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[Bug 1969592] [NEW] [OVN] Frequent DB leader changes causes 'VIF creation failed' on nova side

To: yahoo-eng-team@xxxxxxxxxxxxxxxxxxx
From: Oleg Konobeev <1969592@xxxxxxxxxxxxxxxxxx>
Date: Wed, 20 Apr 2022 08:59:29 -0000
Reply-to: Bug 1969592 <1969592@xxxxxxxxxxxxxxxxxx>
Sender: noreply@xxxxxxxxxxxxx
Public bug reported:

Hello guys.

As I found in 2021 there was a commit to OVS [since OVS v2.16 or 2.15 with that backport] that changed behavior during OVN DBs snapshoting. 
Now before the leader creates a snapshot it will transfer leadership to another node. 

We've run tests with rally and tempest and looks like there is a problem now when there is interaction between nova and neutron. 
For example, simple rally test like 'create {network,router,subnet} -> add interface to router' looks okay even with 256 concurrent same tests/threads. But something like 'neutron.create_subnet -> nova.boot_server -> nova.attach_interface' will fail in time when transfer leadership happens. 
Since it happens to often [ each 10m + rand(10) ] we will get a lot of errors. 

This problem can be observed on all versions where OVS 2.16 [or
backport] or higher invited :)


Some tracing from logs [neutron, nova, ovn-sb-db]:

CONTROL-NODES:


ctl01-ovn-sb-db.log:2022-04-19T12:30:03.089Z|01002|raft|INFO|Transferring leadership to write a snapshot.
ctl01-ovn-sb-db.log:2022-04-19T12:30:03.099Z|01003|raft|INFO|server 1c5f is leader for term 42

ctl03-ovn-sb-db.log:2022-04-19T12:30:03.090Z|00938|raft|INFO|received leadership transfer from 1f46 in term 41
ctl03-ovn-sb-db.log:2022-04-19T12:30:03.092Z|00940|raft|INFO|term 42: elected leader by 2+ of 3 servers
ctl03-ovn-sb-db.log:2022-04-19T12:30:10.941Z|00941|jsonrpc|WARN|tcp:xx.yy.zz.26:41882: send error: Connection reset by peer
ctl03-ovn-sb-db.log:2022-04-19T12:30:27.324Z|00943|jsonrpc|WARN|tcp:xx.yy.zz.26:41896: send error: Connection reset by peer
ctl03-ovn-sb-db.log:2022-04-19T12:30:27.325Z|00945|jsonrpc|WARN|tcp:xx.yy.zz.26:41880: send error: Connection reset by peer
ctl03-ovn-sb-db.log:2022-04-19T12:30:27.325Z|00947|jsonrpc|WARN|tcp:xx.yy.zz.26:41892: send error: Connection reset by peer
ctl03-ovn-sb-db.log:2022-04-19T12:30:27.327Z|00949|jsonrpc|WARN|tcp:xx.yy.zz.26:41884: send error: Connection reset by peer
ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00951|jsonrpc|WARN|tcp:xx.yy.zz.25:40260: send error: Connection timed out
ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00953|jsonrpc|WARN|tcp:xx.yy.zz.25:40264: send error: Connection timed out
ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00955|jsonrpc|WARN|tcp:xx.yy.zz.24:37440: send error: Connection timed out
ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00957|jsonrpc|WARN|tcp:xx.yy.zz.24:37442: send error: Connection timed out
ctl03-ovn-sb-db.log:2022-04-19T12:31:49.245Z|00959|jsonrpc|WARN|tcp:xx.yy.zz.24:37446: send error: Connection timed out
ctl03-ovn-sb-db.log:2022-04-19T12:32:01.533Z|01001|jsonrpc|WARN|tcp:xx.yy.zz.67:57586: send error: Connection timed out


2022-04-19 12:30:08.898 27 INFO neutron.db.ovn_revision_numbers_db [req-7fcfdd74-482d-46b2-9f76-07190669d76d ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 - default default] Successfully bumped revision number for resource be178a9a-26d7-4bf0-a4e8-d206a6965205 (type: ports) to 1

