Hadoop error stalling job reduce process - hadoop

I have been running a Hadoop job(word count example) a few times on my two-node cluster setup, and it´s been working fine up until now. I keep getting a RuntimeException which stalls the reduce process at 19%:
2013-04-13 18:45:22,191 INFO org.apache.hadoop.mapred.Task: Task:attempt_201304131843_0001_m_000000_0 is done. And is in the process of commiting
2013-04-13 18:45:22,299 INFO org.apache.hadoop.mapred.Task: Task 'attempt_201304131843_0001_m_000000_0' done.
2013-04-13 18:45:22,318 INFO org.apache.hadoop.mapred.TaskLogsTruncater: Initializing logs' truncater with mapRetainSize=-1 and reduceRetainSize=-1
2013-04-13 18:45:23,181 WARN org.apache.hadoop.mapred.Child: Error running child
java.lang.RuntimeException: Error while running command to get file permissions : org.apache.hadoop.util.Shell$ExitCodeException:
at org.apache.hadoop.util.Shell.runCommand(Shell.java:255)
at org.apache.hadoop.util.Shell.run(Shell.java:182)
at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:375)
at org.apache.hadoop.util.Shell.execCommand(Shell.java:461)
at org.apache.hadoop.util.Shell.execCommand(Shell.java:444)
at org.apache.hadoop.fs.FileUtil.execCommand(FileUtil.java:710)
at org.apache.hadoop.fs.RawLocalFileSystem$RawLocalFileStatus.loadPermissionInfo(RawLocalFileSystem.java:443)
at org.apache.hadoop.fs.RawLocalFileSystem$RawLocalFileStatus.getOwner(RawLocalFileSystem.java:426)
at org.apache.hadoop.mapred.TaskLog.obtainLogDirOwner(TaskLog.java:267)
at org.apache.hadoop.mapred.TaskLogsTruncater.truncateLogs(TaskLogsTruncater.java:124)
at org.apache.hadoop.mapred.Child$4.run(Child.java:260)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1149)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
at org.apache.hadoop.fs.RawLocalFileSystem$RawLocalFileStatus.loadPermissionInfo(RawLocalFileSystem.java:468)
at org.apache.hadoop.fs.RawLocalFileSystem$RawLocalFileStatus.getOwner(RawLocalFileSystem.java:426)
at org.apache.hadoop.mapred.TaskLog.obtainLogDirOwner(TaskLog.java:267)
at org.apache.hadoop.mapred.TaskLogsTruncater.truncateLogs(TaskLogsTruncater.java:124)
at org.apache.hadoop.mapred.Child$4.run(Child.java:260)
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:1149)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
Has anyone any ideas of what might be causing this?
Edit: Solved it myself.
If anyone else runs into the same problem, this was caused by the etc/hosts file on the master-node. I hadn´t entered the host-name and address of the slave-node.
This is how my hosts-file is structured on the master-node:
127.0.0.1 MyUbuntuServer
192.xxx.x.xx2 master
192.xxx.x.xx3 MySecondUbuntuServer
192.xxx.x.xx3 slave

a similar problem is described here:
http://comments.gmane.org/gmane.comp.apache.mahout.user/8898
The info there might be related to other version of hadoop. It says:
java.lang.RuntimeException: Error while running command to
get file permissions : java.io.IOException: Cannot run program
"/bin/ls": error=12, Not enough space
The solution their was to change heapsize through mapred.child.java.opts* *-Xmx1200M
See also: https://groups.google.com/a/cloudera.org/forum/?fromgroups=#!topic/cdh-user/BHGYJDNKMGE
HTH,
Avner

