Sorry If I misunderstood but, Should the mpirun -np4 hostname command return all the machines no the openmpi-default-hostfile?<br><br>My host file has just two ips, the first is the server and the second a node.<br><br>192.168.0.1 <br>

192.168.0.3 <br><br>It just return the name of my server 4 times.<br><br>The same happens with other commands like &quot;ls&quot; or just &quot;dir&quot;.<br><br>I didn&#39;t understood yet why does the mpi run the process 4 times or x times. It must be just one but spreading it on the other machines. Must not it??<br>

<br><br><br><br><br><div class="gmail_quote">On Tue, Jan 5, 2010 at 6:14 PM, Jeff Squyres <span dir="ltr">&lt;<a href="mailto:jsquyres@cisco.com">jsquyres@cisco.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">

You might want to try something simpler than java to start with.  For example:<br>
<br>
mpirun -np 4 hostname<br>
<br>
(where hostname is the POSIX command line app, not an MPI app)<br>
<br>
You should see the hostnames from the first 4 hosts in your hostfile (assuming each one of them has 1 process slot).  Then try running the samples that are in the examples/ directory in the Open MPI tarball (make sure that the example executables are available in the same location on every node).  For example:<br>


<br>
cd examples<br>
make<br>
mpirun -np 4 hello_c<br>
<br>
That&#39;s a trivial C MPI application that is the MPI equivalent of &quot;hello world&quot;.<br>
<br>
<br>
On Jan 5, 2010, at 11:18 AM, Leonardo Machado Moreira wrote:<br>
<br>
&gt; Hi, I have created a cluster with openmpi this way.<br>
&gt;<br>
&gt; 1 - Configured SSH with authorized_keys from the server to the nodes.<br>
&gt; 2 - In /etc/openmpi-default-hostfile\ I have typed the IP of every nodes and the server.<br>
&gt; 3 - Afterward I have created a Java application of two threads just to type a text on the console and runned it by<br>
&gt; mpirun -1 java javaprogram<br>
&gt; or<br>
&gt; mpirun -2 java javaprogram<br>
&gt; It is on the ps -aux of the server but the nodes are still stoped.<br>
&gt;<br>
&gt; How can I know that my mpi is working<br>
&gt;<br>
&gt; Thanks a lot<br>
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<br>
<br>
--<br>
Jeff Squyres<br>
<a href="mailto:jsquyres@cisco.com">jsquyres@cisco.com</a><br>
<br>
<br>
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</blockquote></div><br>