KVM

KVM, short for Kernel-based Virtual Machine, is a full virtualization solution built directly into the Linux kernel. It lets you run multiple virtual machines running unmodified Linux or Windows images by leveraging the hardware virtualization extensions of modern CPUs, such as Intel VT-x and AMD-V. Each VM is implemented as a regular Linux process, scheduled by the kernel's standard scheduler, which gives it excellent performance and resource management. KVM itself provides only the core virtualization infrastructure. To actually manage and create VMs, you pair it with a user-space tool like QEMU, which handles device emulation, or use libvirt and virt-manager for a more polished management interface. It supports a wide range of guest operating systems, paravirtualized drivers via virtio for faster I/O, live migration, and even nested virtualization. KVM is the foundation for many commercial and open source virtualization platforms, including Red Hat Virtualization and OpenStack. It has been part of the mainline Linux kernel since 2007 and is maintained by the open source community with backing from Red Hat and other companies. If you are running Linux and need to spin up VMs without a heavy proprietary hypervisor, KVM is the most direct route.