[Beowulf] first cluster

Fri Jul 16 10:11:29 PDT 2010

On Fri, Jul 16, 2010 at 12:51:49PM -0400, Steve Crusan wrote:
> We use a PAM module (pam_torque) to stop this behavior. Basically, if you
> your job isn't currently running on a node, you cannot SSH into a node.
> 
> 
> http://www.rpmfind.net/linux/rpm2html/search.php?query=torque-pam
> 
> That way one is required to use the queuing system for jobs, so the cluster
> isn't like the wild wild west...

Ah Ha!.  The key.

Thanks,
Douglas.

> On 7/16/10 10:59 AM, "Douglas Guptill" <douglas.guptill at dal.ca> wrote:
> 
> > On Fri, Jul 16, 2010 at 10:02:53AM +0100, Hearns, John wrote:
> > 
> >> As an aside, my two pence worth on this thread.
> > 
> > I agree, the topic seems to have shifted...
> > 
> >> To the original poster - you have done your research on what is needed
> >> for a first cluster.
> >> Take may advice, and that of a lot of people on this list, and contact a
> >> cluster vendor in your area.
> >> You will be surprised at how competitive the price is versus sourcing
> >> the parts yourself.
> >> And remember - people who build clusters are specialists in that task,
> >> you are a specialist in oceanography.
> > 
> > We have ordered the cluster from a local builder, and expect delivery
> > in about 4 weeks.  I am a servant of the Oceanographers, my specialty
> > is software.
> > 
> > Thanks for the advice.  I conclude there are no magic bullet
> > solutions.  One must do research, make an educated guess, and then
> > hold one's nose and jump in at the deep end.
> > 
> > There is one question that perplexes me, to which I have not found an
> > answer.
> > 
> > How does the presence of a job scheduler interact with the ability of a user
> > to
> >   ssh to <head>, 
> >   ssh to <compute-node-n>, and then type
> >   mpirun -np 64 my_application
> > 
> > Intuition tells me there has to be something in a cluster setup, when
> > it has a scheduler, that prevents a user from circumventing the
> > scheduler by doing something like the above.
> > 
> > Any hints?
> > 
> >> John Hearns McLaren Racing
> > 
> > BTW, congratulations on a great season this year.
> > 
> > Regards,
> > Douglas.
> 
> 
> 
> ----------------------
> Steve Crusan
> System Administrator
> Center for Research Computing
> University of Rochester
> https://www.crc.rochester.edu/
> 
> 

-- 
  Douglas Guptill                       voice: 902-461-9749
  Research Assistant, LSC 4640          email: douglas.guptill at dal.ca
  Oceanography Department               fax:   902-494-3877
  Dalhousie University
  Halifax, NS, B3H 4J1, Canada