@Matt, Hi, I was testing on Master back in Nov. 2016 so it must be Ocata. And I tested again with the current master in my devstack env: I raise exception.InterfaceAttachFailed(instance_uuid=instance.uuid) directly at: http://git.openstack.org/cgit/openstack/nova/tree/nova/virt/libvirt/driver.py#n1392 to create the attach failure scenario. and then I create a port: root@SZX1000291919:/opt/stack/nova# neutron port-create 72cc44fa-575b-4eee-8b31-62628a6849a6 neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead. Created a new port: +-----------------------+------------------------------------------------------------------------------------+ | Field | Value | +-----------------------+------------------------------------------------------------------------------------+ | admin_state_up | True | | allowed_address_pairs | | | binding:host_id | | | binding:profile | {} | | binding:vif_details | {} | | binding:vif_type | unbound | | binding:vnic_type | normal | | created_at | 2017-04-19T02:06:20Z | | description | | | device_id | | | device_owner | | | extra_dhcp_opts | | | fixed_ips | {"subnet_id": "146fd32e-e896-4b98-8edb-60583d3fa886", "ip_address": "172.24.4.9"} | | | {"subnet_id": "8b9f5ac6-0dfa-4c7b-bcb1-e3f10874570c", "ip_address": "2001:db8::9"} | | id | f87cac88-0303-4e0e-9831-9e843db892ef | | mac_address | fa:16:3e:6e:b2:03 | | name | | | network_id | 72cc44fa-575b-4eee-8b31-62628a6849a6 | | port_security_enabled | True | | project_id | 3e1e1a22750840d591509807b0251acb | | revision_number | 6 | | security_groups | c0f36b5e-dc65-4209-9529-5a72e2ed8f1b | | status | DOWN | | tags | | | tenant_id | 3e1e1a22750840d591509807b0251acb | | updated_at | 2017-04-19T02:06:20Z | +-----------------------+------------------------------------------------------------------------------------+ root@SZX1000291919:/opt/stack/nova# neutron port-list neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead. +--------------------------------------+------+----------------------------------+-------------------+-------------------------------------------------------------------------------------------------------------+ | id | name | tenant_id | mac_address | fixed_ips | +--------------------------------------+------+----------------------------------+-------------------+-------------------------------------------------------------------------------------------------------------+ | 295440a7-a4e7-47b5-bfb5-20d38c0a6786 | | | fa:16:3e:5b:b4:7e | {"subnet_id": "146fd32e-e896-4b98-8edb-60583d3fa886", "ip_address": "172.24.4.6"} | | | | | | {"subnet_id": "8b9f5ac6-0dfa-4c7b-bcb1-e3f10874570c", "ip_address": "2001:db8::1"} | | 6cedc98f-1179-4a68-854a-ef8baa9d4199 | | 3e1e1a22750840d591509807b0251acb | fa:16:3e:e2:ab:5a | {"subnet_id": "d30c955b-2719-49d3-9c4b-991847cb332b", "ip_address": "10.0.0.12"} | | | | | | {"subnet_id": "010b64b9-8f3f-4087-a7a5-fd446ca0254f", "ip_address": "fd60:cdc5:3b4f:0:f816:3eff:fee2:ab5a"} | | 9e44e2b2-db9e-4c90-9ff0-c18aaa753f9a | | e4ab939775f943f685ff02042490fe6d | fa:16:3e:da:52:cc | {"subnet_id": "d30c955b-2719-49d3-9c4b-991847cb332b", "ip_address": "10.0.0.2"} | | | | | | {"subnet_id": "010b64b9-8f3f-4087-a7a5-fd446ca0254f", "ip_address": "fd60:cdc5:3b4f:0:f816:3eff:feda:52cc"} | | 9fb2b024-62c5-4c43-8140-3a08cbc4694c | | e4ab939775f943f685ff02042490fe6d | fa:16:3e:17:67:60 | {"subnet_id": "d30c955b-2719-49d3-9c4b-991847cb332b", "ip_address": "10.0.0.1"} | | f2b66a85-e02b-4fb3-b603-5c1f9bd59d72 | | e4ab939775f943f685ff02042490fe6d | fa:16:3e:ca:b4:19 | {"subnet_id": "010b64b9-8f3f-4087-a7a5-fd446ca0254f", "ip_address": "fd60:cdc5:3b4f::1"} | | f87cac88-0303-4e0e-9831-9e843db892ef | | 3e1e1a22750840d591509807b0251acb | fa:16:3e:6e:b2:03 | {"subnet_id": "146fd32e-e896-4b98-8edb-60583d3fa886", "ip_address": "172.24.4.9"} | | | | | | {"subnet_id": "8b9f5ac6-0dfa-4c7b-bcb1-e3f10874570c", "ip_address": "2001:db8::9"} | +--------------------------------------+------+----------------------------------+-------------------+-------------------------------------------------------------------------------------------------------------+ The port id of the newly created port is f87cac88-0303-4e0e-9831-9e843db892ef ========================================================================================================= Then attach it to the instance: root@SZX1000291919:/opt/stack/nova# nova interface-attach e3d024eb-b2aa-44b2-a5b6-610d1ff7d188 --port-id f87cac88-0303-4e0e-9831-9e843db892ef /usr/local/lib/python2.7/dist-packages/novaclient/client.py:278: UserWarning: The 'tenant_id' argument is deprecated in Ocata and its use may result in errors in future releases. As 'project_id' is provided, the 'tenant_id' argument will be ignored. warnings.warn(msg) ERROR (ClientException): Failed to attach network adapter device to e3d024eb-b2aa-44b2-a5b6-610d1ff7d188 (HTTP 500) (Request-ID: req-03308477-7bda-4375-b724-a0c1e8b77ee9) Error raised as I raised it directly =================================================================================================================== List again all ports, f87cac88-0303-4e0e-9831-9e843db892ef is missing root@SZX1000291919:/opt/stack/nova# neutron port-list neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead. +--------------------------------------+------+----------------------------------+-------------------+-------------------------------------------------------------------------------------------------------------+ | id | name | tenant_id | mac_address | fixed_ips | +--------------------------------------+------+----------------------------------+-------------------+-------------------------------------------------------------------------------------------------------------+ | 295440a7-a4e7-47b5-bfb5-20d38c0a6786 | | | fa:16:3e:5b:b4:7e | {"subnet_id": "146fd32e-e896-4b98-8edb-60583d3fa886", "ip_address": "172.24.4.6"} | | | | | | {"subnet_id": "8b9f5ac6-0dfa-4c7b-bcb1-e3f10874570c", "ip_address": "2001:db8::1"} | | 6cedc98f-1179-4a68-854a-ef8baa9d4199 | | 3e1e1a22750840d591509807b0251acb | fa:16:3e:e2:ab:5a | {"subnet_id": "d30c955b-2719-49d3-9c4b-991847cb332b", "ip_address": "10.0.0.12"} | | | | | | {"subnet_id": "010b64b9-8f3f-4087-a7a5-fd446ca0254f", "ip_address": "fd60:cdc5:3b4f:0:f816:3eff:fee2:ab5a"} | | 9e44e2b2-db9e-4c90-9ff0-c18aaa753f9a | | e4ab939775f943f685ff02042490fe6d | fa:16:3e:da:52:cc | {"subnet_id": "d30c955b-2719-49d3-9c4b-991847cb332b", "ip_address": "10.0.0.2"} | | | | | | {"subnet_id": "010b64b9-8f3f-4087-a7a5-fd446ca0254f", "ip_address": "fd60:cdc5:3b4f:0:f816:3eff:feda:52cc"} | | 9fb2b024-62c5-4c43-8140-3a08cbc4694c | | e4ab939775f943f685ff02042490fe6d | fa:16:3e:17:67:60 | {"subnet_id": "d30c955b-2719-49d3-9c4b-991847cb332b", "ip_address": "10.0.0.1"} | | f2b66a85-e02b-4fb3-b603-5c1f9bd59d72 | | e4ab939775f943f685ff02042490fe6d | fa:16:3e:ca:b4:19 | {"subnet_id": "010b64b9-8f3f-4087-a7a5-fd446ca0254f", "ip_address": "fd60:cdc5:3b4f::1"} | +--------------------------------------+------+----------------------------------+-------------------+-------------------------------------------------------------------------------------------------------------+ So seems the bug is still valid in current master, but correct me if I did something wrong.