<div dir="ltr"><br><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Jul 7, 2014 at 8:02 AM, Daniel P. Berrange <span dir="ltr"><<a href="mailto:berrange@redhat.com" target="_blank">berrange@redhat.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="">On Mon, Jul 07, 2014 at 02:38:57PM +0000, Dugger, Donald D wrote:<br>
> Well, my main thought is that I would prefer to see the gantt split<br>
> done sooner rather than later. The reality is that we've been trying<br>
> to split out the scheduler for months and we're still not there. Until<br>
> we bite the bullet and actually do the split I'm afraid we'll still be<br>
> here discussing the `best` way to do the split at the K & L summits<br>
> (there's a little bit of `the perfect is the enemy of the good' happening<br>
> here). With the creation of the client library we've created a good<br>
> seam to split out the scheduler, let's do the split and fix the remaining<br>
> problems (aggregates and instance group references).<br>
<br>
> To address some specific points:<br>
<br>
</div><div class="">> 2) We won't get around to creating parity between gantt and nova. Gantt<br>
> will never be the default scheduler until it has complete parity with the<br>
> nova scheduler, that should give us sufficient incentive to make sure we<br>
> achieve parity as soon as possible. </div></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="">
<br>
</div>Although it isn't exactly the same situation, we do have history with<br>
Neutron/nova-network showing that kind of incentive to be insufficient<br>
to make the work actually happen. If Gantt remained a subset of features<br>
of the Nova scheduler, this might leave incentive to address the gaps,<br>
but I fear that other unrelated features will be added to Gantt that<br>
are not in Nova, and then we'll be back in the Neutron situation pretty<br>
quickly where both options have some features the other option lacks.<br>
<div class=""><br>
> 3) The split should be done at the beginning of the cycle. I don't<br>
> see a need for that, we should do the split whenever we are ready.<br>
> Since gantt will be optional it shouldn't affect release issues with<br>
> nova and the sooner we have a separate tree the sooner people can test<br>
> and develop on the gantt tree.<br>
<br>
</div>If we're saying Gantt is optional, this implies the existing Nova code<br>
is remaining. This seems to leave us with the neutron/nova-network<br>
situation again of maintaining two code bases again, and likely the<br>
people who were formerly fixing the bugs in nova scheduler codebase<br>
would be focused on gantt leaving the nova code to slowly bitrot.<br></blockquote><div><br></div><div><br></div><div>I agree with Daniel, we should not make Gantt optional otherwise we risk ending up in a neutron/nova-network scenario. IMHO the workflow from the consumers point of view should be something along the lines of:</div>
<div><br></div><div>* In release X, nova-scheduler is deprecated and will be removed in N cycles with Gantt as the default scheduler (along with a robust migration strategy)</div><div>* In release X+N we delete nova-scheduler</div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="im HOEnZb"><br>
Regards,<br>
Daniel<br>
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