possible problem:
- wrong port, if you use a Java or Scala client, correct port is
9300, not9200 - wrong cluster name, make sure the cluster name you set in your code is the same as the cluster.name you set in
$ES_HOME/config/elasticsearch.yml - the sniff option, set
client.transport.sniffto betruebut can’t connect to all nodes of ES cluster will cause this problem too. ES doc here explained why.