This is interesting I have two host compute-06 & compute-07 06 --> 07 (very slow migration) 07 --> 06 ( super fast migration) [root@ostack-compute-07 ~]# nova --version 10.1.0 Here is the logs of (06-to-07 migration) you can see its very slow even after your patch 2018-08-23 18:11:38.026 37085 WARNING nova.compute.manager [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Received unexpected event network-vif-plugged-1399100a-77c1-43eb-8d95-fc73a91b6bed for instance with vm_state active and task_state migrating. 2018-08-23 18:11:57.759 37085 INFO nova.virt.libvirt.driver [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Migration running for 30 secs, memory 44% remaining; (bytes processed=33072816, remaining=484225024, total=1091379200) 2018-08-23 18:11:57.821 37085 WARNING nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Instance not resizing, skipping migration. 2018-08-23 18:11:57.853 37085 INFO nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] Final resource view: name=ostack-compute-07.foo.net phys_ram=32733MB used_ram=5120MB phys_disk=9314GB used_disk=20GB total_vcpus=40 used_vcpus=2 pci_stats=[] 2018-08-23 18:12:28.721 37085 INFO nova.virt.libvirt.driver [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Migration running for 60 secs, memory 41% remaining; (bytes processed=66046896, remaining=451284992, total=1091379200) 2018-08-23 18:12:37.212 37085 INFO nova.compute.manager [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] During sync_power_state the instance has a pending task (migrating). Skip. 2018-08-23 18:12:58.700 37085 WARNING nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Instance not resizing, skipping migration. 2018-08-23 18:12:58.734 37085 INFO nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] Final resource view: name=ostack-compute-07.foo.net phys_ram=32733MB used_ram=5120MB phys_disk=9314GB used_disk=20GB total_vcpus=40 used_vcpus=2 pci_stats=[] 2018-08-23 18:12:59.712 37085 INFO nova.virt.libvirt.driver [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Migration running for 90 secs, memory 38% remaining; (bytes processed=99128228, remaining=417992704, total=1091379200) 2018-08-23 18:13:30.680 37085 INFO nova.virt.libvirt.driver [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Migration running for 120 secs, memory 35% remaining; (bytes processed=132209002, remaining=384954368, total=1091379200) 2018-08-23 18:13:56.995 37085 INFO nova.virt.libvirt.migration [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Increasing downtime to 95 ms after 150 sec elapsed time 2018-08-23 18:13:58.565 37085 WARNING nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Instance not resizing, skipping migration. 2018-08-23 18:13:58.596 37085 INFO nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] Final resource view: name=ostack-compute-07.foo.net phys_ram=32733MB used_ram=5120MB phys_disk=9314GB used_disk=20GB total_vcpus=40 used_vcpus=2 pci_stats=[] 2018-08-23 18:14:01.711 37085 INFO nova.virt.libvirt.driver [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Migration running for 150 secs, memory 32% remaining; (bytes processed=165290010, remaining=351809536, total=1091379200) 2018-08-23 18:14:32.700 37085 INFO nova.virt.libvirt.driver [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Migration running for 180 secs, memory 29% remaining; (bytes processed=198370955, remaining=318693376, total=1091379200) 2018-08-23 18:14:58.762 37085 WARNING nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Instance not resizing, skipping migration. 2018-08-23 18:14:58.802 37085 INFO nova.compute.resource_tracker [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] Final resource view: name=ostack-compute-07.foo.net phys_ram=32733MB used_ram=5120MB phys_disk=9314GB used_disk=20GB total_vcpus=40 used_vcpus=2 pci_stats=[] 2018-08-23 18:15:03.626 37085 INFO nova.virt.libvirt.driver [req-a9fe2b70-af22-4d6e-bee0-ddc64be0cf09 c3c091aa18b340fdaad9f95afeb4493c 328fc75d4f944a64ad1b8699c02350ca - default default] [instance: 6ce9af65-4e5d-45a2-91a5-0d42f5622022] Migration running for 210 secs, memory 25% remaining; (bytes processed=231349769, remaining=276144128, total=1091379200)