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Kernel-Based Virtual Machine

Definition

Kernel-Based Virtual Machine (KVM) is a virtualization technology built into Linux that essentially turns it into a hypervisor, which can run multiple, isolated virtual environments called virtual machines. KVM allows the kernel to function as a middleman between the hardware and the virtualized systems, managing system resources like CPU, memory, and disk. It enables users to load multiple guest operating systems with distinct sets of applications as if they were separate computers.

Phonetic

KUR-nel-BAYST VIR-choo-al ma-SHEEN

Key Takeaways

<ol><li>Kernel-Based Virtual Machine (KVM) is a full virtualization solution for Linux on hardware containing virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module that provides the core virtualization infrastructure and a processor-specific module.</li><li>KVM requires a modified QEMU although work is underway to get the required changes upstream. Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has private virtualized hardware: a network card, disk, graphics adapter, etc.</li><li>KVM is part of Linux. If you have a recent Linux kernel and you’re running on x86 hardware with virtualization extensions, you wouldn’t need anything else to use KVM—it’s already included in your Linux kernel.</li></ol>

Importance

Kernel-Based Virtual Machine (KVM) is a critical technology term in the realm of virtualization for its unique functionality in bridging the physical and virtual worlds. KVM is an open-source full virtualization solution for Linux on hardware containing virtualization extensions such as Intel VT or AMD-V. It consists of a loadable kernel module, which offers the core virtualization infrastructure, and a processor-specific module. Of significance is the fact that KVM turns the Linux kernel into a hypervisor, thereby enabling the host machine to run multiple, isolated virtual environments, called “guests”. This integration into the Linux kernel enhances performance, as it leverages in-built kernel features and allows direct interaction with the hardware, resulting in an efficient and productive use of resources. Hence, the importance of KVM stems from its ability to create secure, scalable virtualized environments, maximizing both performance and hardware utilization.

Explanation

Kernel-Based Virtual Machine, often abbreviated as KVM, is a foundational technology used to enable and manage virtualization, a strategy that allows multiple, disparate systems to share the resources of one physical host machine. This means, in essence, that a single computer’s hardware can be divided up to independently support multiple “virtual” machines, each running their own operating systems and applications. This drastically increases the efficiency of resource use, as the host’s processing power, memory, and storage are not tied to any single task or function, but freely allocated across a number of virtual systems as required.The key benefit and purpose of KVM is that it allows these virtual environments to run side-by-side on a single piece of hardware while ensuring they’re entirely isolated from one another. This means, despite sharing the same physical resources, what happens in one virtual machine (such as a crash or a virus attack) doesn’t affect the others. It also allows administrators to bring up and tear down virtual servers on demand, making it easier to scale systems in response to need. These features make KVM an incredibly valuable tool in a variety of use cases, but particularly in server management, data centers, and cloud computing.

Examples

1. Hosting services: Many hosting services use Kernel-Based Virtual Machines (KVMs) to allow their customers to run their own virtual servers. For instance, services like DigitalOcean and Linode utilize KVM technology to enable users to deploy multiple operating systems on the same hardware, optimizing resource usage.2. Corporate IT environments: Many corporations use KVMs in their IT environments for server isolation and security. By using KVMs, IT teams can run different software or applications on the same server without them interfering with each other, increasing both security and efficiency.3. Software testing and development: Developers often use KVMs to create controlled environments for software testing. By using KVM technology, they can simulate different operating systems and configurations on the same machine, which helps to ensure that the software will function correctly in various environments.

Frequently Asked Questions(FAQ)

Q: What is a Kernel-Based Virtual Machine (KVM)? A: The Kernel-Based Virtual Machine, or KVM, is a full virtualization solution for Linux on hardware containing virtualization extensions. It is a tool that allows a Linux machine to host multiple instances of Linux or Windows operating systems simultaneously. Q: What are the system requirements for using a KVM? A: To use KVM, you need a processor that supports hardware virtualization. Intel and AMD both offer hardware virtualization support. Additionally, your system will need to have a Linux kernel on it that supports KVM. Q: How does KVM differ from other virtualization tools? A: KVM differs from other virtualization tools because it is integrated into the standard Linux kernel, making it more efficient and easy to maintain. This helps with performance and lets KVM utilize existing Linux features.Q: How much does it cost to use KVM?A: KVM is open-source, which means it’s free to use. However, there can be costs involved in setting up and managing the servers that host your KVM machines, depending on your specific needs.Q: Will applications run differently on a KVM virtual machine compared to running on a physical machine? A: For the most part, applications should run the same on a KVM virtual machine as they do on a physical machine. Performance will largely depend on your allocated resources.Q: Can you run multiple operating systems on KVM? A: Yes, you can run multiple operating systems on KVM, including different versions of Linux and Windows.Q: Can I use KVM if I don’t know Linux? A: While KVM is designed to work best with Linux, there are user interfaces and management tools available to help those unfamiliar with Linux. Understanding some basic Linux commands, however, would be beneficial.Q: How does KVM handle system resources? A: KVM handles system resources by distributing the available resources from the host machine across the different virtual machines. You can manually assign specific resources to each virtual machine.

Related Tech Terms

  • Hyper-V
  • Virtualization
  • QEMU
  • Guest Operating System
  • Host Machine

Sources for More Information

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