Comment 3 for bug 1317880

When an instance boots from a image, its 'image' param seems be equal to '', like boots from a volume/snapshot.

IMO if you don't createVM using original '--image-id' method, Nova will always treat it as a volume-backend instance. So the 'image' will always be '' in the situation.

Is the issue caused by the horizon or other portals use '' to query the image from Glance?

I checked the codes in novaclient, the process is like this:
# if image:
# ...
# else: # Booted from volume
# info['image'] = _("Attempt to boot from volume - no image supplied")