Re: [Condor-users] Guiding machine choices for the parallel universe

[Greg Thain <gthain@xxxxxxxxxxx>]

Alan Woodland wrote:
> Hi,
>
> Is there a way to "guide" condor's choice of nodes to satisfy a
> parallel universe job automatically? Basically the cost of
> communication between all nodes in one of my pools is not equal
> because of network topology. Given this I'm looking for a way to make
> the Dedicated Scheduler aware of this and prefer to match nodes that
> are close to each other on the network, but not prevent larger
> parallel jobs using all the machines.
>
> Clearly users could write a requirements =  or rank = line in their
> job submission file, but I don't think it's reasonable or fair to
> expect users to be doing this.

If you have a rank or requirements expression that can implement the 
policy you want, you can automatically add this to every submit by using the

SUBMIT_EXPRS config knob.

> I was thinking of doing something along the lines of logically
> dividing the nodes into n sub-pools (within which connectivity is good
> between all the nodes), and giving each sub-pool a number. This would
> then mean that an expression something like:
>
> NEGOTIATOR_PRE_JOB_RANK = (MY.Universe == PARALLEL) *
> ((free_nodes_in_my_subpool - MY.Machine_count) * my_subpool_id)
>
> Where sub-pool ID's were suitably large would achieve this. Obviously
> this isn't syntactically correct just yet!
>
> Actually in practice doing this is slightly harder than I'd hoped.
>
> Firstly is it true to say that (False * x) == 0? and (True * x) == x?
>
> Secondly how would I go about writing an expression that maps machine
> names into some (pre-defined) sub-pool Id's? Or am I better off
> putting that as a custom attribute in the startds ads?

I think the latter is an easier and cleaner approach.

> Thirdly is MachineCount an attribute in parallel universe job
> classads? I can't see it listed in
> http://www.cs.wisc.edu/condor/manual/v7.0/Appendix_A_ClassAd.html

MinHosts is what you want.
> Fourthly how could free_nodes_in_my_subpool be implemented?
>
> Or generally is there a nicer way to solve this without topological
> changes to the network or intervention from each user of the parallel
> universe?

There's also the ParallelSchedulingGroups feature which may help.

http://www.cs.wisc.edu/condor/manual/v7.1/3_12Setting_Up.html#SECTION004128400000000000000

-Greg

> Thanks,
> Alan
> _______________________________________________
> Condor-users mailing list
> To unsubscribe, send a message to condor-users-request@xxxxxxxxxxx with a
> subject: Unsubscribe
> You can also unsubscribe by visiting
> https://lists.cs.wisc.edu/mailman/listinfo/condor-users
>
> The archives can be found at: 
> https://lists.cs.wisc.edu/archive/condor-users/