Open Stack

Howdy all,

TL;DR: I have a question, does the Telemetry service (or any other 
service) still make use of the server usage audit log API in Nova [1]?

Recently I was investigating customer issues where the nova.task_log 
database table grows infinitely and is never cleaned up [2]. I asked 
about it today in #openstack-nova [3] and Matt Riedemann explained that 
the API is toggled via config option [4] and that the Telemetry service 
is/was the consumer of the API.

I found through code inspection that there are no methods for deleting 
nova.task_log records and am trying to determine what is the best way 
forward for handling cleanup. Matt mentioned the possibility of 
deprecating the server usage audit log API altogether, which we might be 
able to do if no one is using it anymore.

So, I was thinking:

* If Telemetry is no longer using the server usage audit log API, we 
deprecate it in Nova and notify deployment tools to stop setting 
[DEFAULT]/instance_usage_audit = true to prevent further creation of 
nova.task_log records and recommend manual cleanup by users

or

* If Telemetry is still using the server usage audit log API, we create 
a new 'nova-manage db purge_task_log --before <date>' (or similar) 
command that will hard delete nova.task_log records before a specified 
date or all if --before is not specified

Can anyone shed any light on whether Telemetry, or any other service, 
still uses the server usage audit log API in Nova? Would we be able to 
deprecate it? If we can't, what do you think of the nova-manage command 
idea?

I would appreciate hearing your thoughts about it.

Cheers,
-melanie

[1] 
https://docs.openstack.org/api-ref/compute/#server-usage-audit-log-os-instance-usage-audit-log
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1726256
[3] 
http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23openstack-nova.2019-09-06.log.html#t2019-09-06T14:10:38
[4] 
https://docs.openstack.org/nova/latest/configuration/config.html#DEFAULT.instance_usage_audit