By: Rafael Folco
OpenStack uses virtio driver as default model for both networking and disk devices. Virtio takes advantage of paravirtualization and enables guests to get high performance network and disk operations. However, OpenStack also supports some alternate options to enable custom models for KVM/Qemu hypervisor.
In order to use custom models, KVM users can change the image_meta properties and select the desired driver.
IBM PowerKVM provides support to ibmveth and ibmvscsi drivers as an alternative to the default virtio driver. These legacy drivers came from the PowerVM Hypervisor and are now supported by PowerKVM.
At the time of writing, for ibmvscsi, there is no change needed in OpenStack code. On the other hand, for ibmveth, a patch is required. The upstream change that reflects this driver support has been addressed in https://review.openstack.org/#/c/106451/.
The image_meta properties to change are hw_vif_model for ibmveth and hw_disk_bus for ibmvscsi. This is shown in the following example:
$ glance image-create --name "my_image" --is-public true --disk-format qcow2 --container-format bare --property hw_vif_model='spapr-vlan' --property hw_disk_bus='scsi' --file my_image.img
For more information about IBM PowerKVM refer to the Redbook.