Hadoop Config in Docker - Datanode won't connect

Question

I am trying to build a dockerized hadoop system. I am currently having the issue that the datanode's will not connect to the namenode. For some background: each docker image is running both its hadoop role and a free-ipa client and all are using free ipa for dns. All hdfs services are being run under the hdfs user uid: 6001 gid: 6001 group: hadoop.

This is the error I am seeing on the namenode:

2014-10-16 15:52:28,066 WARN  [IPC Server handler 4 on 8020] blockmanagement.DatanodeManager (DatanodeManager.java:registerDatanode(738)) - Unresolved datanode registration from 172.31.1.166
2014-10-16 15:52:28,067 ERROR [IPC Server handler 4 on 8020] security.UserGroupInformation (UserGroupInformation.java:doAs(1494)) - PriviledgedActionException as:hdfs (auth:SIMPLE) cause:org.apache.hadoop.hdfs.server.protocol.DisallowedDatanodeException: Datanode denied communication with namenode: DatanodeRegistration(0.0.0.0, storageID=DS-300514933-172.31.1.166-50010-1413489147639, infoPort=50075, ipcPort=50020, storageInfo=lv=-47;cid=CID-41426277-e1f8-4154-8189-a0b556231333;nsid=900398376;c=0)
2014-10-16 15:52:28,068 INFO  [IPC Server handler 4 on 8020] ipc.Server (Server.java:run(2075)) - IPC Server handler 4 on 8020, call org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol.registerDatanode from 172.31.1.166:35452 Call#1 Retry#0: error: org.apache.hadoop.hdfs.server.protocol.DisallowedDatanodeException: Datanode denied communication with namenode: DatanodeRegistration(0.0.0.0, storageID=DS-300514933-172.31.1.166-50010-1413489147639, infoPort=50075, ipcPort=50020, storageInfo=lv=-47;cid=CID-41426277-e1f8-4154-8189-a0b556231333;nsid=900398376;c=0)
org.apache.hadoop.hdfs.server.protocol.DisallowedDatanodeException: Datanode denied communication with namenode: DatanodeRegistration(0.0.0.0, storageID=DS-300514933-172.31.1.166-50010-1413489147639, infoPort=50075, ipcPort=50020, storageInfo=lv=-47;cid=CID-41426277-e1f8-4154-8189-a0b556231333;nsid=900398376;c=0)
at org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager.registerDatanode(DatanodeManager.java:739)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.registerDatanode(FSNamesystem.java:3944)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.registerDatanode(NameNodeRpcServer.java:948)
at org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolServerSideTranslatorPB.registerDatanode(DatanodeProtocolServerSideTranslatorPB.java:90)
at org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos$DatanodeProtocolService$2.callBlockingMethod(DatanodeProtocolProtos.java:24079)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:928)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2053)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2047)

and on the datanode:

2014-10-16 15:52:28,030 INFO  [DataNode: [file:/data/hdfs/dd]  heartbeating to namenode.example.internal/172.31.1.51:8020] datanode.DataNode (BPServiceActor.java:register(618)) - Block pool BP-763144819-172.31.1.51-1413403838191 (storage id DS-300514933-172.31.1.166-50010-1413489147639) service to namenode.example.internal/172.31.1.51:8020 beginning handshake with NN
2014-10-16 15:52:28,083 FATAL [DataNode: [file:/data/hdfs/dd]  heartbeating to namenode.example.internal/172.31.1.51:8020] datanode.DataNode (BPServiceActor.java:run(668)) - Initialization failed for block pool Block pool BP-763144819-172.31.1.51-1413403838191 (storage id DS-300514933-172.31.1.166-50010-1413489147639) service to namenode.example.internal/172.31.1.51:8020
org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.protocol.DisallowedDatanodeException): Datanode denied communication with namenode: DatanodeRegistration(0.0.0.0, storageID=DS-300514933-172.31.1.166-50010-1413489147639, infoPort=50075, ipcPort=50020, storageInfo=lv=-47;cid=CID-41426277-e1f8-4154-8189-a0b556231333;nsid=900398376;c=0)
at org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager.registerDatanode(DatanodeManager.java:739)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.registerDatanode(FSNamesystem.java:3944)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.registerDatanode(NameNodeRpcServer.java:948)
at org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolServerSideTranslatorPB.registerDatanode(DatanodeProtocolServerSideTranslatorPB.java:90)
at org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos$DatanodeProtocolService$2.callBlockingMethod(DatanodeProtocolProtos.java:24079)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:928)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2053)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2047)

at org.apache.hadoop.ipc.Client.call(Client.java:1347)
at org.apache.hadoop.ipc.Client.call(Client.java:1300)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206)
at com.sun.proxy.$Proxy9.registerDatanode(Unknown Source)
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.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:186)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
at com.sun.proxy.$Proxy9.registerDatanode(Unknown Source)
at org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolClientSideTranslatorPB.registerDatanode(DatanodeProtocolClientSideTranslatorPB.java:146)
at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.register(BPServiceActor.java:623)
at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:225)
at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:664)
at java.lang.Thread.run(Thread.java:744)

Answer 1

I figured it out!

It is important for hadoop to have both forward and reverse dns and I was failing to create the reverse dns records.

Make Sure To Do That!!!!