2022-04-19 12:30:09.644 27 INFO neutron.db.ovn_revision_numbers_db
[req-a8278418-3ad9-450c-89bb-e7a5c1c0a06d
a9864cd890224c079051b3f56021be64 72db34087b9b401d842b66643b647e16 -
default default] Successfully bumped revision number for resource
be178a9a-26d7-4bf0-a4e8-d206a6965205 (type: ports) to 2


2022-04-19 12:30:10.235 27 INFO neutron.wsgi [req-571b53cc-ca04-46f7-89f9-fdf8e5931f4c a9864cd890224c079051b3f56021be64 72db34087b9b401d842b66643b647e16 - default default] xx.yy.zz.68,xx.yy.zz.26 "GET /v2.0/ports?tenant_id=9d3ae9a7b121488285203b0fdeabc3a3&device_id=7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 HTTP/1.1" status: 200  len: 1081 time: 0.0363808

2022-04-19 12:30:10.395 25 INFO
nova.api.openstack.compute.server_external_events
[req-d144458a-ca21-4e92-b5be-4f589e118d8c
4688fc44551b45c6a761c9c0351e76a8 72db34087b9b401d842b66643b647e16 -
default default] Creating event network-
changed:be178a9a-26d7-4bf0-a4e8-d206a6965205 for instance
7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 on cmp-ucs-01-05.poc.example.com


2022-04-19 12:30:10.402 27 INFO neutron.notifiers.nova [-] Nova event response: {'name': 'network-changed', 'server_uuid': '7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34', 'tag': 'be178a9a-26d7-4bf0-a4e8-d206a6965205', 'status': 'completed', 'code': 200}

2022-04-19 12:33:01.497 34 INFO neutron.db.ovn_revision_numbers_db
[req-82f3d4fe-1276-4918-86d3-55cc42ca2816 - - - - -] Successfully bumped
revision number for resource be178a9a-26d7-4bf0-a4e8-d206a6965205 (type:
ports) to 3

COMPUTE-NODES:

ovs-vswitchd.log:2022-04-19T12:30:10.743Z|08415|bridge|INFO|bridge br-int: added interface tapbe178a9a-26 on port 874
ovn-controller.log:2022-04-19T12:30:11.251Z|02356|binding|INFO|Claiming lport be178a9a-26d7-4bf0-a4e8-d206a6965205 for this chassis.
ovn-controller.log:2022-04-19T12:30:11.251Z|02357|binding|INFO|be178a9a-26d7-4bf0-a4e8-d206a6965205: Claiming fa:16:3e:8f:3b:47 1.80.1.254

nova-compute.log:2022-04-19 12:30:10.672 8 INFO os_vif
[req-2c8b5f82-ce4a-4aa7-9f0a-d346ee210ffb
ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 -
default default] Successfully plugged vif
VIFOpenVSwitch(active=False,address=fa:16:3e:8f:3b:47,bridge_name='br-
int',has_traffic_filtering=True,id=be178a9a-26d7-4bf0-a4e8-d206a6965205,network=Network(5dd2512b-56f8-4e04-8623-971a633a76aa),plugin='ovs',port_profile=VIFPortProfileOpenVSwitch,preserve_on_delete=False,vif_name='tapbe178a9a-26')

ovs-vswitchd.log:2022-04-19T12:35:11.302Z|08448|bridge|INFO|bridge br-int: deleted interface tapbe178a9a-26 on port 874
ovn-controller.log:2022-04-19T12:35:11.307Z|02380|binding|INFO|Releasing lport be178a9a-26d7-4bf0-a4e8-d206a6965205 from this chassis.

2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [req-2c8b5f82-ce4a-4aa7-9f0a-d346ee210ffb ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 - default default] [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Failed to
 allocate network(s): nova.exception.VirtualInterfaceCreateException: Virtual Interface creation failed
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Traceback (most recent call last):
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 7260, in _create_guest_with_network
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     post_xml_callback=post_xml_callback)
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/usr/lib64/python3.6/contextlib.py", line 88, in __exit__
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     next(self.gen)
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/compute/manager.py", line 479, in wait_for_instance_event
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     actual_event = event.wait()
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/event.py", line 125, in wait
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     result = hub.switch()
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/hubs/hub.py", line 313, in switch
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     return self.greenlet.switch()
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] eventlet.timeout.Timeout: 300 seconds
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] 
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] During handling of the above exception, another exception occurred:
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] 
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Traceback (most recent call last):
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/compute/manager.py", line 2402, in _build_and_run_instance
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     accel_info=accel_info)
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 4225, in spawn
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     cleanup_instance_disks=created_disks)
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 7283, in _create_guest_with_network
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     raise exception.VirtualInterfaceCreateException()
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] nova.exception.VirtualInterfaceCreateException: Virtual Interface creation failed
2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] 
2022-04-19 12:35:11.844 8 ERROR nova.compute.manager [req-2c8b5f82-ce4a-4aa7-9f0a-d346ee210ffb ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 - default default] [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Build of 
instance 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 aborted: Failed to allocate the network(s), not rescheduling.: nova.exception.BuildAbortException: Build of instance 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 aborted: Failed to allocate the networ
k(s), not rescheduling.


