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Subject: Re: [OMPI users] How does authentication between nodes work without password? (Newbie alert on)
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-02-14 09:16:58

On Feb 13, 2011, at 2:37 PM, Tena Sakai wrote:

> Also, here is an idea I came up in my sleep that I want to check
> out. The ami I have been using is a centos 5.5, which I have built
> from ground up. EC2 has something called Amazon Linux ami. I
> don't know what distribution that is and I am sure it doesn't have
> R, nor openmpi. But I thought I would load these components I
> need to the Amazon Linux (again as you suggest by starting the
> simplest case) and see if I can reproduce the behavior I have
> been experiencing on different (and Amazon "official" ami).

This is most telling to me (that you have a custom-built Linux). Now that I'm back at a proper keyboard, I checked why pipe(2) would fail, and it only has 3 reasons in both Linux and OS X:

- pointer is invalid (which is not the case here)
- process' file descriptor table is full
- kernel's file descriptor table is full

It would be quite surprising to run into either of the last 2 cases in a stock Linux kernel build.

One further thought -- ensure that SELinux is disabled (all the extra security stuff). I'm guessing that Open MPI *can* run with SELinux if SELinux is configured in a specific way, but I have no direct experience with that.

Jeff Squyres
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