--- features: - Add support for enabling discard support for block devices with libvirt. This will be enabled for Cinder volume attachments that specify support for the feature in their connection properties. This requires support to be present in the version of libvirt (v1.0.6+) and qemu (v1.6.0+) used along with the configured virtual drivers for the instance. The virtio-blk driver does not support this functionality.