[Neutron] neutron.db.agentschedulers_db ERROR in logs after ban 2 DHCP and 2 L3 agents

[Alexander Gromov]

MOS 9.2 snapshot #655

During running the test for verification https://bugs.launchpad.net/mos/+bug/1493754 bug the following error has been found in neutron server logs:
http://paste.openstack.org/show/592899/

2 configurations have been checked:
1) 3 controllers, 2 computes, 1 cinder node, Neutron VLAN
2) 3 controllers+mongo, 2 computes+cinder, Neutron VLAN DVR, Ceilometer, Sahara

Steps to reproduce:
1. Update quotas for creation a lot of networks
2. Create 50 networks, subnets, launch and terminate instanсe
3. Ban two dhcp agents related to the first network
4. Ban two l3 agents
5. Check /var/log/neutron/server.log file for errors.

Expected results:
Only Quota errors exist in neutron server logs (as neutron can't create more than about 34 networks).

Actual error:
neutron.db.agentschedulers_db error is found in /var/log/neutron/server.log on one controller.

The following script can be used for reproducing this situation:
http://paste.openstack.org/show/592900/

It was notices that the bug can be reproduced only after creating networks more than quota value.
After creation only OverLimit logs exist, but after banning agents db log also appears on ONE controller.

[Oleg Bondarev (obondarev)]

I believe this is a race between neutron servers to delete agent-to-net binding. Should not affect functionality, only traces in logs.

[Alexander Ignatov (aignatov)]

Moving bug to 10.0 because it's low.

[Oleg Bondarev (obondarev)]

Marking as won't fix since not affecting functionality