What is KVM?

Kernel-based Virtual Machine (KVM) is an open-source virtualization technology integrated into the Linux kernel. It transforms the Linux kernel into a bare-metal hypervisor, enabling it to run multiple virtual machines (VMs) simultaneously on a single physical host. Each virtual machine operates as an independent entity with its own virtualized hardware, including CPU, memory, storage and network interfaces.

Kernel-based Virtual Machine was introduced by Avi Kivity in 2006 at Qumranet and was merged into the Linux kernel mainline in version 2.6.20, released in February 2007. Since then, it has become a fundamental component of Linux-based virtualization solutions.

How Does KVM Work?

Kernel-based Virtual Machine leverages hardware virtualization extensions provided by modern processors such as Intel VT-x and AMD-V. These extensions allow Kernel-based Virtual Machine to run guest operating systems directly on the host hardware without the need for binary translation or emulation, resulting in near-native performance.

The architecture of Kernel-based Virtual Machine includes:

• Kernel Module (kvm.ko): This module provides the core virtualization infrastructure within the Linux kernel.
• Processor-Specific Modules (kvm-intel.ko or kvm-amd.ko): These modules enable support for Intel or AMD processors, respectively.
• User-Space Tools: Tools like QEMU (Quick Emulator) and libvirt provide the necessary interfaces to manage and interact with virtual machines.

When a virtual machine is created, Kernel-based Virtual Machine allocates virtual resources and manages the execution of the guest operating system. The guest operating system operates as a regular Linux process, scheduled by the standard Linux scheduler, with dedicated virtual hardware like a network card, graphics adapter, CPU(s), memory and disks.

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Key Features of KVM

Here are some of the key features of Kernel-based Virtual Machines.

Performance:

Kernel-based Virtual Machine provides near-native performance for virtualized workloads, thanks to its hardware-assisted virtualization and low overhead. This makes Kernel-based Virtual Machine ideal for running resource-intensive applications such as databases, web servers and virtual desktops.

Security:

Virtual machines running on KVM benefit from native security features like Security-Enhanced Linux (SELinux), ensuring strict adherence to security boundaries for enhanced data privacy and governance.

Flexibility:

Kernel-based Virtual Machine supports a wide range of guest operating systems including various Linux distributions, Windows, BSD and others. This flexibility allows organizations to run diverse workloads on a single platform.

Live Migration:

Kernel-based Virtual Machine supports live migration, enabling the movement of running virtual machines between physical hosts without downtime. This capability is crucial for load balancing and maintenance operations.

Scalability:

Kernel-based Virtual Machine can scale to meet the demands of large enterprise environments, supporting thousands of virtual machines on a single host, depending on the underlying hardware.

Cost-Effectiveness:

As an open-source technology, KVM eliminates licensing fees associated with proprietary hypervisors, making it a cost-effective solution for organizations.

Why Choose KVM?

Kernel-based Virtual Machines popularity can be attributed to several factors:

• Integration with Linux Ecosystem:

Being part of the Linux kernel, Kernel-based Virtual Machines benefits from the stability, security and performance of the Linux operating system.

• Community Support:

Kernel-based Virtual Machines is supported by a large and active open-source community, ensuring continuous development, support and innovation.

• Adoption by Cloud Providers:

Major cloud providers including Amazon Web Services (AWS) and Google Cloud, utilize Kernel-based Virtual Machines as the foundation for their virtualization platforms. AWS’s Nitro Hypervisor and Google Cloud’s Compute Engine are built upon Kernel-based Virtual Machines, leveraging its performance and scalability.

• Enterprise Adoption:

Many enterprises have adopted Kernel-based Virtual Machines for their virtualization needs due to its reliability, performance and cost-effectiveness.

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Getting Started with KVM

To deploy Kernel-based Virtual Machines, the following steps are typically involved:

Hardware Requirements:

Ensure the host system has a processor with hardware virtualization support (Intel VT-x or AMD-V) and sufficient resources (CPU, memory, storage) to run multiple virtual machines.

Install Linux Distribution:

Choose a Linux distribution that supports Kernel-based Virtual Machines such as Red Hat Enterprise Linux, CentOS or Ubuntu.

Install KVM Packages:

Install the necessary KVM packages, including the kernel modules, QEMU and libvirt.

Create Virtual Machines:

Use tools like virt-manager or virsh to create and manage virtual machines.

Configure Networking and Storage:

Set up virtual networks and storage pools to support the virtual machines.

Monitor and Manage:

Utilize monitoring tools to oversee the performance and health of the virtual machines and host system.

Conclusion

Kernel-based Virtual Machines has emerged as a leading virtualization technology, offering a powerful, secure and cost-effective solution for running multiple virtual machines on a single physical host. Its integration with the Linux kernel, support for hardware virtualization and active community make it an attractive choice for organizations seeking to optimize their IT infrastructure. Whether you are a cloud provider, enterprise or individual user, Kernel-based Virtual Machines provides the tools and capabilities needed to meet your virtualization needs.

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