Related

hadoop distcp exception can't rename tmp file

I am trying to move data from one cdh(CDH4.7.1) cluster to another cdh(cdh5.4.1) cluster using distcp command as below :
hadoop distcp -D mapred.task.timeout=60000000 -update hdfs://namenodeIp of source(CDH4):8020/user/admin/distcptest1 webhdfs://namenodeIp of target(CDH5):50070/user/admin/testdir
With this command directories and subdirectories are copied from source cluster cdh4 to target cluster cdh5 but files from source cluster are not being copied to target cluster failing with the below error:
Fail to rename tmp file (=webhdfs://10.10.200.221:50070/user/admin/testdir/_distcp_tmp_g79i9w/distcptest1/account.xlsx) to destination file (=webhdfs://10.10.200.221:50070/user/admin/testdir/distcptest1/account.xlsx)
The stacktrace found in the logs of that job is as follows:
2016-02-19 03:16:57,006 WARN mapreduce.Counters: Group org.apache.hadoop.mapred.Task$Counter is deprecated. Use org.apache.hadoop.mapreduce.TaskCounter instead
2016-02-19 03:16:58,686 WARN org.apache.hadoop.conf.Configuration: session.id is deprecated. Instead, use dfs.metrics.session-id
2016-02-19 03:16:58,693 INFO org.apache.hadoop.metrics.jvm.JvmMetrics: Initializing JVM Metrics with processName=MAP, sessionId=
2016-02-19 03:16:59,736 INFO org.apache.hadoop.util.ProcessTree: setsid exited with exit code 0
2016-02-19 03:16:59,752 INFO org.apache.hadoop.mapred.Task: Using ResourceCalculatorPlugin : org.apache.hadoop.util.LinuxResourceCalculatorPlugin#715f1f9c
2016-02-19 03:17:00,248 INFO org.apache.hadoop.mapred.MapTask: Processing split: hdfs://n1.quadratics.com:8020/user/admin/.stagingdistcp_g79i9w/_distcp_src_files:0+2443
2016-02-19 03:17:00,345 WARN mapreduce.Counters: Counter name MAP_INPUT_BYTES is deprecated. Use FileInputFormatCounters as group name and BYTES_READ as counter name instead
2016-02-19 03:17:00,353 INFO org.apache.hadoop.mapred.MapTask: numReduceTasks: 0
2016-02-19 03:17:01,098 INFO org.apache.hadoop.tools.DistCp: FAIL distcptest1/account.xlsx : java.io.IOException: Fail to rename tmp file (=webhdfs://10.10.200.221:50070/user/admin/testdir/_distcp_tmp_g79i9w/distcptest1/account.xlsx) to destination file (=webhdfs://10.10.200.221:50070/user/admin/testdir/distcptest1/account.xlsx)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.rename(DistCp.java:494)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.copy(DistCp.java:463)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.map(DistCp.java:549)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.map(DistCp.java:316)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:417)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:332)
at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1438)
at org.apache.hadoop.mapred.Child.main(Child.java:262)
Caused by: java.io.IOException
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.rename(DistCp.java:490)
... 11 more
2016-02-19 03:17:10,457 INFO org.apache.hadoop.tools.DistCp: FAIL distcptest1/_distcp_logs_ww86cq/_logs/history/job_201602160057_0105_1455872921915_hdfs_distcp : java.io.IOException: Fail to rename tmp file (=webhdfs://10.10.200.221:50070/user/admin/testdir/_distcp_tmp_g79i9w/distcptest1/_distcp_logs_ww86cq/_logs/history/job_201602160057_0105_1455872921915_hdfs_distcp) to destination file (=webhdfs://10.10.200.221:50070/user/admin/testdir/distcptest1/_distcp_logs_ww86cq/_logs/history/job_201602160057_0105_1455872921915_hdfs_distcp)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.rename(DistCp.java:494)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.copy(DistCp.java:463)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.map(DistCp.java:549)
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.map(DistCp.java:316)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:417)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:332)
at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1438)
at org.apache.hadoop.mapred.Child.main(Child.java:262)
Caused by: java.io.IOException
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.rename(DistCp.java:490)
... 11 more
Got the above error even after using this command as well:
hadoop distcp -D mapred.task.timeout=60000000 -update webhdfs://namenodeIp of source(CDH4):50070/user/admin/distcptest1 webhdfs://namenodeIp of target(CDH5):50070/user/admin/testdir
WebHDFS is enabled in both the clusters.
Regarding execution of the distcp command I did that from my source cluster that is cdh4 with user as 'admin' and its possible as per the cloudera link given below:
http://www.cloudera.com/documentation/enterprise/5-4-x/topics/cdh_admin_distcp_data_cluster_migrate.html
When I monitored target cluster file from source cluster is not being written to temporary folder created by distcp in target cluster.That's the reason why rename is failing in the target cluster since the target path doesn't contain that file.Can someone tell why file writing is failing ?
I've searched related posts on stackoverflow and tried those solutions but none of them couldn't fix this problem.Any ideas of fixing this would be of great help.
HDFS is a user that is not able to run yarn jobs, it will most likely be a banned user in your YARN config.
If this is a secure cluster, you need a trust between both kerberos domains aswell.

