Instances have been observed to remain stuck forever in "BUILD" state, with no errors surfaced to `nova show` after nova boot fails with the following guestfs error.
2013-03-20 18:49:08,590.590 ERROR nova.compute.manager [req-f85ccdcd-74f1-4f50-98eb-b68fb8dc8e1a dba071d520c9438ab9fb91077b6f3248 1ba6328ea66c4041bfab7cfcbc2305cf] [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] Instance failed to spawn
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] Traceback (most recent call last):
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] File "/usr/local/lib/python2.7/dist-packages/nova/compute/manager.py", line 1055, in _spawn
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] block_device_info)
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] File "/usr/local/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 1517, in spawn
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] admin_pass=admin_password)
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] File "/usr/local/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 1913, in _create_image
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] instance=instance)
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] File "/usr/lib/python2.7/contextlib.py", line 24, in __exit__
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] self.gen.next()
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] File "/usr/local/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 1908, in _create_image
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] mandatory=('files',))
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] File "/usr/local/lib/python2.7/dist-packages/nova/virt/disk/api.py", line 304, in inject_data
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] fs.setup()
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] File "/usr/local/lib/python2.7/dist-packages/nova/virt/disk/vfs/guestfs.py", line 114, in setup
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] {'imgfile': self.imgfile, 'e': e})
2013-03-20 18:49:08,590.590 14139 TRACE nova.compute.manager [instance: 5f3fe8ba-a148-48e5-8e19-d2f65968b2db] NovaException: Error mounting /var/lib/nova/instances/5f3fe8ba-a148-48e5-8e19-d2f65968b2db/disk with libguestfs (cannot find any suitable libguestfs supermin, fixed or old-style appliance on LIBGUESTFS_PATH (search path: /usr/lib/guestfs))
What version of nova?