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Subject: Re: [OMPI users] Accessing OpenMPI processes over Internet using ssh
From: Reuti (reuti_at_[hidden])
Date: 2011-11-24 04:00:53


Hi,

Am 24.11.2011 um 05:26 schrieb Jaison Paul:

> I am trying to access OpenMPI processes over Internet using ssh and not quite successful, yet. I believe that I should be able to do it.
>
> I have to run one process on my PC and the rest on a remote cluster over internet. I have set the public keys (at .ssh/authorized_keys) to access remote nodes without a password.
>
> I use hostfile to run mpi. It will read something like:
> -----------------------------
> localhost
> user_at_[hidden]

this is not a valid syntax for Open MPI.

> -----------------------------
> But it fails.
>
> The issue seems to be the user! That is, the user on my PC is different to that of user at remotehosts. That's my assumption.
>
> Is this the problem? Is there any work-around to solve this issue? Do I need to have same username at all nodes to solve this issue?

You can define nicknames for an ssh connection in a file ~/.ssh/config like:

Host foobar
    User baz
    Hostname the.remote.server.demo
    Port 1234

While this will work with any nickname for an ssh connection, in your case the nickname must match the one specified in the hostfile, as Open MPI won't use this lookup file:

Host remotehost.com
    User user

ssh should then use the entries therein to initiate the connection. For details you can have a look at `man ssh_config`.

-- Reuti