KVM is configured as the default hypervisor for Compute. To enable KVM explicitly, add the
following configuration options
/etc/nova/nova.conf:
connection_type=libvirt libvirt_type=kvm
The KVM hypervisor supports the following virtual machine image formats:
Raw
QEMU Copy-on-write (qcow2)
VMWare virtual machine disk format (vmdk)
The rest of this section describes how to enable KVM on your system. You may also wish to consult distribution-specific documentation:
Fedora: Getting started with virtualization from the Fedora project wiki.
Ubuntu: KVM/Installation from the Community Ubuntu documentation.
Debian: Virtualization with KVM from the Debian handbook.
RHEL: Installing virtualization packages on an existing Red Hat Enterprise Linux system from the Red Hat Enterprise Linux Virtualizaiton Host Configuration and Guest Installation Guide.
openSUSE: Installing KVM from the openSUSE Virtualization with KVM manual.
SLES: Installing KVM from the SUSE Linux Enterprise ServerVirtualization with KVM manual.
The processors of your compute host need to support virtualization technology (VT) to use KVM.
If you are running on Ubuntu, use the kvm-ok command to check if your processor has VT support, it is enabled in the BIOS, and KVM is installed properly, as root:
# kvm-ok
If KVM is enabled, the output should look something like:
INFO: /dev/kvm exists KVM acceleration can be used
If KVM is not enabled, the output should look something like:
INFO: Your CPU does not support KVM extensions KVM acceleration can NOT be used
In the case that KVM acceleration is not supported, Compute should be configured to use a different hypervisor, such as QEMU or Xen.
On distributions that don't have kvm-ok, you can check if your
processor has VT support by looking at the processor flags in the
/proc/cpuinfo file. For Intel processors, look for the
vmx flag, and for AMD processors, look for the
svm flag. A simple way to check is to run the following command
and see if there is any
output:
$ egrep '(vmx|svm)' --color=always /proc/cpuinfo
Some systems require that you enable VT support in the system BIOS. If you believe your processor supports hardware acceleration but the above command produced no output, you may need to reboot your machine, enter the system BIOS, and enable the VT option.
KVM requires the kvm and either kvm-intel or
kvm-amd modules to be loaded. This may have been configured
automatically on your distribution when KVM is installed.
You can check that they have been loaded using lsmod, as follows, with expected output for Intel-based processors:
$ lsmod | grep kvm kvm_intel 137721 9 kvm 415459 1 kvm_intel
The following sections describe how to load the kernel modules for Intel-based and AMD-based processors if they were not loaded automatically by your distribution's KVM installation process.
If your compute host is Intel-based, run the following as root to load the kernel modules:
# modprobe kvm # modprobe kvm-intel
Add the following lines to /etc/modules so that these modules
will load on reboot:
kvm kvm-intel
