications running on the operating system get needed computing resources. The Linux kernel is included in distributions such as Red Hat Enterprise Linux (RHEL), Fedora, and Ubuntu. 

  • KVM Module – This module offers core virtualization infrastructure. Which expose the necessary interfaces for creating and managing VMs. The core part of KVM is directly integrated into the Linux kernel as Kvm.ko. These modules leverage hardware virtualization extensions for better performance. 
  • QEMU – Quick Emulator or QEMU is often used in conjunction with KVM. QEMU works as a user-space process, while KVM looks after the virtualization at the kernel level. It offers emulation layers for the hardware like network adapters, storage controllers and more. Guest VMs interact with these hardwares. 
  • Guest VMs – Guest Virtual Machines is an isolated virtual environment that functions on a physical host system using virtualization softwares. These Guest VMs operate as if it is a separate physical machine with their own separate physical machine.

This architecture of KVM functions to benefit from the stability, security, and extensive feature set of the Linux kernel.

Why choose KVM for virtualization

KVM converts Linux kernel into a bare-metal hypervisor, enabling it to direct and provide resources like CPU, memory, and storage to the guest VMs. This approach of great resource allocation enhances functionality.

Here are some key advantages that contribute to KVM’s popularity:

High Performance

Being integrated into the kernel, KVM VPS delivers high performance. VMs operating on KVM experience minimal overhead, making it convenient for even demanding applications.

Open Source & Cost-Effective

KVM is open-source, which means there are no licensing charges. This makes it a cost-effective solution, especially for smaller businesses or individuals.

Security 

KVM adopts the security features of the Linux kernel, helping from its robust security model and regular updates.

Flexibility

KVM supports various guest operating systems, including Linux, Windows, and others. It also offers a high degree of flexibility regarding resource allocation and customization.

Feature-Rich

KVM offers a comprehensive set of virtualization features, including live migration, dynamic resource allocation, and support for various storage and networking options.

Key Features of KVM 

Here are key features of using Kernel based virtual machine 

  1. Full Virtualization Assistance:

KVM supports full virtualization, allowing various, isolated virtual machines (VMs) to function on a single physical host along with numerous operating systems, comprising Linux, Windows, and others.

  1. Kernel Integration:

Since KVM is part of the Linux kernel, it benefits from the kernel’s performance, security and stability functions. It transforms Linux into a Type 1 (bare-metal) hypervisor while operating as a Type 2 hypervisor within the OS.

  1. Hardware-Assisted Virtualization:

KVM leverages hardware virtualization extensions like Intel VT-x and AMD-V for scalable performance and efficiency, reducing overhead compared to software-based virtualization.  It supports large scale deployments and it is capable of managing multiple virtual CPUs and large amounts of RAM per Virtual Machine.

4. Resource Management:

Kernel-based Virtual Machine offers fine-grained control over resource allocation, including CPU, memory, storage, and network interfaces. Administrators can dynamically adjust these resources based on workload demands and needs.

In conclusion, throughout the years KVM has emerged as a leading virtualization technology due to its performance, open-source nature, security, and flexibility advantages. Its tight integration with the Linux kernel provides significant plus points, making it a strong contender for a wide range of virtualization needs, from small deployments to large-scale cloud infrastructures. If you’re looking for a robust and cost-effective virtualization solution, KVM is the best solution for you.

FAQ’s

1. Who invented KVM?
Avi Kivity, invented the Kernel-based Virtual Machine (KVM) in 2006. 

2. What operating systems can I use with KVM?
You can run various operating systems with KVM such as Linux, Windows, BSD, Solaris, and even macOS. You use them as both host and guest.

3. Can I perform live migration with KVM?
Yes, KVM supports live migration, it allows you to move running VMs from one physical host to another without any downtime.

4. What are the hardware requirements for KVM?
Hardware requirements of KVM include a processor with virtualization extensions and a Linux-based OS with KVM kernel modules installed. 

5. What tools can I use to manage KVM?
Libvirt, Virt-Manager, Virsh, QEMU and OpenStack are popular tools to manage KVM. 

6. What storage options does KVM support?
KVM supports various storage options such as local disk, LVM, NFS, iSCSI, Ceph and more. It also allows snapshots, thin provisioning, and dynamic disk resizing.

7. KVM VS VirtualBox
KVM is a high-performance hypervisor integrated in the Linux kernel. It is ideal for scalable and enterprise-level environments like cloud computing. While VirtualBox is a cross-platform providing user-friendly interface. 

KVM provides better performance, On the other hand VirtualBox is more accessible for casual users and smaller-scale setups.