我正在尝试为confluent platform运行cassandra sink connector。cassandra-sink.json文件如下所示：

{
      "name" : "cassandra-sink",
      "config" : {
        "connector.class" : "io.confluent.connect.cassandra.CassandraSinkConnector",
        "tasks.max" : "1",
        "topics" : "topic1",
        "cassandra.contact.points" : "127.0.0.1",
        "cassandra.keyspace" : "test",
        "confluent.topic.bootstrap.servers": "127.0.0.1:9092",
        "cassandra.write.mode" : "Update",
        "connect.cassandra.port":"127.0.0.1:9042"

      }
    }

我下载了 confluent-hub install confluentinc/kafka-connect-cassandra:latest 根据链接。
我可以加载文件，但当我检查状态，我得到以下错误。我搞不清楚问题出在哪里。

FAILED worker_id:127.0.0.1:8083,trace:com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) tried for query failed 
com.datastax.driver.core.exceptions.TransportException: [/127.0.0.1:9042] Cannot connect
com.datastax.driver.core.ControlConnection.reconnectInternal
com.datastax.driver.core.ControlConnection.connect
com.datastax.driver.core.Cluster$Manager.negotiateProtocolVersionAndConnect
com.datastax.driver.core.Cluster$Manager.init
com.datastax.driver.core.Cluster.init
com.datastax.driver.core.SessionManager.initAsync
com.datastax.driver.core.SessionManager.executeAsync
com.datastax.driver.core.AbstractSession.execute
io.confluent.connect.cassandra.CassandraSessionImpl.executeStatement
io.confluent.connect.cassandra.CassandraSinkConnector.doStart
io.confluent.connect.cassandra.CassandraSinkConnector.start
org.apache.kafka.connect.runtime.WorkerConnector.doStart
org.apache.kafka.connect.runtime.WorkerConnector.start
org.apache.kafka.connect.runtime.WorkerConnector.transitionTo 
org.apache.kafka.connect.runtime.Worker.startConnector
org.apache.kafka.connect.runtime.distributed.DistributedHerder.startConnector 
org.apache.kafka.connect.runtime.distributed.DistributedHerder.access$1300
org.apache.kafka.connect.runtime.distributed.DistributedHerder$14
org.apache.kafka.connect.runtime.distributed.DistributedHerder$14 
java.util.concurrent.FutureTask.run java.util.concurrent.ThreadPoolExecutor.runWorker
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) 
             java.lang.Thread.run

请引导。