Log in to your Red Hat account
Your Red Hat account gives you access to your member profile and preferences, and the following services based on your customer status:
Not registered yet? Here are a few reasons why you should be:
- Browse Knowledgebase articles, manage support cases and subscriptions, download updates, and more from one place.
- View users in your organization, and edit their account information, preferences, and permissions.
- Manage your Red Hat certifications, view exam history, and download certification-related logos and documents.
Your Red Hat account gives you access to your member profile, preferences, and other services depending on your customer status.
For your security, if you're on a public computer and have finished using your Red Hat services, please be sure to log out.Log out
What is KVM?
Kernel-based Virtual Machine (KVM) is an open source virtualization technology built into Linux庐. 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鈥檝e got Linux 2.6.20 or newer, you鈥檝e 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鈥攕uch as a memory manager, process scheduler, input/output (I/O) stack, device drivers, security manager, a network stack, and more鈥攖o run VMs. KVM has all these components because it鈥檚 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.
But implementing KVM on a supported Linux distribution鈥攍ike Red Hat Enterprise Linux鈥攅xpands KVM's capabilities, letting you swap resources among guests, share common libraries, optimize system performance, and a lot more.
Migrating to a KVM-based virtual infrastructure
Building a virtual infrastructure on a platform you鈥檙e contractually tied to may limit your access to the source code. That means your IT developments are probably going to be more workarounds than innovations, and the next contract could keep you from investing in clouds, containers, and automation. Migrating to a KVM-based virtualization platform means being able to inspect, modify, and enhance the source code behind your hypervisor. And there鈥檚 no enterprise-license agreement because there鈥檚 no source code to protect. It鈥檚 yours.
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鈥檚 preferred hypervisor.
KVM uses a combination of security-enhanced Linux (SELinux) and secure virtualization (sVirt) for enhanced VM security and isolation. SELinux establishes security boundaries around VMs. sVirt extends SELinux鈥檚 capabilities, allowing Mandatory Access Control (MAC) security to be applied to guest VMs and preventing manual labeling errors.
KVM is able to use any storage supported by Linux, including some local disks and network-attached storage (NAS). Multipath I/O may be used to improve storage and provide redundancy. KVM also supports shared file systems so VM images may be shared by multiple hosts. Disk images support thin provisioning, allocating storage on demand rather than all up front.
KVM can use a wide variety of certified Linux-supported hardware platforms. Because hardware vendors regularly contribute to kernel development, the latest hardware features are often rapidly adopted in the Linux kernel.
KVM inherits the memory management features of Linux, including non-uniform memory access and kernel same-page merging. The memory of a VM can be swapped, backed by large volumes for better performance, and shared or backed by a disk file.
KVM supports live migration, which is the ability to move a running VM between physical hosts with no service interruption. The VM remains powered on, network connections remain active, and applications continue to run while the VM is relocated. KVM also saves a VM's current state so it can be stored and resumed later.
KVM inherits the performance of Linux, scaling to match demand load if the number of guest machines and requests increases. KVM allows the most demanding application workloads to be virtualized and is the basis for many enterprise virtualization setups, such as datacenters and private clouds (via OpenStack庐).
In the KVM model, a VM is a Linux process, scheduled and managed by the kernel. The Linux scheduler allows fine-grained control of the resources allocated to a Linux process and guarantees a quality of service for a particular process. In KVM, this includes the completely fair scheduler, control groups, network name spaces, and real-time extensions.
The Linux kernel features real-time extensions that allow VM-based apps to run at lower latency with better prioritization (compared to bare metal). The kernel also divides processes that require long computing times into smaller components, which are then scheduled and processed accordingly.
It鈥檚 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鈥檚 the sole hypervisor for all of our virtualization products, and we鈥檙e continually improving the kernel code with contributions to the KVM community. But since KVM is part of Linux, it鈥檚 already included in Red Hat Enterprise Linux鈥攕o 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鈥檚 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鈥檇 like to 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.
The OpenStack word mark and the Square O Design, together or apart, are trademarks or registered trademarks of OpenStack Foundation in the United States and other countries, and are used with the OpenStack Foundation鈥檚 permission. Red Hat, Inc. is not affiliated with, endorsed by, or sponsored by the OpenStack Foundation or the OpenStack community.