Virtualization technology has revolutionized the way we deploy applications, manage data centers, and utilize hardware resources. Among the various virtualization solutions available, Kernel-based Virtual Machine (KVM) stands out as a robust and efficient option for Linux users. This foundational article aims to demystify KVM virtualization, explaining its workings, advantages, and the requirements for running it effectively. Additionally, we will discuss the types of workloads it’s best suited for and provide practical examples to get started.

What is KVM?

KVM (Kernel-based Virtual Machine) is an open-source virtualization technology built into Linux. It lets you turn Linux into a hypervisor that allows a host machine to run multiple, isolated virtual environments called virtual machines (VMs) or guests. KVM converts Linux into a Type-1 (bare-metal) hypervisor. It requires the processor on the host machine to support hardware virtualization extensions (Intel VT or AMD-V).

How KVM Works

KVM works by loading a kernel module (kvm.ko) that provides the core virtualization infrastructure, and a processor-specific module (kvm-intel.ko or kvm-amd.ko). Once loaded, these modules allow Linux to function as a hypervisor that can host multiple VMs, each running its own independent operating system.

KVM leverages the existing Linux kernel functionalities such as scheduling and memory management, allowing VMs to operate using Linux kernel’s native devices and drivers. This integration results in efficient and high-performance virtualization that is deeply integrated with the Linux ecosystem.

Advantages of KVM

• Performance: Thanks to its integration with the Linux kernel and support for latest hardware-assisted virtualization technologies, KVM offers near-native performance for VMs.
• Scalability: KVM’s scalability is limited only by the hardware’s capabilities, making it suitable for both small and large deployments.
• Security: Leveraging SELinux (Security-Enhanced Linux), KVM benefits from powerful mandatory access control (MAC), ensuring strong isolation between VMs.
• Cost-Efficient: Being open-source and part of the Linux kernel, KVM is a cost-effective virtualization solution for businesses and individuals alike.

Requirements for Running KVM

• Hardware: A processor with support for hardware virtualization extensions (Intel VT-x or AMD-V).
• Kernel: A Linux kernel version 2.6.20 or higher, with KVM modules included.
• Software: QEMU for emulating hardware, libvirt for managing VMs through a unified interface, and virt-manager as a graphical tool for managing VMs.

Best Suited Workloads

KVM is incredibly versatile, making it suitable for a wide range of workloads:

• Development and Testing: Quickly spin up or tear down development and testing environments with isolated dependencies.
• Server Consolidation: Reduce hardware costs by consolidating multiple server roles on a single physical machine.
• Cloud Computing: Power the backbone of cloud services with the ability to host a large number of VMs efficiently.
• Desktop Virtualization: Run multiple operating systems on a single desktop for software testing or cross-platform development.

Getting Started with KVM

Installing KVM

Check if your system supports hardware virtualization:

egrep -c '(vmx|svm)' /proc/cpuinfo

If the output is greater than 0, your system supports hardware virtualization. Next, install KVM and its components:

On Ubuntu/Debian:

sudo apt update && sudo apt install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils virt-manager

On CentOS/RHEL:

sudo yum install qemu-kvm libvirt libvirt-python libguestfs-tools virt-install

Creating Your First VM

Use virt-install to create a new VM:

sudo virt-install \
--name=TestVM \
--ram=2048 \
--vcpus=2 \
--disk path=/var/lib/libvirt/images/TestVM.img,size=20 \
--os-type=linux \
--os-variant=generic \
--network bridge=virbr0 \
--graphics none \
--console pty,target_type=serial \
--location='http://releases.ubuntu.com/18.04/ubuntu-18.04.4-server-amd64.iso' \
--extra-args='console=ttyS0'

This command creates a VM named TestVM, with 2 GB of RAM, 2 CPU cores, a 20 GB disk, and installs Ubuntu 18.04 from an ISO image.

Conclusion

KVM virtualization offers a potent, efficient, and scalable solution for managing virtual machines on Linux. Its integration with the Linux kernel, coupled with support for the latest virtualization technologies, makes it an ideal choice for a wide range of applications, from development and testing to large-scale cloud computing.

For those looking for a reliable and high-performance Cloud VPS solution, Shape.host services offer Linux SSD VPS powered by KVM virtualization, ensuring top-notch performance and reliability for your virtualized environments.

Incorporating KVM into your virtualization strategy can significantly enhance your capability to deploy, manage, and scale virtualized resources efficiently and cost-effectively.

Consider Shape.host’s Cloud VPS services for your KVM virtualization needs, and leverage our expertise to power your virtualization projects.

Written by Chatsonic