Yarn MapReduce approximate-pi example fails exit code 1 when run as non-hadoop user

I am running a small private cluster of linux machines with Hadoop 2.6.2 and yarn. I launch yarn jobs from a linux edge node. The canned Yarn example to approximate the value of pi works perfectly when run by the hadoop (superuser, owner of the cluster) user, but fails when run from my personal account on the edge node. In both cases (hadoop, me) I run the job exactly like this:
clott#edge: /home/hadoop/hadoop-2.6.2/bin/yarn jar /home/hadoop/hadoop-2.6.2/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.2.jar pi 2 5
It fails; the full output is below. I think the file-not-found exception is totally bogus. I think something causes the launch of the container to fail, and so there's no output to be found. What causes container launches to fail, and how can this be debugged?
Because this identical same command works perfectly when run by the hadoop user but not when run by a different account on the same edge node, I suspect a permission or other yarn configuration problem; I don't suspect a missing-jar file problem. My personal account uses the same environment variables as the hadoop account, for what that's worth.
These questions are similar but I didn't find a solution:
https://issues.cloudera.org/browse/DISTRO-577
Running a map reduce job as a different user
Yarn MapReduce Job Issue - AM Container launch error in Hadoop 2.3.0
I have tried these remedies without any success:
In core-site.xml, set the value of hadoop.tmp.dir to /tmp/temp-${user.name}
Add my personal user account to every node in the cluster
I guess that many installations run with just a single user, but I'm trying to allow two people to work together on the cluster without trashing each other's intermediate results. Am I totally nuts?
Full output:
Number of Maps = 2
Samples per Map = 5
Wrote input for Map #0
Wrote input for Map #1
Starting Job
15/12/22 15:29:18 INFO client.RMProxy: Connecting to ResourceManager at ac1.mycompany.com/1.2.3.4:8032
15/12/22 15:29:18 INFO input.FileInputFormat: Total input paths to process : 2
15/12/22 15:29:19 INFO mapreduce.JobSubmitter: number of splits:2
15/12/22 15:29:19 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1450815437271_0002
15/12/22 15:29:19 INFO impl.YarnClientImpl: Submitted application application_1450815437271_0002
15/12/22 15:29:19 INFO mapreduce.Job: The url to track the job: http://ac1.mycompany.com:8088/proxy/application_1450815437271_0002/
15/12/22 15:29:19 INFO mapreduce.Job: Running job: job_1450815437271_0002
15/12/22 15:29:31 INFO mapreduce.Job: Job job_1450815437271_0002 running in uber mode : false
15/12/22 15:29:31 INFO mapreduce.Job: map 0% reduce 0%
15/12/22 15:29:31 INFO mapreduce.Job: Job job_1450815437271_0002 failed with state FAILED due to: Application application_1450815437271_0002 failed 2 times due to AM Container for appattempt_1450815437271_0002_000002 exited with exitCode: 1
For more detailed output, check application tracking page:http://ac1.mycompany.com:8088/proxy/application_1450815437271_0002/Then, click on links to logs of each attempt.
Diagnostics: Exception from container-launch.
Container id: container_1450815437271_0002_02_000001
Exit code: 1
Stack trace: ExitCodeException exitCode=1:
at org.apache.hadoop.util.Shell.runCommand(Shell.java:538)
at org.apache.hadoop.util.Shell.run(Shell.java:455)
at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:715)
at org.apache.hadoop.yarn.server.nodemanager.DefaultContainerExecutor.launchContainer(DefaultContainerExecutor.java:211)
at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:302)
at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:82)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Container exited with a non-zero exit code 1
Failing this attempt. Failing the application.
15/12/22 15:29:31 INFO mapreduce.Job: Counters: 0
Job Finished in 13.489 seconds
java.io.FileNotFoundException: File does not exist: hdfs://ac1.mycompany.com/user/clott/QuasiMonteCarlo_1450816156703_163431099/out/reduce-out
at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1122)
at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1114)
at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1114)
at org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1817)
at org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1841)
at org.apache.hadoop.examples.QuasiMonteCarlo.estimatePi(QuasiMonteCarlo.java:314)
at org.apache.hadoop.examples.QuasiMonteCarlo.run(QuasiMonteCarlo.java:354)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at org.apache.hadoop.examples.QuasiMonteCarlo.main(QuasiMonteCarlo.java:363)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:71)
at org.apache.hadoop.util.ProgramDriver.run(ProgramDriver.java:144)
at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:74)
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.util.RunJar.run(RunJar.java:221)
at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Yes Manjunath Ballur you were right it was a permissions problem! Finally learned how to preserve the yarn application logs, which clearly revealed the problem. Here are the steps:
Edit yarn-site.xml and add a property to delay yarn log deletion:
<property>
<name>yarn.nodemanager.delete.debug-delay-sec</name>
<value>600</value>
</property>
Push yarn-site.xml to all nodes (ARGH I forgot this for a long time) and restart cluster.
Run yarn example to estimate pi as shown above, it fails. Look at http://namenode:8088/cluster/apps/FAILED to see the failed application, click on the link for the most recent failure, look at the bottom to see which nodes in the cluster were used.
Open a window on one of the nodes in the cluster where the app failed. Find the job directory, which in my case was
~hadoop/hadoop-2.6.2/logs/userlogs/application_1450815437271_0004/container_1450‌​815437271_0004_01_000001/
Et voila, I saw files stdout (only log4j bitching), stderr (nearly empty) and syslog (winner winner chicken dinner). In the syslog file I found this gem:
2015-12-23 08:31:42,376 INFO [main] org.apache.hadoop.service.AbstractService: Service JobHistoryEventHandler failed in state INITED; cause: org.apache.hadoop.yarn.exceptions.YarnRuntimeException: org.apache.hadoop.security.AccessControlException: Permission denied: user=clott, access=EXECUTE, inode="/tmp/hadoop-yarn/staging/history":hadoop:supergroup:drwxrwx---
So the problem was permissions on hdfs:///tmp/hadoop-yarn/staging/history. A simple chmod 777 put me right, I'm not fighting the group perms anymore. Now a non-hadoop non-superuser can run a yarn job.

