The hostname/IP to connect to is specified in the listen_address
property of your cassandra.yaml.If you are connecting to Cassandra from your localhost only (a sandbox machine), then you can set the listen_address
in your cassandra.yaml accordingly:
listen_address: localhost
When you start Cassandra, you should see lines similar to this either in STDOUT or in your system.log (timestamps removed for brevity):
Starting listening for CQL clients on localhost/127.0.0.1:9042...
Binding thrift service to localhost/127.0.0.1:9160
Listening for thrift clients...
These lines indicate which address you should be using to connect to your cluster. The first way to test your connection, is with clqsh
. Note that cqlsh will connect to "localhost" by default. If you are connecting to a host/IP other than localhost, then you will need to specify it on the command line.
$ cqlsh
Connected to Test Cluster at localhost:9042.
[cqlsh 5.0.1 | Cassandra 2.1.0-rc5-SNAPSHOT | CQL spec 3.2.0 | Native protocol v3]
Use HELP for help.
cqlsh>
If this works, then you should also be able to connect (and test) from DataStax Dev Center (also on your local machine) by defining a connection to localhost, like this:

At this point, you should be able to connect via your application code (Java CQL3 driver shown):
cluster = Cluster.builder().addContactPoint("localhost").build();
Metadata metadata = cluster.Metadata;
Console.WriteLine("Connected to cluster: " + metadata.ClusterName.ToString());
Session session = cluster.connect();