Wrong description about minimum value of live_migration_downtime(_delay)

[Takashi Kajinami]

Description
===========
The parameter descriptions say live_migration_downtime_steps and live_migration_downtime_delay are rounded if too small values are given. However actually these parameters have minimum defined and oslo.config does not accept too small values and fail to load the config.

Steps to reproduce
==================
Configure
 [libvirt] live_migration_downtime = 50
 [libvirt] live_migration_downtime_steps =2

Expected result
===============
Actual behavior matches the explanation

Actual result
=============
Actual behavior and its explanation do not match

Environment
===========
N/A

Logs & Configs
==============
N/A

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/nova/+/874061

[Takashi Kajinami (kajinamit)]

I've created a test patch which configures the following settings.

[libvirt]
live_migration_downtime=30
live_migration_downtime_steps=1

https://review.opendev.org/c/openstack/puppet-nova/+/874060/

Now nova-compute crashes during start up with the following traceback.

2023-02-16 08:44:03.163 97402 CRITICAL nova [None req-9143f4ed-2063-4a6c-b665-2adb133725ca - - - - - -] Unhandled error: oslo_config.cfg.ConfigFileValueError: Value for option live_migration_downtime from LocationInfo(location=<Locations.user: (4, True)>, detail='/etc/nova/nova.conf') is not valid: Should be greater than or equal to 100
2023-02-16 08:44:03.163 97402 ERROR nova Traceback (most recent call last):
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_config/cfg.py", line 2716, in _do_get
2023-02-16 08:44:03.163 97402 ERROR nova return (convert(val), alt_loc)
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_config/cfg.py", line 2685, in convert
2023-02-16 08:44:03.163 97402 ERROR nova return self._convert_value(
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_config/cfg.py", line 2813, in _convert_value
2023-02-16 08:44:03.163 97402 ERROR nova return opt.type(value)
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_config/types.py", line 315, in __call__
2023-02-16 08:44:03.163 97402 ERROR nova raise ValueError('Should be greater than or equal to %g' %
2023-02-16 08:44:03.163 97402 ERROR nova ValueError: Should be greater than or equal to 100
2023-02-16 08:44:03.163 97402 ERROR nova
2023-02-16 08:44:03.163 97402 ERROR nova During handling of the above exception, another exception occurred:
2023-02-16 08:44:03.163 97402 ERROR nova
2023-02-16 08:44:03.163 97402 ERROR nova Traceback (most recent call last):
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/bin/nova-compute", line 10, in <module>
2023-02-16 08:44:03.163 97402 ERROR nova sys.exit(main())
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/nova/cmd/compute.py", line 62, in main
2023-02-16 08:44:03.163 97402 ERROR nova service.wait()
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/nova/service.py", line 492, in wait
2023-02-16 08:44:03.163 97402 ERROR nova _launcher.wait()
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_service/service.py", line 388, in wait
2023-02-16 08:44:03.163 97402 ERROR nova status, signo = self._wait_for_exit_or_signal()
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_service/service.py", line 363, in _wait_for_exit_or_signal
2023-02-16 08:44:03.163 97402 ERROR nova self.conf.log_opt_values(LOG, logging.DEBUG)
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_config/cfg.py", line 2611, in log_opt_values
2023-02-16 08:44:03.163 97402 ERROR nova _sanitize(opt, getattr(group_attr, opt_name)))
2023-02-16 08:44:03.163 97402 ERROR nova File "/usr/lib/python3.9/site-packages/oslo_config/cfg.py", line 3161, in __getattr...

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/nova/+/874061
Committed: https://opendev.org/openstack/nova/commit/009ffe4127414af06aff4a7390b436bc89297d08
Submitter: "Zuul (22348)"
Branch: master

commit 009ffe4127414af06aff4a7390b436bc89297d08
Author: Takashi Kajinami <email address hidden>
Date: Thu Feb 16 17:02:22 2023 +0900

    Fix wrong description about minimum values

    The following options have minimum values defined, and too small values
    are not rounded but rejected by oslo.config.

    This change updates the description to explain the actual behavior.

    Closes-Bug: #2007532
    Change-Id: I8d1533ae4b44d4e8f811dce554196f270e25da3e

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 29.0.0.0rc1 release candidate.