KVM

Introduction
KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko.

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.

KVM is open source software. The kernel component of KVM is included in mainline Linux, as of 2.6.20. The userspace component of KVM is included in mainline QEMU, as of 1.3.

Install
sudo apt-get install qemu-kvm libvirt-bin ubuntu-vm-builder bridge-utils virt-manager

Guest Agent
ssh user@guest sudo apt-get install qemu-guest-agent sudo reboot

List
virsh --connect qemu:///system list --all

Start
virsh --connect qemu:///system start ''

Stop
virsh --connect qemu:///system stop ''

Reboot
virsh --connect qemu:///system stop ''

Information
Offical Web Site

Ubuntu Official Documentation