2020-05-09 19:05:28,223 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Block pool BP-1093355258-192.168.31.198-1589010135816 (Datanode Uuid null) service to hadoop198/192.168.31.198:9000 beginning handshake with NN
2020-05-09 19:05:28,228 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: Initialization failed for Block pool BP-1093355258-192.168.31.198-1589010135816 (Datanode Uuid null) service to hadoop198/192.168.31.198:9000 Datanode denied communication with namenode because hostname cannot be resolved (ip=192.168.31.195, hostname=192.168.31.195): DatanodeRegistration(0.0.0.0:50010, datanodeUuid=e562e511-d75b-471a-a3c6-734988654112, infoPort=50075, infoSecurePort=0, ipcPort=50020, storageInfo=lv=-56;cid=CID-cccf32b5-4ec3-458a-8c45-51f2493e0d00;nsid=2116542745;c=0)
        at org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager.registerDatanode(DatanodeManager.java:863)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.registerDatanode(FSNamesystem.java:4528)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.registerDatanode(NameNodeRpcServer.java:1285)
        at org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolServerSideTranslatorPB.registerDatanode(DatanodeProtocolServerSideTranslatorPB.java:96)
        at org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos$DatanodeProtocolService$2.callBlockingMethod(DatanodeProtocolProtos.java:28752)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)