Description of problem:
Client recently updated their OSP13 from z10 to z12. They are using OVN in their environment.

They are spawning instances through heat templates with Tower and sometimes (currently frequently) the instance is spawned, get an ip through dhcp, but the next steps in the deployment where it curls an internal URL fails. It is being tried for like 20-30 minutes and the curl keep failing. After 30 minutes the curl is not tried anymore but it looks like you can access the outside network.

ovn-controller.log from the compute node around the time the port was created:
2020-10-23T06:07:09.381Z|18828|timeval|WARN|Unreasonably long 40122ms poll interval (40016ms user, 10ms system)
2020-10-23T06:07:09.381Z|18829|timeval|WARN|faults: 10388 minor, 0 major
2020-10-23T06:07:09.381Z|18830|timeval|WARN|context switches: 0 voluntary, 24 involuntary

From on of the controller:
2020-10-23T06:06:29.937Z|25829|timeval|WARN|Unreasonably long 1140ms poll interval (1136ms user, 0ms system)
2020-10-23T06:06:29.937Z|25830|timeval|WARN|faults: 8 minor, 0 major
2020-10-23T06:06:29.937Z|25831|timeval|WARN|context switches: 0 voluntary, 3 involuntary
2020-10-23T06:07:09.154Z|25832|timeval|WARN|Unreasonably long 37364ms poll interval (37263ms user, 11ms system)
2020-10-23T06:07:09.154Z|25833|timeval|WARN|faults: 2337 minor, 0 major
2020-10-23T06:07:09.154Z|25834|timeval|WARN|context switches: 0 voluntary, 69 involuntary
2020-10-23T06:07:09.154Z|25835|poll_loop|INFO|wakeup due to [POLLIN] on fd 20 (<->/var/run/openvswitch/br-int.mgmt) at lib/stream-fd.c:157 (97% CPU usage)
2020-10-23T06:07:09.154Z|25836|poll_loop|INFO|wakeup due to [POLLIN] on fd 19 (10.10.183.12:59198<->10.10.183.11:6642) at lib/stream-fd.c:157 (97% CPU usage)
2020-10-23T06:07:09.171Z|25837|poll_loop|INFO|wakeup due to 0-ms timeout at tcp:10.10.183.11:6642 (97% CPU usage)
2020-10-23T06:07:46.291Z|25838|timeval|WARN|Unreasonably long 37119ms poll interval (37028ms user, 2ms system)
2020-10-23T06:07:46.291Z|25839|timeval|WARN|faults: 1814 minor, 0 major
2020-10-23T06:07:46.291Z|25840|timeval|WARN|context switches: 0 voluntary, 80 involuntary
2020-10-23T06:07:46.291Z|25841|coverage|INFO|Dropped 2 log messages in last 77 seconds (most recently, 37 seconds ago) due to excessive rate
2020-10-23T06:07:46.291Z|25842|coverage|INFO|Skipping details of duplicate event coverage for hash=4bbd7269
2020-10-23T06:07:46.291Z|25843|poll_loop|INFO|wakeup due to [POLLIN] on fd 20 (<->/var/run/openvswitch/br-int.mgmt) at lib/stream-fd.c:157 (99% CPU usage)
2020-10-23T06:07:46.291Z|25844|poll_loop|INFO|wakeup due to [POLLIN] on fd 19 (10.10.183.12:59198<->10.10.183.11:6642) at lib/stream-fd.c:157 (99% CPU usage)
2020-10-23T06:07:47.178Z|25845|poll_loop|INFO|wakeup due to [POLLIN] on fd 20 (<->/var/run/openvswitch/br-int.mgmt) at lib/stream-fd.c:157 (99% CPU usage)
2020-10-23T06:07:53.810Z|25846|timeval|WARN|Unreasonably long 1056ms poll interval (1052ms user, 0ms system)
2020-10-23T06:07:53.810Z|25847|timeval|WARN|context switches: 0 voluntary, 13 involuntary

From nb.log we see these every minutes (before and after instance creation):
2020-10-23T06:06:52.280Z|45205|socket_util|ERR|Dropped 39 log messages in last 58 seconds (most recently, 3 seconds ago) due to excessive rate
2020-10-23T06:06:52.280Z|45206|socket_util|ERR|6641:10.10.183.11: bind: Cannot assign requested address
2020-10-23T06:06:52.280Z|45207|ovsdb_jsonrpc_server|ERR|Dropped 39 log messages in last 58 seconds (most recently, 3 seconds ago) due to excessive rate
2020-10-23T06:06:52.280Z|45208|ovsdb_jsonrpc_server|ERR|ptcp:6641:10.10.183.11: listen failed: Cannot assign requested address

And sb also every minutes:
2020-10-23T06:07:01.932Z|45543|socket_util|ERR|Dropped 34 log messages in last 59 seconds (most recently, 2 seconds ago) due to excessive rate
2020-10-23T06:07:01.932Z|45544|socket_util|ERR|6642:10.10.183.11: bind: Cannot assign requested address
2020-10-23T06:07:01.932Z|45545|ovsdb_jsonrpc_server|ERR|Dropped 34 log messages in last 59 seconds (most recently, 2 seconds ago) due to excessive rate
2020-10-23T06:07:01.932Z|45546|ovsdb_jsonrpc_server|ERR|ptcp:6642:10.10.183.11: listen failed: Cannot assign requested address

Interestingly is that the IP they are trying to curl is 10.10.x.x so maybe its related to this ? Maybe not since those are there all the time.

sosreport from all 3 controllers, 1 compute nodes and the ovn databases are uploaded.
I will put details about that one instance we are currently investigating in the next private comment.

I need your help to understand why sometimes the network is very slow.

Thank you.


Version-Release number of selected component (if applicable):
OSP13 z12 
Latest containers

How reproducible:
Frequently right now. Some days no issues. Look random.

Steps to Reproduce:
1. Spawn instances
2. 
3.

Actual results:
There is a huge delay for the instance to be able to reach the outside network

Expected results:
Instance can reach the outside network "as soon" as the ip is allocated (what you would expect)

Additional info:
sosreports and ovn databases are available.