Comment 5 for bug 1416321

http://logs.openstack.org/06/150206/6/check-tripleo/check-tripleo-ironic-overcloud-f20-nonha/3b1268c/logs/ov-i6a3r2vbqm-1-qrud6cls6p6r-NovaCompute_logs/nova-compute.txt.gz#_Jan_30_09_29_00

Jan 30 09:29:00 ov-i6a3r2vbqm-1-qrud6cls6p6r-novacompute-mpl6wabwvv2p nova-compute[4285]: 2015-01-30 09:29:00,119 ERROR Failure prepping block device
                                                                                          Traceback (most recent call last):
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/compute/manager.py", line 2274, in _build_resources
                                                                                              block_device_mapping)
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/compute/manager.py", line 1811, in _default_block_device_names
                                                                                              root_bdm)
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/compute/manager.py", line 1770, in _default_root_device_name
                                                                                              root_bdm)
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 6186, in default_root_device_name
                                                                                              cdrom_bus)
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/virt/libvirt/blockinfo.py", line 432, in get_root_info
                                                                                              root_bdm, disk_bus)
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/virt/libvirt/blockinfo.py", line 375, in get_info_from_bdm
                                                                                              device_name = find_disk_dev_for_disk_bus(padded_mapping, bdm_bus)
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/virt/libvirt/blockinfo.py", line 189, in find_disk_dev_for_disk_bus
                                                                                              if not has_disk_dev(mapping, disk_dev):
                                                                                            File "/opt/stack/venvs/nova/lib/python2.7/site-packages/nova/virt/libvirt/blockinfo.py", line 105, in has_disk_dev
                                                                                              info = mapping[disk]
                                                                                          TypeError: string indices must be integers, not str