Open Stack

Le 19/08/2014 14:51, Sylvain Bauza a écrit :
> Hi,
>
> As it was also stated in 
> http://www.stillhq.com/openstack/juno/000012.html, we expect to finish 
> the prerequisites for Scheduler split by Juno. That requires to merge 
> two blueprints, one with the spec validated but patches still under 
> review [1] and one with the spec still subject to debates [2]
>
>
> During this cycle, we discussed a lot how to update Scheduler with 
> Compute Node stats, and the proposal we made (with a +2 on the spec) 
> was to make use of Extensible Resource Tracker [3] to make that work 
> easily without having to create new DB or Objects fields.
>
> That said, it seems Extensible Resource Tracker (ERT) is still subject 
> to discussions [4], where a revert change has been proposed [5]
>
> I can understand the concerns raised by that, but that's unfortunate 
> that we discuss if ERT is good or not by 1 week before Feature 
> Proposal Freeze, which will happen this Thursday. Indeed, while the 
> changes have been proposed now some weeks ago, it requires to create 
> new patches by 2 days in order to remove ERT as a dependency from the 
> patches. IIUC, removing ERT means, with the concern of scheduler 
> split, to create a new DB compute_node field and a new ComputeNode 
> Object attribute for each resource (aggregate, instance, flavor) 
> related to the host : that will generate more work and while the 
> interface will be quite good (one field for one type), it will have 
> huge payload (one ComputeNode version more, migrations etc.)
>
> In that condition, I can't hardly see how we can reach the target of 
> merging all the bits by Juno. That's why I'm coming back to you, 
> Nova-ists, to know your opinion and what kind of things you would like.
>
>
> Yeah, I know that's life and life can be hard, but I'm just advocating 
> advices for getting all of your attention.
>
>

So, we held Gantt meeting today, and minutes are here 
http://eavesdrop.openstack.org/meetings/gantt/2014/gantt.2014-08-19-15.00.html
The concern I raised above has been heavily discussed there and we ended 
up deciding that we need to clean up the interfaces in between Scheduler 
and Resource Tracker (ie. cleary identify an API for modeling resources 
sent to Scheduler, not a bare JSON blob containing nested dicts)

So, long story short, we identified PoC from Jay Pipes [6] as a good 
starting point for the resource models and classes that would contain 
the resource usage. Jay and I volunteered for porting that model into 
Nova soon and see how it will integrate with existing.
That means that the validated effort on a scheduler library 
(bp/scheduler-lib, here [1]) are still considered for Juno (and need to 
be reviewed), while patches related to [2] (bp/isolate-scheduler-db) are 
considered on-hold until we identify the proper way, as said previously.

On the other hand, ERT discussion is decoupled from the scheduler split 
discussion and will be delayed until Extensible Resource Tracker owner 
(Paul Murray) is back from vacation.
In the mean time, we're considering new patches using ERT as 
non-acceptable, at least until a decision is made about ERT.

-Sylvain

[6] https://review.openstack.org/#/c/103598/

> -Sylvain
>
>
> [1] https://review.openstack.org/82778 and 
> https://review.openstack.org/104556
> [2] 
> https://review.openstack.org/#/q/status:open+topic:bp/isolate-scheduler-db,n,z
> [3] https://review.openstack.org/#/c/109643/
> [4] 
> http://lists.openstack.org/pipermail/openstack-dev/2014-August/042709.html
> [5] https://review.openstack.org/115218
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev