title: NoHostAvailable exception connecting to Cassandra from python
body: <p>I am obtaining an exception when trying to connect to my local instance of Cassandra from Python. I can connect to Cassandra with no problems using cqlsh. The version I am running is Cassandra 3.01 on ubuntu:</p>
  
  <pre><code>cqlsh
  Connected to Test Cluster at 127.0.0.1:9042.
  [cqlsh 5.0.1 | Cassandra 3.0.1 | CQL spec 3.3.1 | Native protocol v4]
  </code></pre>
  
  <p>The exception I obtain is below:</p>
  
  <pre><code>ERROR:cassandra.cluster:Control connection failed to connect, shutting down Cluster:
  Traceback (most recent call last):
    File "cassandra/cluster.py", line 840, in   cassandra.cluster.Cluster.connect (cassandra/cluster.c:11146)
    File "cassandra/cluster.py", line 2088, in cassandra.cluster.ControlConnection.connect (cassandra/cluster.c:36955)
    File "cassandra/cluster.py", line 2123, in cassandra.cluster.ControlConnection._reconnect_internal (cassandra/cluster.c:37811)
   NoHostAvailable: ('Unable to connect to any servers', {'127.0.0.1':       InvalidRequest(u'code=2200 [Invalid query] message="unconfigured table schema_keyspaces"',), 'localhost': InvalidRequest(u'code=2200 [Invalid query] message="unconfigured table schema_keyspaces"',)
  </code></pre>
  
  <p>I have checked my cassandra.yaml file and it looks ok:</p>
  
  <pre><code>egrep 'rpc_port:|native_transport_port:' /etc/cassandra/cassandra.yaml
  native_transport_port: 9042
  rpc_port: 9160
  </code></pre>
  
  <p>Anything else I can look at ? Suggestions are most welcome.</p>