HDFS error: could only be replicated to 0 nodes, i

Question

I've created a ubuntu single node hadoop cluster in EC2.

Testing a simple file upload to hdfs works from the EC2 machine, but doesn't work from a machine outside of EC2.

I can browse the the filesystem through the web interface from the remote machine, and it shows one datanode which is reported as in service. Have opened all tcp ports in the security from 0 to 60000(!) so I don't think it's that.

I get the error

java.io.IOException: File /user/ubuntu/pies could only be replicated to 0 nodes, instead of 1
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1448)
at org.apache.hadoop.hdfs.server.namenode.NameNode.addBlock(NameNode.java:690)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:342)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1350)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1346)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:742)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1344)

at org.apache.hadoop.ipc.Client.call(Client.java:905)
at org.apache.hadoop.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:198)
at $Proxy0.addBlock(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:82)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:59)
at $Proxy0.addBlock(Unknown Source)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.locateFollowingBlock(DFSOutputStream.java:928)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:811)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:427)

namenode log just gives the same error. Others don't seem to have anything interesting

Any ideas?

Cheers

Answer 1

If all data nodes are running, one more thing to check whether the HDFS has enough space for your data. I can upload a small file but failed to upload a big file (30GB) to HDFS. 'bin/hdfs dfsadmin -report' shows that each data node only has a few GB available.

Answer 2

Reformatting the node is not the solution. You will have to edit the start-all.sh. Start the dfs, wait for it to start completely and then start mapred. You can do this using a sleep. Waiting for 1 second worked for me. See the complete solution here http://sonalgoyal.blogspot.com/2009/06/hadoop-on-ubuntu.html.

Answer 3

It's about SELINUX. In My cases, CentOS 6.5

All node(name, second, data....)

service iptables stop

Answer 4

Have you tried the recommend from the wiki http://wiki.apache.org/hadoop/HowToSetupYourDevelopmentEnvironment ?

I was getting this error when putting data into the dfs. The solution is strange and probably inconsistent: I erased all temporary data along with the namenode, reformatted the namenode, started everything up, and visited my "cluster's" dfs health page (http://your_host:50070/dfshealth.jsp). The last step, visiting the health page, is the only way I can get around the error. Once I've visited the page, putting and getting files in and out of the dfs works great!