Instances are failing to fully spawn on compute node

Issue

• We have recently noticed that one of our compute nodes is usually unable to complete the creation of an instance. The logs suggest that the error occurs at the libvirt level, and that when the error occurs the instance is moved to another node, where it spawns successfully.

• For example, in nova-compute.log, instance 3e007e84-5934-466a-a95f-882737d0382c was claimed for overcloud-compute-9 (the problematic node) with request id 71f66177-d84e-4d97-ae6b-687518e12585. The claim was successful, but then the error 'Error launching a defined domain with XML: ' is observed, along with 'Failed to start libvirt guest: libvirt.libvirtError: internal error: Child process (tc filter add dev tapfd5fa6bb-4f parent ffff: protocol all u32 match u32 0 0 police rate 131072kbps burst 131072kb mtu 64kb drop flowid :1) unexpected exit status 2: Error: Parent Qdisc doesn't exists.' Then in our controller logs we see python tracebacks with similar errors.

• We have nine other compute nodes and we have not observed this behaviour on them. We run smoke tests every two minutes, and whenever overcloud-compute-0 is selected for an instance this error will usually occur. We have also run manual instance creations and observed the same behaviour.

• Flavor looks like:

(overcloud) [stack@undercloud ~]$ openstack flavor show m1.vsmall --fit
+----------------------------+------------------------------------------------------------------------------------------------------------------+
| Field                      | Value                                                                                                            |
+----------------------------+------------------------------------------------------------------------------------------------------------------+
| OS-FLV-DISABLED:disabled   | False                                                                                                            |
| OS-FLV-EXT-DATA:ephemeral  | 0                                                                                                                |
| access_project_ids         | None                                                                                                             |
| description                | None                                                                                                             |
| disk                       | 10                                                                                                               |
| extra_specs                | {'quota:disk_total_bytes_sec': '52428800', 'quota:disk_total_iops_sec': '600', 'quota:vif_inbound_average':      |
|                            | '131072', 'quota:vif_inbound_burst': '131072', 'quota:vif_inbound_peak': '131072', 'quota:vif_outbound_average': |
|                            | '131072', 'quota:vif_outbound_burst': '131072', 'quota:vif_outbound_peak': '131072'}                             |
| id                         | a0bc3a98-9aca-47d2-ae30-016adc167b50                                                                             |
| name                       | m1.vsmall                                                                                                        |
| os-flavor-access:is_public | True                                                                                                             |
| properties                 | quota:disk_total_bytes_sec='52428800', quota:disk_total_iops_sec='600', quota:vif_inbound_average='131072',      |
|                            | quota:vif_inbound_burst='131072', quota:vif_inbound_peak='131072', quota:vif_outbound_average='131072',          |
|                            | quota:vif_outbound_burst='131072', quota:vif_outbound_peak='131072'                                              |
| ram                        | 1024                                                                                                             |
| rxtx_factor                | 1.0                                                                                                              |
| swap                       | 0                                                                                                                |
| vcpus                      | 1                                                                                                                |
+----------------------------+------------------------------------------------------------------------------------------------------------------+