diff --git a/doc/config-ref-rst/source/compute/hypervisor-qemu.rst b/doc/config-ref-rst/source/compute/hypervisor-qemu.rst index e0690edb4e..78cecac30c 100644 --- a/doc/config-ref-rst/source/compute/hypervisor-qemu.rst +++ b/doc/config-ref-rst/source/compute/hypervisor-qemu.rst @@ -1,3 +1,54 @@ ==== QEMU ==== + +From the perspective of the Compute service, the QEMU hypervisor is +very similar to the KVM hypervisor. Both are controlled through libvirt, +both support the same feature set, and all virtual machine images that +are compatible with KVM are also compatible with QEMU. +The main difference is that QEMU does not support native virtualization. +Consequently, QEMU has worse performance than KVM and is a poor choice +for a production deployment. + +The typical uses cases for QEMU are + +* Running on older hardware that lacks virtualization support. +* Running the Compute service inside of a virtual machine for + development or testing purposes, where the hypervisor does not + support native virtualization for guests. + +To enable QEMU, add these settings to ``nova.conf``: + +.. code-block:: ini + + compute_driver = libvirt.LibvirtDriver + + [libvirt] + virt_type = qemu + +For some operations you may also have to install the +:command:`guestmount` utility: + +On Ubuntu: + +.. code-block:: console + + # apt-get install guestmount + +On Red Hat Enterprise Linux, Fedora, or CentOS: + +.. code-block:: console + + # yum install libguestfs-tools + +On openSUSE: + +.. code-block:: console + + # zypper install guestfs-tools + +The QEMU hypervisor supports the following virtual machine image formats: + +* Raw +* QEMU Copy-on-write (qcow2) +* VMware virtual machine disk format (vmdk)