title: activate virtual environment using mpirun in interactive qsub environment
body: <p>I am using the openmdao 0.13 python module in a project. This module is only available as a virtualenv. When I activate the virtual env, it appears to only activate on one node. What could account for this strange behavior? Why are processors on non-primary nodes unable to load the virtualenv?</p>
  
  <pre><code>$ mpirun --version
  mpirun (Open MPI) 1.7.3
  $ qsub --version
  Version: 5.1.1.2
  $ qsub -V -I -l nodes=2:ppn=24
  $ cd openmdao-0.10.3.2/
  $ . bin/activate
  $ mpirun -np 24 python -c "import openmdao"
  # no errors
  $ mpirun -np 27 python -c "import openmdao"
  Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
  ImportError: No module named openmdao
  Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
  ImportError: No module named openmdao
  Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
  ImportError: No module named openmdao
  </code></pre>
  
  <p>It looks like all of my processors are referencing python correctly</p>
  
  <pre><code>$ mpirun -np 27 which python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  /home/jquick/here_it_is/openmdao-0.10.3.2/bin/python
  </code></pre>
  
  <p>I don't understand what could possibly be causing this import error. What could bin/activate be affecting on my primary but node but not on secondary nodes?</p>