title: Celery upgrade (3.1->4.1) - Connection reset by peer
body: <p>We are working with celery at the last year, with ~15 workers, each one defined with concurrency between 1-4.</p>
  
  <p>Recently we upgraded our celery from v3.1 to v4.1</p>
  
  <p>Now we are having the following errors in each one of the workers logs, any ideas what can cause to such error?</p>
  
  <pre><code>2017-08-21 18:33:19,780 94794  ERROR   Control command error: error(104, 'Connection reset by peer') [file: pidbox.py, line: 46]
  Traceback (most recent call last):
    File "/srv/dy/venv/lib/python2.7/site-packages/celery/worker/pidbox.py", line 42, in on_message
      self.node.handle_message(body, message)
    File "/srv/dy/venv/lib/python2.7/site-packages/kombu/pidbox.py", line 129, in handle_message
      return self.dispatch(**body)
    File "/srv/dy/venv/lib/python2.7/site-packages/kombu/pidbox.py", line 112, in dispatch
      ticket=ticket)
    File "/srv/dy/venv/lib/python2.7/site-packages/kombu/pidbox.py", line 135, in reply
      serializer=self.mailbox.serializer)
    File "/srv/dy/venv/lib/python2.7/site-packages/kombu/pidbox.py", line 265, in _publish_reply
      **opts
    File "/srv/dy/venv/lib/python2.7/site-packages/kombu/messaging.py", line 181, in publish
      exchange_name, declare,
    File "/srv/dy/venv/lib/python2.7/site-packages/kombu/messaging.py", line 203, in _publish
      mandatory=mandatory, immediate=immediate,
    File "/srv/dy/venv/lib/python2.7/site-packages/amqp/channel.py", line 1748, in _basic_publish
      (0, exchange, routing_key, mandatory, immediate), msg
    File "/srv/dy/venv/lib/python2.7/site-packages/amqp/abstract_channel.py", line 64, in send_method
      conn.frame_writer(1, self.channel_id, sig, args, content)
    File "/srv/dy/venv/lib/python2.7/site-packages/amqp/method_framing.py", line 178, in write_frame
      write(view[:offset])
    File "/srv/dy/venv/lib/python2.7/site-packages/amqp/transport.py", line 272, in write
      self._write(s)
    File "/usr/lib64/python2.7/socket.py", line 224, in meth
      return getattr(self._sock,name)(*args)
  error: [Errno 104] Connection reset by peer
  </code></pre>
  
  <p>BTW: our tasks in the form:</p>
  
  <pre><code>@app.task(name='EXAMPLE_TASK'],
            bind=True,
            base=ConnectionHolderTask)
  def example_task(self, arg1, arg2, **kwargs):
      # task code
  </code></pre>