title: ZeroMQ fails to .bind() on Docker on [0.0.0.0:5555] - address already in use. Why?
body: <p>Got a bit problem with ZeroMQ socket on trying to <strong><code>.bind()</code></strong> on <code>0.0.0.0:5555</code> address, when tried to run it in Docker container via a Rancher Cattle.</p>
  
  <p>Every time I try to run it, I'm getting the same error:</p>
  
  <blockquote>
    <p>zmq.error.ZMQError: Address already in use.</p>
  </blockquote>
  
  <p>Tried to do <code>EXPOSE 5555</code> and <code>EXPOSE 5555/tcp</code> in my Dockerfile, but it did not help me.</p>
  
  <p>Here is a part of my code:</p>
  
  <pre><code>...
  self.context = zmq.Context()
  self.socket = self.context.socket(zmq.PUB)
  self.socket.bind('tcp://%s:%d' % ('0.0.0.0', 5555))
  ...
  </code></pre>
  
  <p>Maybe somebody had the same problem. How to solve it?</p>