title: How to create Kafka-python producer with ssl configuration
body: <p>I'm trying to create kafka producer with ssl. I need information on how to set SSL parameters in the constructor, the information provided in kafka-python client is not descriptive enough. </p>
  
  <p>What are the <code>ssl_certfile</code>, <code>ssl_cafile</code>, <code>ssl_keyfile</code> parameters. I'm not sure where to look for these files.</p>
  
  <pre><code>producer = KafkaProducer(bootstrap_servers=kafka_broker,
    value_serializer=lambda v: json.dumps(v).encode('utf-8'),
    security_protocol='SSL',
    api_version=(0,10),
    ssl_cafile='ca-certs.pem',ssl_certfile='server.pem',
    ssl_keyfile='server.pem',ssl_password='xxx')
  producer.send('rk976772_topic',{"test":0})
  </code></pre>
  
  <blockquote>
    <p>Traceback (most recent call last):   File "", line 1, in
       File
    "/usr/lib/python2.7/site-packages/kafka/producer/kafka.py", line 543,
    in send
        self._wait_on_metadata(topic, self.config['max_block_ms'] / 1000.0)   File "/usr/lib/python2.7/site-packages/kafka/producer/kafka.py", line 664,
    in _wait_on_metadata
        "Failed to update metadata after %.1f secs." % max_wait) kafka.errors.KafkaTimeoutError: KafkaTimeoutError: Failed to update
    metadata after 60.0 secs.</p>
  </blockquote>