Open Stack

On Apr 17, 2014, at 4:26 PM, Joshua Harlow <harlowja at yahoo-inc.com> wrote:

> Just an honest question (no negativity intended I swear!).
> 
> If a configuration option exists and only works with a patched eventlet why is that option an option to begin with? (I understand the reason for the patch, don't get me wrong).
> 

Right, it’s a valid question. This feature has existed one way or another in nova for quite a while. Initially the implementation in nova was wrong. I did not know that eventlet was also broken at the time, although I discovered it in the process of fixing nova’s code. I chose to leave the feature because it’s something that we absolutely need long term, unless you really want to live with DB calls blocking the whole process. I know I don’t. Unfortunately the bug in eventlet is out of our control. (I made an attempt at fixing it, but it’s not 100%. Eventlet folks currently have an alternative up that may or may not work… but certainly is not in a release yet.)  We have an outstanding bug on our side to track this, also.

The below is comparing apples/oranges for me.

- Chris


> Most users would not be able to use such a configuration since they do not have this patched eventlet (I assume a newer version of eventlet someday in the future will have this patch integrated in it?) so although I understand the frustration around this I don't understand why it would be an option in the first place. An aside, if the only way to use this option is via a non-standard eventlet then how is this option tested in the community, aka outside of said company?
> 
> An example:
> 
> If yahoo has some patched kernel A that requires an XYZ config turned on in openstack and the only way to take advantage of kernel A is with XYZ config 'on', then it seems like that’s a yahoo only patch that is not testable and useable for others, even if patched kernel A is somewhere on github it's still imho not something that should be a option in the community (anyone can throw stuff up on github and then say I need XYZ config to use it).
> 
> To me non-standard patches that require XYZ config in openstack shouldn't be part of the standard openstack, no matter the company. If patch A is in the mainline kernel (or other mainline library), then sure it's fair game.
> 
> -Josh
> 
> From: Chris Behrens <cbehrens at codestud.com>
> Reply-To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org>
> Date: Thursday, April 17, 2014 at 3:20 PM
> To: OpenStack Development Mailing List <openstack-dev at lists.openstack.org>
> Subject: [openstack-dev] oslo removal of use_tpool conf option
> 
>> 
>> I’m going to try to not lose my cool here, but I’m extremely upset by this.
>> 
>> In December, oslo apparently removed the code for ‘use_tpool’ which allows you to run DB calls in Threads because it was ‘eventlet specific’. I noticed this when a review was posted to nova to add the option within nova itself:
>> 
>> https://review.openstack.org/#/c/59760/
>> 
>> I objected to this and asked (more demanded) for this to be added back into oslo. It was not. What I did not realize when I was reviewing this nova patch, was that nova had already synced oslo’s change. And now we’ve released Icehouse with a conf option missing that existed in Havana. Whatever projects were using oslo’s DB API code has had this option disappear (unless an alternative was merged). Maybe it’s only nova.. I don’t know.
>> 
>> Some sort of process broke down here.  nova uses oslo.  And oslo removed something nova uses without deprecating or merging an alternative into nova first. How I believe this should have worked:
>> 
>> 1) All projects using oslo’s DB API code should have merged an alternative first.
>> 2) Remove code from oslo.
>> 3) Then sync oslo.
>> 
>> What do we do now? I guess we’ll have to back port the removed code into nova. I don’t know about other projects.
>> 
>> NOTE: Very few people are probably using this, because it doesn’t work without a patched eventlet. However, Rackspace happens to be one that does. And anyone waiting on a new eventlet to be released such that they could use this with Icehouse is currently out of luck.
>> 
>> - Chris
>> 
>> 

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