LibvirtDriver's _get_instance_disk_info calls libvirt_utils.get_disk_backing_file() if processing a qcow2 backing file. If this is a file belonging to an attached and NFS-hosted Cinder volume, it may be owned by qemu:qemu and therefore not readable as the nova user.
My proposed solution is to run the images.qemu_img_info() call as root in this case.
Note that this requires a change to grenade to upgrade the rootwrap configuration for gating to pass.
LibvirtDriver's _get_instance_ disk_info calls libvirt_ utils.get_ disk_backing_ file() if processing a qcow2 backing file. If this is a file belonging to an attached and NFS-hosted Cinder volume, it may be owned by qemu:qemu and therefore not readable as the nova user.
My proposed solution is to run the images. qemu_img_ info() call as root in this case.
Note that this requires a change to grenade to upgrade the rootwrap configuration for gating to pass.