Kernel-based Virtual Machine (KVM) is an open-source virtualization technology that allows for full virtualization of hardware resources on Linux operating systems. It is integrated into the Linux kernel and provides a powerful platform for running multiple virtual machines (VMs) with various operating systems on a single physical host. Here’s an overview of KVM and its key features:
1. Hypervisor Architecture: KVM is a Type 1 or bare-metal hypervisor, which means it runs directly on the host hardware without the need for a host operating system. It leverages the Linux kernel’s virtualization capabilities to provide virtual machine management.
2. Hardware Virtualization Support: KVM utilizes hardware virtualization extensions, such as Intel VT-x (for Intel processors) and AMD-V (for AMD processors), to enhance performance and efficiency. These extensions enable direct execution of guest operating systems, reducing the overhead of software emulation.
3. Full Virtualization: KVM allows for full virtualization of hardware resources, enabling VMs to run unmodified operating systems. It supports a wide range of guest operating systems, including various Linux distributions, Windows, BSD, and more.
4. CPU and Memory Management: KVM provides CPU and memory management capabilities, allowing administrators to allocate CPU cores, set resource limits, and adjust memory allocation for each VM. This ensures efficient resource utilization and optimal performance.
5. Device Emulation and Passthrough: KVM supports device emulation for common hardware components, enabling VMs to interact with emulated devices. It also allows for device passthrough, where physical devices can be directly assigned to specific VMs, providing near-native performance.
6. Live Migration: KVM supports live migration, allowing VMs to be moved between physical hosts without interrupting their operation. This enables workload balancing, hardware maintenance, and high availability.
7. Linux Integration: KVM is tightly integrated with the Linux kernel and leverages various Linux features, such as the scheduler, memory management, and security mechanisms. This integration ensures efficient and secure virtualization performance.
8. Management Tools: KVM is commonly managed using tools like libvirt and virt-manager. These tools provide graphical interfaces and command-line utilities for creating, configuring, and managing VMs, as well as monitoring their performance.
9. Open-Source and Community Support: KVM is an open-source project, which means it benefits from continuous community contributions, improvements, and bug fixes. This active community support ensures ongoing development, stability, and security of the KVM virtualization technology.
KVM is widely adopted in the Linux ecosystem and is used by individuals, organizations, and cloud providers for server virtualization, consolidation, and cloud computing deployments. Its flexibility, performance, and open-source nature make it a popular choice for running virtual machines on Linux-based systems.