title: how to fix python, urlopen error [Errno 8], using eventlet green
body: <p>Python novice here.</p>
  
  <p>I'm making a lot of asynchronous http requests using eventlet and urllib2. At the top of my file I have</p>
  
  <pre><code>import eventlet
  import urllib
  from eventlet.green import urllib2
  </code></pre>
  
  <p>Then I make a lot of asynchronous http requests that succeed with this line:</p>
  
  <pre><code>conn = urllib2.urlopen(signed_url, None)
  </code></pre>
  
  <p>And all of a sudden, I get this error:</p>
  
  <pre><code>URLError: &lt;urlopen error [Errno 8] nodename nor servname provided, or not known&gt;
  </code></pre>
  
  <p>This error occurs on the same urllib2.urlopen line, which is weird because it succeeded many times before. Also, when I print the signed_url and then just paste it to my browser, I get a proper response, so the url is properly formatted.</p>
  
  <p>I've bounced around posts, but cannot find the right debugging strategy for this. Conceptually, what can be causing this error? And how do you recommend I go about fixing it? </p>
  
  <p>I'm using Python 2.7.6.</p>
  
  <p>Thank you.</p>