[Openstack-operators] [openstack-operators][nova] Verbosity of nova scheduler
Alec Hothan (ahothan)
ahothan at cisco.com
Wed Jan 10 07:15:17 UTC 2018
Great to see some interest on trying to improve the log!
+1 on the “no valid host found”, this one should be at the very top of the to-be-fixed list.
Very difficult to troubleshoot filters in lab testing (let alone in production) as there can be many of them. This will get worst with more NFV optimization filters with so many combinations it gets really complex to debug when a VM cannot be launched with NFV optimized flavors. With the scheduler filtering engine, there should be a systematic way to log the reason for not finding a valid host - at the very least the error should display which filter failed as an ERROR (and not as DEBUG).
We really need to avoid deploying with DEBUG log level but unfortunately this is the only way to troubleshoot. Too many debug-level logs are for development debug (meaning pretty much useless in any circumstances – developer forgot to remove before commit of the feature), many errors that should be logged as ERROR but have been logged as DEBUG only.
From: Mikhail Medvedev <mihailmed at gmail.com>
Date: Tuesday, January 9, 2018 at 9:16 AM
To: Piotr Bielak <piotr.bielak at corp.ovh.com>
Cc: "openstack-operators at lists.openstack.org" <openstack-operators at lists.openstack.org>
Subject: Re: [Openstack-operators] [openstack-operators][nova] Verbosity of nova scheduler
On Tue, Jan 9, 2018 at 8:18 AM, Piotr Bielak <piotr.bielak at corp.ovh.com<mailto:piotr.bielak at corp.ovh.com>> wrote:
> Hi! I'm conducting some research about the nova scheduler logs
> verbosity. Did you ever encounter any situation, where you didn't feel
> satisfied with the amount or quality of the logs (at any log level).
> It is known that the nova-scheduler produces hardly any logs at INFO
> level. What are your experiences with the nova-scheduler in production
> environments? What would you like to see in the logs, what isn't printed
> at the moment (maybe some expected log format)?
I am supporting a couple of OpenStack dev clouds and I found in order to solve most operational problems faster I need DEBUG enabled everywhere. In case of scheduler, "No valid host was found" was untractable without the debug messages (as of Mitaka). I need to know what filter ate all the hosts and what values it used for calculations as a minimum.
> Thanks for any help and advice,
> Piotr Bielak
Mikhail Medvedev (mmedvede)
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