OpenStack Compute supports many hypervisors, which might make it difficult for you to choose one. Most installations use only one hypervisor. However, you can use and to schedule different hypervisors within the same installation. The following links help you choose a hypervisor. See http://docs.openstack.org/developer/nova/support-matrix.html for a detailed list of features and support across the hypervisors. The following hypervisors are supported: KVM - Kernel-based Virtual Machine. The virtual disk formats that it supports is inherited from QEMU since it uses a modified QEMU program to launch the virtual machine. The supported formats include raw images, the qcow2, and VMware formats. LXC - Linux Containers (through libvirt), used to run Linux-based virtual machines. QEMU - Quick EMUlator, generally only used for development purposes. UML - User Mode Linux, generally only used for development purposes. VMware vSphere 4.1 update 1 and newer, runs VMware-based Linux and Windows images through a connection with a vCenter server or directly with an ESXi host. Xen (using libvirt) - Xen Project Hypervisor using libvirt as management interface into nova-compute to run Linux, Windows, FreeBSD and NetBSD virtual machines. XenServer - XenServer, Xen Cloud Platform (XCP) and other XAPI based Xen variants runs Linux or Windows virtual machines. You must install the nova-compute service in a para-virtualized VM. Hyper-V - Server virtualization with Microsoft's Hyper-V, use to run Windows, Linux, and FreeBSD virtual machines. Runs nova-compute natively on the Windows virtualization platform.

The node where the nova-compute service is installed and operates on the same node that runs all of the virtual machines. This is referred to as the compute node in this guide. By default, the selected hypervisor is KVM. To change to another hypervisor, change the virt_type option in the [libvirt] section of nova.conf and restart the nova-compute service. Here are the general nova.conf options that are used to configure the compute node's hypervisor: . Specific options for particular hypervisors can be found in the following sections.