KVM in action
Kernel-based virtual machine (KVM) technology is the most recent step in the evolution of open source, x86 virtualization technology. KVM turns the Linux kernel into a bare-metal hypervisor using the hardware virtualization support built into Intel and AMD processors. This means that KVM can use Linux to do many of the things that a hypervisor needs to do, like scheduling tasks, managing memory and interacting with hardware devices.
KVM creates virtual machines as Linux processes which can then run either Linux or Windows as a guest operating system, and using a modified version of another open source module – QEMU – to provide I/O device emulation inside the virtual machine. KVM is thus able to efficiently and effectively run both Windows and Linux workloads in virtual machines – and also Linux applications natively alongside if required.
The Linux Advantage
By leveraging Linux for core functions, KVM is able to avoid reinventing the wheel – taking advantage of the performance, scalability and security already built into Linux, which has been enterprise hardened for over 10 years and is trusted by millions of organizations in the heart of their data center to run their mission critical workloads. This gives KVM a significant "feature velocity" that other virtualization solutions cannot match. KVM has also brought new features to the Linux kernel including kernel page sharing (KSM), transparent large page support, and a new user-mode device driver infrastructure. Based on Linux, KVM is designed to be cost-effective and efficient and avoids vendor "lock in" giving you the virtualization capabilities you need.
All choice, no vendor-lock in
Organizations demand choice that helps avoid expensive lock-in to proprietary virtualization technologies.
KVM – the open source alternative provides - a smarter choice.
Lower cost of ownership
As it is open source and available in existing Linux Distributions today, KVM is cost-effective. Analysis shows that KVM is 39% cheaper over a 3-year TCO compared to competition*
*Source: Red Hat Enterprise Virtualization for Servers: Competitive pricing guide, 2010
Enterprise Class Performance
In recent SPECvirt benchmarks KVM demonstrated the highest performance benchmarks and the highest number of performant virtual machines running on a single host. KVM on IBM hardware published 94% better virtual machine consolidation capability than the nearest competitor utilizing VMware*
*Source: SpecVirt_sc2010 results: http://www.spec.org/virt_sc2010/results/
SELinux enables KVM to provide Mandatory Access Control security between virtual machines. This allows Cloud providers with multiple tenants or customers to provide advanced security protection on a “need-to-know” basis between virtual machines. With KVM, security-conscious organizations can create secure, open virtualization IT environments and private clouds, and save money on virtualization security tools. KVM meets government security standards through Common Criteria Certification at Evaluation Assurance Level 4+ (EAL4+). Learn more here.
How do you get KVM?
There’s two main ways of getting KVM.
1. As part of a Linux distribution (shown as everything inside the blue box)
Many Linux distributions already come with KVM as part of the package, including Red Hat Enterprise Linux, SUSE Linux Enterprise Server, and Canonical Ubuntu.
This approach would typically be used for virtualizing servers running Linux or mixed Linux/Windows workloads.
- Red Hat Enterprise Linux 5.4 and above
- SUSE Linux Enterprise Server 11 SP1 and above
- Canonical Ubuntu 10.04 LTS and above
2. As a standalone hypervisor (shown as everything inside the red box)
Here the KVM / Linux combination has been optimized and stripped down to leave just the modules needed to deliver a hypervisor. Red Hat Enterprise Virtualization is an example of this approach, which is often used for clouds or for virtualizing servers running Windows or server farms comprising both Windows and Linux servers
- Red Hat Enterprise Virtualization – H 2.2 and above