question java.lang.IllegalArgumentException: java.net.UnknownHostException: user in Support Questions

question java.lang.IllegalArgumentException: java.net.UnknownHostException: user in Support Questions https://community.cloudera.com/t5/Support-Questions/java-lang-IllegalArgumentException-java-net/m-p/12874#M22157 Hi there, I have installed hadoop cluster together with spark using cloudera free manager, i used all default values.Spark ios working, i can start spark-shell and on the web UI i see master and all the workers but everytime i try to run anything in spark-shell i get: java.lang.IllegalArgumentException: java.net.UnknownHostException: user at org.apache.hadoop.security.SecurityUtil.buildTokenService(SecurityUtil.java:377) at org.apache.hadoop.hdfs.NameNodeProxies.createNonHAProxy(NameNodeProxies.java:237) at org.apache.hadoop.hdfs.NameNodeProxies.createProxy(NameNodeProxies.java:141) at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:576) at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:521) at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:146) at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2397) at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:89) at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:2431) at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:2413) at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:368) at org.apache.hadoop.fs.Path.getFileSystem(Path.java:296) at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:221) at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:270) at org.apache.spark.rdd.HadoopRDD.getPartitions(HadoopRDD.scala:140) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:207) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:205) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:205) at org.apache.spark.rdd.MappedRDD.getPartitions(MappedRDD.scala:28) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:207) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:205) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:205) at org.apache.spark.rdd.FlatMappedRDD.getPartitions(FlatMappedRDD.scala:30) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:207) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:205) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:205) at org.apache.spark.rdd.MappedRDD.getPartitions(MappedRDD.scala:28) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:207) at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:205) at scala.Option.getOrElse(Option.scala:120) at org.apache.spark.rdd.RDD.partitions(RDD.scala:205) at org.apache.spark.Partitioner$.defaultPartitioner(Partitioner.scala:58) at org.apache.spark.rdd.PairRDDFunctions.reduceByKey(PairRDDFunctions.scala:355) at $iwC$$iwC$$iwC$$iwC.<init>(<console>:14) at $iwC$$iwC$$iwC.<init>(<console>:19) at $iwC$$iwC.<init>(<console>:21) at $iwC.<init>(<console>:23) at <init>(<console>:25) at .<init>(<console>:29) at .<clinit>(<console>) at .<init>(<console>:7) at .<clinit>(<console>) at $print(<console>) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:772) at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1040) at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:609) at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:640) at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:604) at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:795) at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:840) at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:752) at org.apache.spark.repl.SparkILoop.processLine$1(SparkILoop.scala:600) at org.apache.spark.repl.SparkILoop.innerLoop$1(SparkILoop.scala:607) at org.apache.spark.repl.SparkILoop.loop(SparkILoop.scala:610) at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply$mcZ$sp(SparkILoop.scala:935) at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:883) at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:883) at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135) at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:883) at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:981) at org.apache.spark.repl.Main$.main(Main.scala:31) at org.apache.spark.repl.Main.main(Main.scala) Caused by: java.net.UnknownHostException: user ... 69 more  Does anybody have a clue what is the issue here? i did find few posts that were taliking about localhost name and HADOOP_CONF_DIR defined on workers but nothing helped. Help is appreciated. regards,DaliborJ   Fri, 16 Sep 2022 08:59:30 GMT DaliborJ 2022-09-16T08:59:30Z