CONTROL:

2022-04-19 12:35:11.330 25 INFO
neutron.plugins.ml2.drivers.ovn.mech_driver.mech_driver
[req-2b4d10b1-3a7a-4683-97df-990259705b46 - - - - -] OVN reports status
down for port: be178a9a-26d7-4bf0-a4e8-d206a6965205

2022-04-19 12:35:12.524 23 WARNING neutron.notifiers.nova [-] Nova
event: {'server_uuid': '7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34', 'name':
'network-vif-deleted', 'tag': 'be178a9a-26d7-4bf0-a4e8-d206a6965205',
'status': 'failed', 'code': 422} returned with failed status

/var/log/kolla/neutron/neutron-server.log:2022-04-19 12:35:13.016 25
WARNING neutron.notifiers.nova [-] Nova event: {'server_uuid':
'7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34', 'name': 'network-vif-plugged',
'status': 'failed', 'tag': 'be178a9a-26d7-4bf0-a4e8-d206a6965205',
'code': 422} returned with failed status

** Affects: neutron
     Importance: Undecided
         Status: New

** Affects: nova
     Importance: Undecided
         Status: New


** Tags: neutron ovn

** Also affects: nova
   Importance: Undecided
       Status: New

** Tags added: neutron ovn

-- 
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https://bugs.launchpad.net/bugs/1969592

Title:
  [OVN] Frequent DB leader changes causes 'VIF creation failed' on nova
  side

Status in neutron:
  New
Status in OpenStack Compute (nova):
  New

Bug description:
  Hello guys.

  As I found in 2021 there was a commit to OVS [since OVS v2.16 or 2.15 with that backport] that changed behavior during OVN DBs snapshoting. 
  Now before the leader creates a snapshot it will transfer leadership to another node. 

  We've run tests with rally and tempest and looks like there is a problem now when there is interaction between nova and neutron. 
  For example, simple rally test like 'create {network,router,subnet} -> add interface to router' looks okay even with 256 concurrent same tests/threads. But something like 'neutron.create_subnet -> nova.boot_server -> nova.attach_interface' will fail in time when transfer leadership happens. 
  Since it happens to often [ each 10m + rand(10) ] we will get a lot of errors. 

  This problem can be observed on all versions where OVS 2.16 [or
  backport] or higher invited :)

  
  Some tracing from logs [neutron, nova, ovn-sb-db]:

  CONTROL-NODES:

  
  ctl01-ovn-sb-db.log:2022-04-19T12:30:03.089Z|01002|raft|INFO|Transferring leadership to write a snapshot.
  ctl01-ovn-sb-db.log:2022-04-19T12:30:03.099Z|01003|raft|INFO|server 1c5f is leader for term 42

  ctl03-ovn-sb-db.log:2022-04-19T12:30:03.090Z|00938|raft|INFO|received leadership transfer from 1f46 in term 41
  ctl03-ovn-sb-db.log:2022-04-19T12:30:03.092Z|00940|raft|INFO|term 42: elected leader by 2+ of 3 servers
  ctl03-ovn-sb-db.log:2022-04-19T12:30:10.941Z|00941|jsonrpc|WARN|tcp:xx.yy.zz.26:41882: send error: Connection reset by peer
  ctl03-ovn-sb-db.log:2022-04-19T12:30:27.324Z|00943|jsonrpc|WARN|tcp:xx.yy.zz.26:41896: send error: Connection reset by peer
  ctl03-ovn-sb-db.log:2022-04-19T12:30:27.325Z|00945|jsonrpc|WARN|tcp:xx.yy.zz.26:41880: send error: Connection reset by peer
  ctl03-ovn-sb-db.log:2022-04-19T12:30:27.325Z|00947|jsonrpc|WARN|tcp:xx.yy.zz.26:41892: send error: Connection reset by peer
  ctl03-ovn-sb-db.log:2022-04-19T12:30:27.327Z|00949|jsonrpc|WARN|tcp:xx.yy.zz.26:41884: send error: Connection reset by peer
  ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00951|jsonrpc|WARN|tcp:xx.yy.zz.25:40260: send error: Connection timed out
  ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00953|jsonrpc|WARN|tcp:xx.yy.zz.25:40264: send error: Connection timed out
  ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00955|jsonrpc|WARN|tcp:xx.yy.zz.24:37440: send error: Connection timed out
  ctl03-ovn-sb-db.log:2022-04-19T12:31:49.244Z|00957|jsonrpc|WARN|tcp:xx.yy.zz.24:37442: send error: Connection timed out
  ctl03-ovn-sb-db.log:2022-04-19T12:31:49.245Z|00959|jsonrpc|WARN|tcp:xx.yy.zz.24:37446: send error: Connection timed out
  ctl03-ovn-sb-db.log:2022-04-19T12:32:01.533Z|01001|jsonrpc|WARN|tcp:xx.yy.zz.67:57586: send error: Connection timed out

  
  2022-04-19 12:30:08.898 27 INFO neutron.db.ovn_revision_numbers_db [req-7fcfdd74-482d-46b2-9f76-07190669d76d ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 - default default] Successfully bumped revision number for resource be178a9a-26d7-4bf0-a4e8-d206a6965205 (type: ports) to 1

  2022-04-19 12:30:09.644 27 INFO neutron.db.ovn_revision_numbers_db
  [req-a8278418-3ad9-450c-89bb-e7a5c1c0a06d
  a9864cd890224c079051b3f56021be64 72db34087b9b401d842b66643b647e16 -
  default default] Successfully bumped revision number for resource
  be178a9a-26d7-4bf0-a4e8-d206a6965205 (type: ports) to 2

  
  2022-04-19 12:30:10.235 27 INFO neutron.wsgi [req-571b53cc-ca04-46f7-89f9-fdf8e5931f4c a9864cd890224c079051b3f56021be64 72db34087b9b401d842b66643b647e16 - default default] xx.yy.zz.68,xx.yy.zz.26 "GET /v2.0/ports?tenant_id=9d3ae9a7b121488285203b0fdeabc3a3&device_id=7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 HTTP/1.1" status: 200  len: 1081 time: 0.0363808

  2022-04-19 12:30:10.395 25 INFO
  nova.api.openstack.compute.server_external_events
  [req-d144458a-ca21-4e92-b5be-4f589e118d8c
  4688fc44551b45c6a761c9c0351e76a8 72db34087b9b401d842b66643b647e16 -
  default default] Creating event network-
  changed:be178a9a-26d7-4bf0-a4e8-d206a6965205 for instance
  7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 on cmp-ucs-01-05.poc.example.com

  
  2022-04-19 12:30:10.402 27 INFO neutron.notifiers.nova [-] Nova event response: {'name': 'network-changed', 'server_uuid': '7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34', 'tag': 'be178a9a-26d7-4bf0-a4e8-d206a6965205', 'status': 'completed', 'code': 200}

  2022-04-19 12:33:01.497 34 INFO neutron.db.ovn_revision_numbers_db
  [req-82f3d4fe-1276-4918-86d3-55cc42ca2816 - - - - -] Successfully
  bumped revision number for resource
  be178a9a-26d7-4bf0-a4e8-d206a6965205 (type: ports) to 3

