After a successful fresh Installation of HDP 3.1.0 on a 2 node Ubuntu 18.0.4 instances, we were able to get all the services up and running. But after a night off, Datanode doesn't start. Following is the error: ERROR datanode.DataNode (DataNode.java:secureMain(2883)) - Exception in secureMain java.io.IOException: The path component: '/' in '/var/lib/hadoop-hdfs/dn_socket' has permissions 0777 uid 0 and gid 0. It is not protected because it is world-writable. This might help: 'chmod o-w /'. For more information: https://wiki.apache.org/hadoop/SocketPathSecurity     at org.apache.hadoop.net.unix.DomainSocket.validateSocketPathSecurity0(Native Method)     at org.apache.hadoop.net.unix.DomainSocket.bindAndListen(DomainSocket.java:193)     at org.apache.hadoop.hdfs.net.DomainPeerServer.<init>(DomainPeerServer.java:40)     at org.apache.hadoop.hdfs.server.datanode.DataNode.getDomainPeerServer(DataNode.java:1194)     at org.apache.hadoop.hdfs.server.datanode.DataNode.initDataXceiver(DataNode.java:1161)     at org.apache.hadoop.hdfs.server.datanode.DataNode.startDataNode(DataNode.java:1416)     at org.apache.hadoop.hdfs.server.datanode.DataNode.<init>(DataNode.java:500)     at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:2782)     at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:2690)     at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:2732)     at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:2876)     at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:2900) 2019-04-08 17:36:52,452 INFO  util.ExitUtil (ExitUtil.java:terminate(210)) - Exiting with status 1: java.io.IOException: The path component: '/' in '/var/lib/hadoop-hdfs/dn_socket' has permissions 0777 uid 0 and gid 0. It is not protected because it is world-writable. This might help: 'chmod o-w /'. For more information: https://wiki.apache.org/hadoop/SocketPathSecurity 2019-04-08 17:36:52,456 INFO  datanode.DataNode (LogAdapter.java:info(51)) - SHUTDOWN_MSG I did check the socket file and it's parent directories, I don't see the 777 permission at any level. But still the error appears while starting the datanode. Couldn't find any solution, so posted here for help. I have also uploaded the complete logs for the datanode. hadoop-hdfs-datanode.txtRegards, Vinay MP ... View more

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