[openstack-dev] [Gantt] Looking for some answers...

Dugger, Donald D donald.d.dugger at intel.com
Mon Jan 6 19:50:27 UTC 2014

Pretty much what Vish said.

In re: History.  I think this was the right way, these scheduler files didn't just spring up from nowhere, maintaining the history is a good thing.  Even when this becomes a separate service knowing where the files came from is a good thing.

In re: Changes to the current scheduler - I intend to track the nova tree and port over any changes to the nova scheduler code into the gantt tree.  Hopefully, by the time the gantt code has diverged enough that this becomes a burden we will have deprecated the nova scheduler code and have moved to gantt.

Don Dugger
"Censeo Toto nos in Kansa esse decisse." - D. Gale
Ph: 303/443-3786

-----Original Message-----
From: Vishvananda Ishaya [mailto:vishvananda at gmail.com] 
Sent: Monday, January 6, 2014 12:31 PM
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [Gantt] Looking for some answers...

On Jan 6, 2014, at 11:02 AM, Jay Pipes <jaypipes at gmail.com> wrote:

> Hello Stackers,
> I was hoping to get some answers on a few questions I had regarding 
> the Gantt project [1]. Specifically, here are my queries:
> 1) Why was Nova forked to the http://github.com/openstack/gantt 
> repository? Forking Nova just to then remove a bunch of code that 
> doesn't relate to the scheduler code means that we bring 10K+ commits 
> and a git history along with the new project... this seems to be the 
> wrong origin for a project the aims to be a separate service. There's 
> a reason that Cinder and Neutron didn't start out as a fork of Nova, 
> after all...

Authorship history is nice, but this does seem a bit excessive. The cinder strategy of a single squashed fork would have been/still be fine I'm sure.
> 2) Why is Gantt in the /openstack GitHub organization? Wouldn't the 
> /stackforge organization be more appropriate for a project that isn't 
> integrated? If I understand some of the backstory behind Gantt, the 
> idea was to create a scheduler service from the existing Nova 
> scheduler code in order to "complete the work sometime in our lifetime".
> While I understand the drive to start with something that already 
> exists and iterate over it, I don't understand why the project went 
> right into the /openstack organization instead of following the 
> /stackforge processes for housing code that bakes and gets iterated on 
> before proposing for incubation. Some explanation would be great here.

This is split-out of existing code so it is following the same path as cinder. The goal is to deprecate the existing nova scheduler in I. It currently a new project under the nova program I believe.

> 3) Where is feature planning happening for Gantt? The Launchpad site 
> for Gantt [2] is empty. Furthermore, there are a number of blueprints 
> for improving the Nova scheduler, notably the no-db-scheduler 
> blueprint [3], which even has code submitted for it and is targeted to 
> Icehouse-2. How are improvements like this planned to be ported (if at all) to Gantt?

Not sure about the launchpad site. There is a regular scheduler group meeting and as I understand it the hope will be to do the no-db-scheduler blueprint.
There was quite a bit of debate on whether to do the no-db-scheduler stuff before or after the forklift and I think the consensus was to do the forklift first.

> 4) Is the aim of Gantt to provide a RESTful HTTP API in addition to 
> the RPC-based API that the existing Nova scheduler exposes?

In the short term the plan is to just replicate the rpc api, but I think a REST api will be considered long term.


> Thanks much in advance for answers, and apologies if these have been 
> answered before and I missed the ML threads or design summit 
> discussions.
> Best,
> -jay
> [1] https://github.com/openstack/gantt/
> [2] http://blueprints.launchpad.net/gantt
> [3] https://blueprints.launchpad.net/nova/+spec/no-db-scheduler
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