hadoop datanode 启动正常，但master无法识别（50030不显示datanode节点）

start-all.sh 启动

坑爹

找不出错

试了各种办法，重新formaet 查看 集群ID是否相同。都无效

日志也没看到错

按官网方法手动一步步启，问题照旧

master节点，yarn namenode 启动（打印详细日志）

node节点 yarn datanode 启动

看到错了

15/07/02 03:32:51 INFO datanode.DataNode: Block pool BP-89742471-127.0.1.1-1435821846469 (Datanode Uuid null) service to /172.16.231.176:8020 beginning handshake with NN

15/07/02 03:32:52 ERROR datanode.DataNode: Initialization failed for Block pool BP-89742471-127.0.1.1-1435821846469 (Datanode Uuid null) service to /172.16.231.176:8020 Datanode denied communication with namenode because hostname cannot be resolved (ip=172.16.231.175, hostname=172.16.231.175): DatanodeRegistration(0.0.0.0:50010, datanodeUuid=c165abfd-1c06-4259-8588-c805abd72fca, infoPort=50075, infoSecurePort=0, ipcPort=50020, storageInfo=lv=-56;cid=CID-c13bccb4-70ca-43f7-94f7-1b66bbaf64dd;nsid=1827594974;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:4485)

at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.registerDatanode(NameNodeRpcServer.java:1271)

at org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolServerSideTranslatorPB.registerDatanode(DatanodeProtocolServerSideTranslatorPB.java:95)

at org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos$DatanodeProtocolService$2.callBlockingMethod(DatanodeProtocolProtos.java:28539)

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)

问题在这里hostname cannot be resolved (ip=172.16.231.175, hostname=172.16.231.175)

改slaves 文件 中的ip 为hostname

如

datanode1

datanode2

配置/etc/hosts

172.16.231.173 datanode1

172.16.231.174 datanode2

再启动，解决

问题是 slaves  不能写ip 只能写hostname