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Bug 1850147

Summary: [ovn] Agent liveness checks create too many writes into OVN db
Product: Red Hat OpenStack Reporter: Lucas Alvares Gomes <lmartins>
Component: python-networking-ovnAssignee: Lucas Alvares Gomes <lmartins>
Status: CLOSED ERRATA QA Contact: Eduardo Olivares <eolivare>
Severity: high Docs Contact:
Priority: high    
Version: 16.0 (Train)CC: apevec, ekuris, jlibosva, lhh, majopela, scohen
Target Milestone: z4Keywords: Triaged
Target Release: 16.2 (Train on RHEL 8.4)   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: python-networking-ovn-7.2.1-0.20200626164637.4492ff3.el8ost Doc Type: No Doc Update
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-09-15 07:08:44 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Lucas Alvares Gomes 2020-06-23 15:28:12 UTC 
Reported at: https://bugs.launchpad.net/neutron/+bug/1883554

Every time the agent liveness check is triggered (via API or periodically every agent_down_time / 2 seconds), there are a lot of writes into the SB database on the Chassis table.
These writes triggers recomputation on ovn-controller running in all nodes having a considerable performance hit, especially under stress.

After this commit was merged [0] we avoided bumping nb_cfg too frequently but still we're performing writes into the Chassis table to often, from all the workers.

We should use the same logic in [1] to avoid writes that have happened recently.

[0] https://opendev.org/openstack/neutron/commit/647b7f63f9dafedfa9fb6e09e3d92d66fb512f0b
[1] https://github.com/openstack/neutron/blob/4de18104ae88a835544cefbf30c878aa49efc31f/neutron/plugins/ml2/drivers/ovn/mech_driver/mech_driver.py#L1075
Comment 12 errata-xmlrpc 2021-09-15 07:08:44 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Red Hat OpenStack Platform (RHOSP) 16.2 enhancement advisory), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2021:3483