title: IPython parallel computing not working
body: <p>I am trying to get ipython parallel programming working on a Linux machine (Rocks/CentOS 5.4, Python 2.7.2, IPython 0.11). The installation had no problems, however, I am unable to execute any command using <code>ipcluster</code>/<code>ipython</code>.</p>
  
  <p>Namely, I tried the following commands. On the <code>ipcluster</code> side:</p>
  
  <pre><code>/share/apps/Python-2.7/bin/ipcluster start --n=4
  </code></pre>
  
  <p>On the <code>ipython</code> side:</p>
  
  <pre><code>[malkarouri@grid02 ~]$ /share/apps/Python-2.7/bin/ipython
  Python 2.7.2 (default, Oct 18 2011, 15:35:37) 
  Type "copyright", "credits" or "license" for more information.
  
  IPython 0.11 -- An enhanced Interactive Python.
  ?         -&gt; Introduction and overview of IPython's features.
  %quickref -&gt; Quick reference.
  help      -&gt; Python's own help system.
  object?   -&gt; Details about 'object', use 'object??' for extra details.
  
  In [1]: from IPython.parallel import Client
  
  In [2]: rc=Client()
  
  In [3]: dview=rc[:]
  
  In [4]: ar=dview.apply_async(lambda x: x + 3, 7)
  
  In [5]: ar.get()
  </code></pre>
  
  <p>after which the last command never comes back with an answer (effectively hangs).</p>
  
  <p>How can I get <code>ipython</code> parallel processing to work?</p>