CODEWITHSUNDEEP
hadoopmapreducehive
eigen
eigen

Reputation: 95

Mapreduce returns error when accessing to datanode on master machine

I set up a Hadoop 2.4.0 cluster with three machines. One master machine is deployed with namenode, resource manager, datanode and node manager. The other two worker machines are deployed with datanode and node manager. When I run Hive query, the work fails and the error is

2014-06-11 13:40:13,364 WARN [main] org.apache.hadoop.mapred.YarnChild: Exception running child : java.net.ConnectException: Call From master/127.0.0.1 to master:43607 failed on connection exception: java.net.ConnectException: Connection >refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:5>7) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImp>l.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:783) at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:730) at org.apache.hadoop.ipc.Client.call(Client.java:1414) at org.apache.hadoop.ipc.Client.call(Client.java:1363) at org.apache.hadoop.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:231) at com.sun.proxy.$Proxy9.getTask(Unknown Source) at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:136) Caused by: java.net.ConnectException: Connection refused at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739) at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206) at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:529) at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:493) at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:604) at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:699) at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:367) at org.apache.hadoop.ipc.Client.getConnection(Client.java:1462) at org.apache.hadoop.ipc.Client.call(Client.java:1381) ... 4 more

if I disable the datanode on master machine, everything works well. I'm wondering if it's allowed to deployed datanode on the master machine. Thank you for your kindly help in advance.

BTW, my /etc/hosts on the three machines are the same:

127.0.0.1 localhost

10.1.154.231 master

10.1.153.220 slave1

10.1.153.133 slave2

Upvotes: 0

Views: 376

Answers (2)

3cham
3cham

Reputation: 11

In this case you may check if the namenode is started correctly on the master by checking logs at your yourhadoopfolder/logs/hadoop-[hadoop-user]-namenode-master.log

It is often caused by the hdfs is not formatted before. Run

hadoop namenode -format

Of course you will need to put your data to the cluster again.

Upvotes: 0

WestCoastProjects
WestCoastProjects

Reputation: 63231

Please set up passwordless ssh on your master to itself.

You can achieve this by 

  cat ~/id_rsa.pub >> ~/.ssh/authorized_keys2

Make sure the permissions are correct

   chmod 0600 ~/.ssh/authorized_keys2

Upvotes: 1

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