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Subject: Re: [OMPI users] How does authentication between nodes work without password? (Newbie alert on)
From: Tena Sakai (tsakai_at_[hidden])
Date: 2011-02-14 18:34:39


Hi Jeff,

Many thanks for your reply / post.

> This is most telling to me (that you have a custom-built Linux)
I want to be clear that what I have is custom-built ami (Amazon
machine image), which is based on (run of the mill) centos 5.5.

> - 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.

Point well taken. I will re-verify that I don't have a permission
problem.

> 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.

I just checked and my ami does not have /etc/selinux/config file. I will
update the ami, relaunch and will report back.

Regards,

Tena

On 2/14/11 6:16 AM, "Jeff Squyres" <jsquyres_at_[hidden]> wrote:

> 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.