Missing block in Hadoop

I am trying to run a wordcount job in Hadoop. Due to a previous error, I had to turn off the safe mode for the NameNode. Now, however, when trying to run the job, I am getting the following error:
14/08/06 14:49:08 INFO mapreduce.Job: map 1% reduce 0%
14/08/06 14:49:25 INFO mapreduce.Job: Task Id : attempt_1407336345567_0002_m_000158_0, Status : FAILED
Error: org.apache.hadoop.hdfs.BlockMissingException: Could not obtain block: BP-971868671-192.168.50.2-1406571670535:blk_1073743276_2475 file=/wikidumps/enwiki-20130904-pages-meta-history3.xml-p000032706p000037161
at org.apache.hadoop.hdfs.DFSInputStream.chooseDataNode(DFSInputStream.java:838)
at org.apache.hadoop.hdfs.DFSInputStream.blockSeekTo(DFSInputStream.java:526)
at org.apache.hadoop.hdfs.DFSInputStream.readWithStrategy(DFSInputStream.java:749)
at org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:793)
at java.io.DataInputStream.read(DataInputStream.java:100)
at org.apache.hadoop.util.LineReader.readDefaultLine(LineReader.java:211)
at org.apache.hadoop.util.LineReader.readLine(LineReader.java:174)
at org.apache.hadoop.mapreduce.lib.input.LineRecordReader.nextKeyValue(LineRecordReader.java:164)
at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:532)
at org.apache.hadoop.mapreduce.task.MapContextImpl.nextKeyValue(MapContextImpl.java:80)
at org.apache.hadoop.mapreduce.lib.map.WrappedMapper$Context.nextKeyValue(WrappedMapper.java:91)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:763)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:162)
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.mapred.YarnChild.main(YarnChild.java:157)
The log files are not showing any particular error. Does anyone know the reason for this error? Thanks in advance!

Successful Hadoop job with errors

I have set up my first simple Hadoop multi-node cluster(I am a newbie) consisting of two nodes, a master-node(also acting as slave-node) and a dedicated slave-node.
I am running a Hadoop "word count" example job, which finishes successfully. Although when i look in the logs i can see an error, this is from TaskTracker log on slave-node:
2013-04-12 00:30:16,436 WARN org.apache.hadoop.mapred.TaskTracker: Failed validating JVM
java.io.IOException: JvmValidate Failed. Ignoring request from task:
attempt_201304112309_0006_m_000003_0, with JvmId: jvm_201304112309_0006_m_1485441759
at org.apache.hadoop.mapred.TaskTracker.validateJVM(TaskTracker.java:3434)
at org.apache.hadoop.mapred.TaskTracker.statusUpdate(TaskTracker.java:3504)
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:601)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:578)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1393)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1389)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1149)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1387)
2013-04-12 00:30:16,515 WARN org.apache.hadoop.mapred.DefaultTaskController: Exit code from task is : 143
2013-04-12 00:30:16,515 INFO org.apache.hadoop.mapred.DefaultTaskController: Output from DefaultTaskController's launchTask follows:
2013-04-12 00:30:16,515 INFO org.apache.hadoop.mapred.TaskController:
2013-04-12 00:30:16,516 INFO org.apache.hadoop.mapred.JvmManager: JVM : jvm_201304112309_0006_m_1485441759 exited with exit code 143. Number of tasks it ran: 1
Do anyone know what happens here?
Sorry about the ugly code indentation, i couldn´t figure out how to do it properly, this is my first post.
It looks like something killed your process, but you mentioned that it finished so Hadoops resilient features kicked in and either ran it on another node or retried it on the same getting your word count done either way. check out the answer to JVM error code 143

