cert-mon: uncaught exceptions within audit greenpool are not logged

[Manoel Benedito Neto]

Brief Description
-----------------
It was difficult to catch an uncaught exception within the subcloud audit greenpool thread was not logged.

We need to ensure the greenpool is properly hooked into logging subsystem.

Severity
--------
Minor

Steps to Reproduce
------------------
Create an uncaught exception in certificate_mon_manager.py:do_subcloud_audit()

Expected Behavior
-----------------
We should see a traceback in the log file.

Actual Behavior
---------------
Silence

Reproducibility
---------------
Reproducible

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
unknown

Last Pass
---------
unknown

Timestamp/Logs
--------------
2021-12-08T15:08:09.000 controller-0 cert-mon: info 2021-12-08 15:08:09.948 175173 INFO sysinv.cert_mon.service [req-6aa5fce8-6d44-4778-8a62-9912460797c9 - - - - -] subcloud845 is online. An online audit is queued
2021-12-08T15:08:09.000 controller-0 cert-mon: info 2021-12-08 15:08:09.950 175173 INFO sysinv.cert_mon.subcloud_audit_queue [req-6aa5fce8-6d44-4778-8a62-9912460797c9 - - - - -] Enqueued: SubcloudAuditData: \{name: subcloud845, audit_count: 1}
2021-12-08T15:08:12.000 controller-0 cert-mon: info 175173 INFO sysinv.cert_mon.certificate_mon_manager [-] Auditing subcloud subcloud845, attempt #1 [qsize: 0]
2021-12-08T15:08:12.000 controller-0 cert-mon: err 175173 ERROR sysinv.cert_mon.utils [-] Cannot find sysinv endpoint for subcloud845
2021-12-08T15:08:12.000 controller-0 cert-mon: info 175173 INFO sysinv.cert_mon.utils [-] api_cmd http://[2620:10a:a001:a114::d00]:8119/v1.0/subclouds/subcloud845
2021-12-08T15:17:21.000 controller-0 cert-mon: info 175173 INFO sysinv.cert_mon.utils [-] api_cmd http://[2620:10a:a001:a114::d00]:8119/v1.0/subclouds/subcloud10

Alarms
------
N/A

Test Activity
-------------
System testing

Workaround
----------
N/A

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/config/+/872700
Committed: https://opendev.org/starlingx/config/commit/51afe1ee79463ea9879380819f901520e1cf9bdd
Submitter: "Zuul (22348)"
Branch: master

commit 51afe1ee79463ea9879380819f901520e1cf9bdd
Author: Manoel Benedito Neto <email address hidden>
Date: Fri Feb 3 15:59:40 2023 -0300

    Add exception clause and logs for subcloud audit

    Added an except clause to log uncaught exceptions that may happen when
    _subcloud_audit function is called.

    Test Plan:
    PASS: In a DX DC system with AIO-SX subcloud offline, observe the log
          exception message and callstack traceback to be thrown on the
          /var/log/cert-mon.log file, as code execution proceeds to
          finally clause in do_subcloud_audit function.
    PASS: In a DX DC system with simplex subcloud online, force an invalid
          subcloud audit item to assume None value. Observe the log
          exception message and callstack traceback to be thrown in the
          /var/log/cert-mon.log file, as code execution proceeds to finally
          clause in do_subcloud_audit function.

    Closes-Bug: 2006136
    Signed-off-by: Manoel Benedito Neto <email address hidden>
    Change-Id: I3e92db11a9339a9637ea036b2c6522a47b4a803f