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From 杨逸帆Steven ...@legato.ninja>
Subject Re: Why return NULL_ASSIGNMENT when one app can not assign to this leaf queue?
Date Tue, 24 Feb 2015 01:22:46 GMT
Hi Da,

Thanks for your explain. Now I understand it better. As for the
reservation, can I simply comment out the function 'reserve' in LeafQueue
for capacity scheduler?

Sincerely,
Steven


On Tue, Feb 24, 2015 at 4:57 AM, Wangda Tan <wheeleast@gmail.com> wrote:

> Hi Steven,
> For now, CapacityScheduler trying to solve is large batch job, it allocates
> resource in FIFO manner, and adding capacity limits, etc. So if a job
> submit later cannot get resource before previous job get satisfied. This is
> to make big batch job can get resource quickly and finish quickly.
>
> I don't think there's a way to disable reservation.
>
> HTH,
> Wangda
>
> On Mon, Feb 23, 2015 at 3:37 AM, 杨逸帆Steven <me@legato.ninja> wrote:
>
> > HI,
> >
> > I am learning Yarn source code, and have this confussion.
> >
> > In the assignContainers@LeafQueue.java, yarn will iterate all active
> > applications and try to do the schedule work. however, I notive if one
> > application's require is over queue limit, the function will return but
> not
> > break.
> >
> > Say I have app#2 needs 500mb, and next app# needs 300mb. The queue now
> has
> > only 400mb available left, so when app#2 canAssignToThisQueue fails,
> > function return and leaves app#3 without schedule. And in this case,
> app#3
> > is able to run.
> >
> > So, what is the reason to Return here?
> >
> >
> > Thank you.
> >
> > P.S can I disable reservation? and how to do that?
> >
> > Sincerely,
> > Steven
> >
>

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