Reuti wrote:
Hi,

Am 20.10.2006 um 01:08 schrieb Orion Poplawski:

I'm starting to test out OpenMPI 1.2 tight integration with SGE and have run into the following issue. Currently, my startmpi script massages the hostnames in the machines file created from the SGE pe_hostfile add an "x" suffix on machines that are connected with a separate GigE network dedicated for MPI traffic.

With tight integration, openmpi uses the SGE pe_hostfile directly, e.g.:

coop00.cora.nwra.com 2 coo...@coop00.cora.nwra.com <NULL>
coop01.cora.nwra.com 2 coo...@coop01.cora.nwra.com <NULL>

Now, how/can I modify this so that MPI traffic speaks to coop00x and coop01x? One immediate problem that I'm running into is that the startmpi script from the SGE PE runs as the user of the job so it can't modify pe_hostfile.

is the name of the pe_hostfile hardcoded, to point to the one in the nodes spool directory, or is OpenMPI using the $PE_HOSTFILE, which you could reset to a new name to point to a modified one? Another issue might be the back-channel of the communication, where sometimes simply the `hostname` of the sender is taken to answer.

(Sending this to the openmpi-devel list as well I see what insight they may have. This seems like a common use case.)

It uses $PE_HOSTFILE, so I made a startup script that created a new pe_hostfile. This requires something like the following in my job script:

setenv PE_HOSTFILE $TMPDIR/pe_hostfile
orterun -np $NSLOTS $*

which is unfortunate that it can't be handled automatically somehow.

First tried:

coop01x.cora.nwra.com 2 coo...@coop01.cora.nwra.com <NULL>
coop00x.cora.nwra.com 2 coo...@coop00.cora.nwra.com <NULL>

Which yielded:

error: commlib error: access denied (client IP resolved to host name "coop01x.cora.nwra.com". This is not identical to clients host name "coop01.cora.nwra.com") error: executing task of job 41354 failed: failed sending task to ex...@coop00x.cora.nwra.com: can't find connection [coop01:27468] ERROR: A daemon on node coop00x.cora.nwra.com failed to start as expected.
[coop01:27468] ERROR: There may be more information available from
[coop01:27468] ERROR: the 'qstat -t' command on the Grid Engine tasks.
[coop01:27468] ERROR: If the problem persists, please restart the
[coop01:27468] ERROR: Grid Engine PE job
[coop01:27468] ERROR: The daemon exited unexpectedly with status 1.
error: commlib error: access denied (client IP resolved to host name "coop01x.cora.nwra.com". This is not identical to clients host name "coop01.cora.nwra.com") error: executing task of job 41354 failed: failed sending task to ex...@coop01x.cora.nwra.com: can't find connection

Then:

coop01x.cora.nwra.com 2 coo...@coop01x.cora.nwra.com <NULL>
coop00x.cora.nwra.com 2 coo...@coop00x.cora.nwra.com <NULL>

which yields:

error: commlib error: access denied (client IP resolved to host name "coop01x.cora.nwra.com". This is not identical to clients host name "coop01.cora.nwra.com") error: executing task of job 41356 failed: failed sending task to ex...@coop01x.cora.nwra.com: can't find connection error: commlib error: access denied (client IP resolved to host name "coop01x.cora.nwra.com". This is not identical to clients host name "coop01.cora.nwra.com") [coop01:27945] ERROR: A daemon on node coop01x.cora.nwra.com failed to start as expected.
[coop01:27945] ERROR: There may be more information available from
[coop01:27945] ERROR: the 'qstat -t' command on the Grid Engine tasks.
[coop01:27945] ERROR: If the problem persists, please restart the
[coop01:27945] ERROR: Grid Engine PE job
[coop01:27945] ERROR: The daemon exited unexpectedly with status 1.
error: executing task of job 41356 failed: failed sending task to ex...@coop00x.cora.nwra.com: can't find connection


Now, looking at the OpenMPI gridengine code, it looks like it gets the node name from the first entry in the pe_hostfile, and never really uses the queue name for anything.

        ptr = strtok_r(buf, " \n", &tok);
        num = strtok_r(NULL, " \n", &tok);
        queue = strtok_r(NULL, " \n", &tok);
        arch = strtok_r(NULL, " \n", &tok);
...
        node->node_name = strdup(ptr);
        node->node_arch = strdup(arch);

Perhaps it can be modified it uses the queue name hostname when doing SGE/qrsh calls, but the first hostname when doing MPI communication. Not really sure what the intent of the two fields in SGE's pe_hostfile is, or if OpenMPI can handle the idea of two hostnames for different purposes.

--
Orion Poplawski
System Administrator                  303-415-9701 x222
NWRA/CoRA Division                    FAX: 303-415-9702
3380 Mitchell Lane                  or...@cora.nwra.com
Boulder, CO 80301              http://www.cora.nwra.com

Reply via email to