  COMPUTE-NODES:

  ovs-vswitchd.log:2022-04-19T12:30:10.743Z|08415|bridge|INFO|bridge br-int: added interface tapbe178a9a-26 on port 874
  ovn-controller.log:2022-04-19T12:30:11.251Z|02356|binding|INFO|Claiming lport be178a9a-26d7-4bf0-a4e8-d206a6965205 for this chassis.
  ovn-controller.log:2022-04-19T12:30:11.251Z|02357|binding|INFO|be178a9a-26d7-4bf0-a4e8-d206a6965205: Claiming fa:16:3e:8f:3b:47 1.80.1.254

  nova-compute.log:2022-04-19 12:30:10.672 8 INFO os_vif
  [req-2c8b5f82-ce4a-4aa7-9f0a-d346ee210ffb
  ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 -
  default default] Successfully plugged vif
  VIFOpenVSwitch(active=False,address=fa:16:3e:8f:3b:47,bridge_name='br-
  int',has_traffic_filtering=True,id=be178a9a-26d7-4bf0-a4e8-d206a6965205,network=Network(5dd2512b-56f8-4e04-8623-971a633a76aa),plugin='ovs',port_profile=VIFPortProfileOpenVSwitch,preserve_on_delete=False,vif_name='tapbe178a9a-26')

  ovs-vswitchd.log:2022-04-19T12:35:11.302Z|08448|bridge|INFO|bridge br-int: deleted interface tapbe178a9a-26 on port 874
  ovn-controller.log:2022-04-19T12:35:11.307Z|02380|binding|INFO|Releasing lport be178a9a-26d7-4bf0-a4e8-d206a6965205 from this chassis.

  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [req-2c8b5f82-ce4a-4aa7-9f0a-d346ee210ffb ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 - default default] [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Failed to
   allocate network(s): nova.exception.VirtualInterfaceCreateException: Virtual Interface creation failed
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Traceback (most recent call last):
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 7260, in _create_guest_with_network
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     post_xml_callback=post_xml_callback)
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/usr/lib64/python3.6/contextlib.py", line 88, in __exit__
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     next(self.gen)
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/compute/manager.py", line 479, in wait_for_instance_event
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     actual_event = event.wait()
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/event.py", line 125, in wait
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     result = hub.switch()
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/hubs/hub.py", line 313, in switch
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     return self.greenlet.switch()
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] eventlet.timeout.Timeout: 300 seconds
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] 
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] During handling of the above exception, another exception occurred:
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] 
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Traceback (most recent call last):
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/compute/manager.py", line 2402, in _build_and_run_instance
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     accel_info=accel_info)
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 4225, in spawn
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     cleanup_instance_disks=created_disks)
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]   File "/var/lib/kolla/venv/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 7283, in _create_guest_with_network
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34]     raise exception.VirtualInterfaceCreateException()
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] nova.exception.VirtualInterfaceCreateException: Virtual Interface creation failed
  2022-04-19 12:35:11.842 8 ERROR nova.compute.manager [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] 
  2022-04-19 12:35:11.844 8 ERROR nova.compute.manager [req-2c8b5f82-ce4a-4aa7-9f0a-d346ee210ffb ff1516be452b4b939314bf3864a63f35 9d3ae9a7b121488285203b0fdeabc3a3 - default default] [instance: 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34] Build of 
  instance 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 aborted: Failed to allocate the network(s), not rescheduling.: nova.exception.BuildAbortException: Build of instance 7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34 aborted: Failed to allocate the networ
  k(s), not rescheduling.

  
  CONTROL:

  2022-04-19 12:35:11.330 25 INFO
  neutron.plugins.ml2.drivers.ovn.mech_driver.mech_driver
  [req-2b4d10b1-3a7a-4683-97df-990259705b46 - - - - -] OVN reports
  status down for port: be178a9a-26d7-4bf0-a4e8-d206a6965205

  2022-04-19 12:35:12.524 23 WARNING neutron.notifiers.nova [-] Nova
  event: {'server_uuid': '7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34', 'name':
  'network-vif-deleted', 'tag': 'be178a9a-26d7-4bf0-a4e8-d206a6965205',
  'status': 'failed', 'code': 422} returned with failed status

  /var/log/kolla/neutron/neutron-server.log:2022-04-19 12:35:13.016 25
  WARNING neutron.notifiers.nova [-] Nova event: {'server_uuid':
  '7560fbb7-3ec7-41ef-b7a5-5e955ca4ff34', 'name': 'network-vif-plugged',
  'status': 'failed', 'tag': 'be178a9a-26d7-4bf0-a4e8-d206a6965205',
  'code': 422} returned with failed status

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Follow ups

[Bug 1969592] Re: [OVN] Frequent DB leader changes causes 'VIF creation failed' on nova side
From: yatin, 2023-07-18