https://community.cloudera.com/t5/Support-Questions/The-DataNode-is-not-connected-to-one-or-more-of-its-NameNode/m-p/45184#M46131 <P>Hi, i'm new to cloudera. i managed to install CDH &nbsp;5 on my ubuntu machine. Now i'm trying to run the sample&nbsp;MapReduce program given in HUE. But i'm facing some problems. When i access the Namenode UI, i'm able to see the following.</P><P>&nbsp;</P><P>&nbsp;</P><PRE>Safe mode is ON. The reported blocks 0 needs additional 804 blocks to reach the threshold 0.9990 of total blocks 804. The number of live datanodes 0 has reached the minimum number 0. Safe mode will be turned off automatically once the thresholds have been reached.</PRE><P>&nbsp;</P><P>And my datanode is completely down. i'm getting the following error in logs.</P><P>&nbsp;</P><PRE>ERROR org.apache.hadoop.hdfs.server.datanode.DataNode Initialization failed for Block pool BP-188106977-192.168.1.83-1467389018936 (Datanode Uuid bb6abb9f-79f6-47ce-bb2d-af7ff290b32f) service to humworld-Inc/127.0.1.1:8022 Datanode denied communication with namenode because the host is not in the include-list: DatanodeRegistration(127.0.0.1, datanodeUuid=bb6abb9f-79f6-47ce-bb2d-af7ff290b32f, infoPort=50075, infoSecurePort=0, ipcPort=50020, storageInfo=lv=-56;cid=cluster117;nsid=988195820;c=0) at org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager.registerDatanode(DatanodeManager.java:943) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.registerDatanode(FSNamesystem.java:5079) at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.registerDatanode(NameNodeRpcServer.java:1156) at org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolServerSideTranslatorPB.registerDatanode(DatanodeProtocolServerSideTranslatorPB.java:96) at org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos$DatanodeProtocolService$2.callBlockingMethod(DatanodeProtocolProtos.java:29184) at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:617) at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1073) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2086) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2082) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1693) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2080) Sep 16, 8:01:26.387 PM INFO org.apache.hadoop.hdfs.server.datanode.DataNode Block pool BP-188106977-192.168.1.83-1467389018936 (Datanode Uuid bb6abb9f-79f6-47ce-bb2d-af7ff290b32f) service to humworld-Inc/127.0.1.1:8022 beginning handshake with NN</PRE><P>Please help me with this.</P><P>&nbsp;</P><P>Thanks,</P><P>Karthi</P> Fri, 16 Sep 2022 10:39:40 GMT karthi8 2022-09-16T10:39:40Z