Dear MPICH.

I have an additional information.

This "strange configuration" (hydra connected to computer not from the list) is result of unhandled Main process fail (similar to abort() call) without killing children process (hydra).

Thus I can see "init" process becomes a father of hydra process.

Can you please refer me to document explaining hydra behavior when father process is dead (an emergency situation).

I understand that this situation shouldn't happen and this bug will be fixed, but I'm curious about the hydra logic.

Regards,

Anatoly.

---------- Forwarded message ----------
From: Anatoly G <anatolyrishon@gmail.com>
Date: Wed, Dec 24, 2014 at 1:00 PM
Subject: mpiexec.hydra creates unexpectable TCP socket.
To: discuss@mpich.org

Dear MPICH.

I'm using mpich 3.1 (hydra+MPI).

I execute main application (Main) which calls mpiexec.hydra in following way:

mpiexec.hydra -genvall -disable-auto-cleanup -f MpiConfigMachines.txt -launcher=ssh -n 3 MPI_Prog

MpiConfigMachines.txt content:

10.3.2.100:1

10.3.2.101:2

Where 10.3.2.100 is a local host.

As result I get

Main + single MPI_Prog processes on local computer
2 MPI_Prog processes on remote one.

Main application establish TCP socket with local MPI_Prog.

Main application establish TCP socket with controller on other computer 10.3.2.170, which is not included in MpiConfigMachines.txt file.

After executing some time (hours, sometimes days) I see via netstat that created new connection from mpiexec.hydra and controller.

Before executing mpiexec.hydra I set environment variable

setenv MPIEXEC_PORT_RANGE 50010:65535

According to manual this variable limits hydra destination ports to [50010:65535].

I see that hydra uses these ports with MPI_Prog, but connection with controller done on port 701 (controller computer).

Controller program is a server. It can accept connections only.

Can you please advice how to stand with this problem?

How hydra recognizes controller IP and establish connection with it?

Sincerely,

Anatoly.