[bgl-discuss] Re: Fw: question about opening sockets from compute nodes (fwd)

[Rob Ross <rross@xxxxxxxxxxx>]

FYI, discussion with IBM person about running things on IOnodes and 
connecting to them.

I have successfully created a TCP socket from a compute node and connected 
to a process on the login node (the sshd in this case).  I'm currently 
working on hacking netpipe to allow me to test the bandwidth of this 
connection, which Pete has named the "colon hack" because of the format of 
the fake filename.  This is how it works:

---

#include <fcntl.h>

int main(int argc, char **argv)
{
        int i;

        i = open("tcp://172.30.1.101:22", O_RDWR);
        printf("open returned %d\n", i);
        if (i < 0) {
                perror("open");
        }

        if (i >= 0) sleep(10);

        return 0;
}

---

<Feb  8 14:54:11> MPIRUN (Info) : Job started successfully
<Feb  8 14:54:11> MPIRUN (Info) : Waiting for job to terminate...
0: open returned 3
<Feb  8 14:54:41> MPIRUN (Info) : Job 1246 switched to state 
RM_JOB_TERMINATED ('T')
<Feb  8 14:54:41> MPIRUN (Info) : Job successfully terminated

---

/home/rross> netstat -tan | grep ":22" | grep "172.30.1.101"
tcp        0      0 172.30.1.101:22         172.30.1.100:1022 ESTABLISHED 
tcp        0      0 172.30.1.101:22         172.30.1.20:32768 ESTABLISHED 
/home/rross>

---

I'll report back more when I have the netpipe working...

Rob

---------- Forwarded message ----------
Date: Tue, 8 Feb 2005 17:47:50 -0500
From: Christopher Howson <chowson@xxxxxxxxxx>
To: Rob Ross <rross@xxxxxxxxxxx>
Subject: Re: Fw: question about opening sockets from compute nodes

Hi,

Do you have anything with powerpc-bgl-linux-gnu?
Otherwise, I must confess that I don't know what the deployed toolchains 
look like.

If you are feeling adventurous you might be OK with a standard 
powerpc-linux-gnu compiler, as the
user level ISA should be compatible (but don't do floating point).

Regards,
C. Howson.
To:     Christopher Howson/Watson/IBM@IBMUS
cc: 
Subject:        Re: Fw: question about opening sockets from compute nodes



Chris,

What's the right toolchain to use to build binaries that will run on an
IOnode?

Thanks,

Rob

On Tue, 8 Feb 2005, Christopher Howson wrote:

> Hi Rob,
>
> Yes.
> If you start the daemon on the IO node at boot, any program on the 
compute
> node should be able to connect to
> it as a client connection to 127.0.0.1.
> One difficulty would be telling the daemon about job starts and stops so
> it can clean up any state it has.
> But that can probably wait for a while (eg. for the time being do it as
> part of the initial setup can be to clean out the previous state).
>
> Regards,
> C. Howson.
>
>
> To:     Christopher Howson/Watson/IBM@IBMUS
> cc:     Hao Yu/Watson/IBM@IBMUS
> Subject:        Re: Fw: question about opening sockets from compute 
nodes
>
>
>
> Hi Chris,
>
> I can probably do that; we've been discussing that sort of thing here.
> We've just started to figure out out the boot sequence on the IOnodes
> works.
>
> I guess I would need to use this same open() trick to communicate with a
> daemon on the IOnode?
>
> Thanks,
>
> Rob
>
> On Tue, 8 Feb 2005, Christopher Howson wrote:
>
> > Can modify your /bgl/dist/etc/rc.local file to start your daemon on
> system
> > boot?
> >
> > Regards,
> > C. Howson.
> >
> > PS. They have changed the startup files that get called, but I think
> that
> > rc.local or rc.sysinit should be available somewhere
> > on the system under /bgl. That is how ciod is started.
> >
> > To:     Hao Yu/Watson/IBM@IBMUS
> > cc:     Christopher Howson/Watson/IBM@IBMUS
> > Subject:        Re: Fw: question about opening sockets from compute
> nodes
> >
> >
> >
> > Yes, that's exactly what I'm working on.  I would very much like to be
> > able to run some sort of user-space helper daemon on the IO node.
> >
> > What options are available there?
> >
> > Thanks!
> >
> > Rob
>
>
>


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