title: Failed to start devlopment server -- BindError: Unable to find a consistent port localhost
body: <p>Google-app-engine development server runs great yesterday, but when I try to start it today. It only shout out this Error. </p>
  
  <p>I tried use <code>lsof -i:8080</code> / <code>lsof -i:8000</code> to make sure these ports are not taken.
  I also tried use a --port arg to switch to another port. 
  I even removed the gae folder and installed a new one.
  -- with no luck at all.</p>
  
  <p>Maybe there is a obvious solution but I can't see it.</p>
  
  <p>Here is the Oh-My-God trace stack..</p>
  
  <pre><code>Traceback (most recent call last):
  File "/home/henry/software/google_appengine/dev_appserver.py", line 182, in &lt;module&gt;
          _run_file(__file__, globals())
  File "/home/henry/software/google_appengine/dev_appserver.py", line 178, in _run_file
          execfile(script_path, globals_)
  File "/home/henry/software/google_appengine/google/appengine/tools/devappserver2/devappserver2.py", line 689, in &lt;module&gt;
          main()
  File "/home/henry/software/google_appengine/google/appengine/tools/devappserver2/devappserver2.py", line 682, in main
          dev_server.start(options)
  File "/home/henry/software/google_appengine/google/appengine/tools/devappserver2/devappserver2.py", line 653, in start
          apis.start()
  File "/home/henry/software/google_appengine/google/appengine/tools/devappserver2/api_server.py", line 152, in start
          super(APIServer, self).start()
  File "/home/henry/software/google_appengine/google/appengine/tools/devappserver2/wsgi_server.py", line 294, in start
          raise BindError('Unable to find a consistent port %s' % host)
      google.appengine.tools.devappserver2.wsgi_server.BindError: Unable to find a consistent port localhost
      Exception in thread Thread-4 (most likely raised during interpreter shutdown):
      Traceback (most recent call last):
        File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
        File "/usr/lib/python2.7/threading.py", line 763, in runhenry@henry-A
  </code></pre>