Re: [HTCondor-users] Negotiation with partitionable slots

[Mathieu Bahin <mathieu.bahin@xxxxxxxxxxxxxxx>]

Hi Steffen,

Thanks for your answer (and yes it was a typo).

Your formula is interesting too. Though I'm not sure I made myself clear
on my main question...
I'll try to illustrate it with a very simple example.

Let's have a cluster of 4 nodes: 2 "small" with 5 CPUs and 2 "big" with
10 CPUs. If I set NEGOTIATOR_PRE_JOB_RANK = floor(TotalCpus / 10) *
-10000000
then the small nodes should be assigned first to jobs (if matching the
requirements).
But if I run 6 jobs requesting 1 CPU each, in the negotiation cycle, the
4 nodes of the cluster will advertise 1 free slot each (the one
gathering the free resources on each node) and so only 2 jobs will be
assigned to the small nodes, then 2 others will be assigned to the big
ones and finally the 2 last will be assigned to the small nodes during
the next negotiation cycle.

Am I right? At least that's what I understand is happening on our
cluster with this new formula. Though what I would like in this
situation is the 6 jobs to be assigned to the small nodes.

Cheers,
Mathieu

On 27/04/17 19:00, htcondor-users-request@xxxxxxxxxxx wrote:
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>    1. Negotiation with partitionable slots (Mathieu Bahin)
>    2. Re: Negotiation with partitionable slots (Steffen Grunewald)
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> ----------------------------------------------------------------------
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> Message: 1
> Date: Thu, 27 Apr 2017 09:23:16 +0200
> From: Mathieu Bahin <mathieu.bahin@xxxxxxxxxxxxxxx>
> To: htcondor-users@xxxxxxxxxxx
> Subject: [HTCondor-users] Negotiation with partitionable slots
> Message-ID: <59019C64.1000805@xxxxxxxxxxxxxxx>
> Content-Type: text/plain; charset=utf-8
>
> Hi,
>
> Our cluster, configured with partitionable slots and having very
> heterogeneous nodes, is being more loaded for a few months and we are
> facing a new issue: it's complicated for a user to run a job requesting
> big CPUs and/or memory.
>
> Ideally, we would have liked to have the smallest machines first filled
> up to ~80% (not to overload them when there is still space anywhere
> else) in order to leave free a few of the biggest machines when possible.
>
> We designed the NEGOCIATOR_JOB_POST_RANK value to something like that:
> (RemoteOwner =!= UNDEFINED) * ((floor(TotalCpus / 10) * -10000000) +
> KFlops - 1.0e10 * (Offline =?= True))
> Our nodes are then divided into 4 classes (our biggest node has 32
> CPUs), the one having less than 10 CPUs are now prioritary and within
> classes, the most powerful nodes comes first (with Kflops).
>
> Though, if we run a few dozens of jobs, from what I noted, the priority
> order is satisfying but only one job is allocated to the nodes of the
> more priority classes (I guess because with the partitionable slots,
> nodes only advertise one big free slot for one negotiation cycle) and
> the next ones are allocated, one by one also, to the less priority nodes.
> How can we do for several jobs really filling the highest priority nodes
> before considering the others?
>
> Cheers,
> Mathieu
>

-- 
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| Mathieu Bahin
| IE CNRS
|
| Institut de Biologie de l'Ecole Normale Supérieure (IBENS)
| Biocomp team
| 46 rue d'Ulm
| 75230 PARIS CEDEX 05
| 01.44.32.23.56
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