What is KVM?
Kernel-based Virtual Machine (KVM) is an open source virtualization technology built into Linux®. Specifically, KVM lets you turn Linux into a hypervisor that allows a host machine to run multiple, isolated virtual environments called guests or virtual machines (VMs).
KVM is part of Linux. If you’ve got Linux 2.6.20 or newer, you’ve got KVM. KVM was first announced in 2006 and merged into the mainline Linux kernel version a year later. Because KVM is part of existing Linux code, it immediately benefits from every new Linux feature, fix, and advancement without additional engineering.
How does KVM work?
KVM converts Linux into a type-1 (bare-metal) hypervisor. All hypervisors need some operating system-level components—such as a memory manager, process scheduler, input/output (I/O) stack, device drivers, security manager, a network stack, and more—to run VMs. KVM has all these components because it’s part of the Linux kernel. Every VM is implemented 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.
Long story short, you have to run a version of Linux that was released after 2007 and it needs to be installed on X86 hardware that supports virtualization capabilities. If both of those boxes are checked, then all you have to do is load 2 existing modules (a host kernel module and a processor-specific module), an emulator, and any drivers that will help you run additional systems.
KVM is part of Linux. Linux is part of KVM. Everything Linux has, KVM has too. But there are specific features that make KVM an enterprise’s preferred hypervisor.
It’s possible to manually manage a handful of VM fired up on a single workstation without a management tool. Large enterprises use virtualization management software that interfaces with virtual environments and the underlying physical hardware to simplify resource administration, enhance data analyses, and streamline operations. Red Hat created Red Hat Virtualization for exactly this purpose.
KVM and Red Hat
We believe in KVM so much that it’s the sole hypervisor for all of our virtualization products, and we’re continually improving the kernel code with contributions to the KVM community. But since KVM is part of Linux, it’s already included in Red Hat Enterprise Linux—so why would you want Red Hat Virtualization?
Well, Red Hat has 2 versions of KVM. The KVM that ships with Red Hat Enterprise Linux has all of the hypervisor functionality with basic management capabilities, allowing customers to run up to 4 isolated virtual machines on a single host. Red Hat Virtualization contains an advanced version of KVM that enables enterprise management of unlimited guest machines. It’s ideal for use in datacenter virtualization, technical workstations, private clouds, and in development or production.
Do you have a legacy app that requires an older operating system? Perhaps you’d like pilot a new app in a low-risk environment? You can configure Red Hat Enterprise Linux as a basic hypervisor for running up to 4 isolated VM on a single host.
This is all you need. Really. Install it on anything—from bare-metal hardware to open source or proprietary systems—and start deploying virtual machines by the dozens or hundreds with an advanced hypervisor that can handle it and a management platform that makes it easy.
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