org.elasticsearch.hadoop.EsHadoopIllegalArgumentException: Cannot detect ES version - typically this happens if the network/Elasticsearch cluster is not accessible or when targeting a WAN/Cloud instance without the proper setting 'es.nodes.wan.only'
  at org.elasticsearch.hadoop.rest.InitializationUtils.discoverAndValidateClusterInfo(InitializationUtils.java:335)
  at org.elasticsearch.hadoop.rest.RestService.findPartitions(RestService.java:220)
  at org.elasticsearch.spark.rdd.AbstractEsRDD.esPartitions$lzycompute(AbstractEsRDD.scala:79)
  at org.elasticsearch.spark.rdd.AbstractEsRDD.esPartitions(AbstractEsRDD.scala:78)
  at org.elasticsearch.spark.rdd.AbstractEsRDD.getPartitions(AbstractEsRDD.scala:48)
  at org.apache.spark.rdd.RDD.$anonfun$partitions$2(RDD.scala:300)
  at scala.Option.getOrElse(Option.scala:189)
  at org.apache.spark.rdd.RDD.partitions(RDD.scala:296)
  at org.apache.spark.SparkContext.runJob(SparkContext.scala:2261)
  at org.apache.spark.rdd.RDD.$anonfun$collect$1(RDD.scala:1030)
  at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
  at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
  at org.apache.spark.rdd.RDD.withScope(RDD.scala:414)
  at org.apache.spark.rdd.RDD.collect(RDD.scala:1029)
  ... 52 elided
Caused by: org.elasticsearch.hadoop.rest.EsHadoopNoNodesLeftException: Connection error (check network and/or proxy settings)- all nodes failed; tried [[127.0.0.1:9200]]
  at org.elasticsearch.hadoop.rest.NetworkClient.execute(NetworkClient.java:160)
  at org.elasticsearch.hadoop.rest.RestClient.execute(RestClient.java:441)
  at org.elasticsearch.hadoop.rest.RestClient.execute(RestClient.java:437)
  at org.elasticsearch.hadoop.rest.RestClient.execute(RestClient.java:405)
  at org.elasticsearch.hadoop.rest.RestClient.mainInfo(RestClient.java:754)
  at org.elasticsearch.hadoop.rest.InitializationUtils.discoverAndValidateClusterInfo(InitializationUtils.java:327)
  ... 65 more