Error writing event data into HDFS through flume

I am using cdh3 update 4 tarball for development purpose. I have hadoop up and running. Now, I also downloaded equivalent flume tarball from cloudera viz 1.1.0 and tried writing a tail of log file into hdfs using hdfs-sink. When I run the flume agent, it starts okay but ends up in error when it attempts writing the new event data into hdfs. I couldn't find better group to post this question than stackoverflow.
here is flume configuration I am using
agent.sources=exec-source
agent.sinks=hdfs-sink
agent.channels=ch1
agent.sources.exec-source.type=exec
agent.sources.exec-source.command=tail -F /locationoffile
agent.sinks.hdfs-sink.type=hdfs
agent.sinks.hdfs-sink.hdfs.path=hdfs://localhost:8020/flume
agent.sinks.hdfs-sink.hdfs.filePrefix=apacheaccess
agent.channels.ch1.type=memory
agent.channels.ch1.capacity=1000
agent.sources.exec-source.channels=ch1
agent.sinks.hdfs-sink.channel=ch1
Also, this is a small snippet of error that gets displayed in console when it receives new event data and tries writing it into hdfs.
13/03/16 17:59:21 INFO hdfs.BucketWriter: Creating hdfs://localhost:8020/user/hdfs-user/flume/apacheaccess.1363436060424.tmp
13/03/16 17:59:22 WARN hdfs.HDFSEventSink: HDFS IO error
java.io.IOException: Failed on local exception: java.io.IOException: Broken pipe; Host Details : local host is: "sumit-HP-Pavilion-dv3-Notebook-PC/127.0.0.1"; destination host is: "localhost":8020;
at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:759)
at org.apache.hadoop.ipc.Client.call(Client.java:1164)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:202)
at $Proxy9.create(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:164)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:83)
at $Proxy9.create(Unknown Source)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.create(ClientNamenodeProtocolTranslatorPB.java:192)
at org.apache.hadoop.hdfs.DFSOutputStream.<init>(DFSOutputStream.java:1298)
at org.apache.hadoop.hdfs.DFSOutputStream.newStreamForCreate(DFSOutputStream.java:1317)
at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:1215)
at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:1173)
at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:272)
at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:261)
at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:78)
at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:805)
at org.apache.hadoop.io.SequenceFile$Writer.<init>(SequenceFile.java:1060)
at org.apache.hadoop.io.SequenceFile.createWriter(SequenceFile.java:270)
at org.apache.hadoop.io.SequenceFile.createWriter(SequenceFile.java:369)
at org.apache.flume.sink.hdfs.HDFSSequenceFile.open(HDFSSequenceFile.java:65)
at org.apache.flume.sink.hdfs.HDFSSequenceFile.open(HDFSSequenceFile.java:49)
at org.apache.flume.sink.hdfs.BucketWriter.doOpen(BucketWriter.java:190)
at org.apache.flume.sink.hdfs.BucketWriter.access$000(BucketWriter.java:50)
at org.apache.flume.sink.hdfs.BucketWriter$1.run(BucketWriter.java:157)
at org.apache.flume.sink.hdfs.BucketWriter$1.run(BucketWriter.java:154)
at org.apache.flume.sink.hdfs.BucketWriter.runPrivileged(BucketWriter.java:127)
at org.apache.flume.sink.hdfs.BucketWriter.open(BucketWriter.java:154)
at org.apache.flume.sink.hdfs.BucketWriter.append(BucketWriter.java:316)
at org.apache.flume.sink.hdfs.HDFSEventSink$1.call(HDFSEventSink.java:718)
at org.apache.flume.sink.hdfs.HDFSEventSink$1.call(HDFSEventSink.java:715)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.io.IOException: Broken pipe
at sun.nio.ch.FileDispatcher.write0(Native Method)
at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:29)
at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:100)
at sun.nio.ch.IOUtil.write(IOUtil.java:71)
at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:334)
at org.apache.hadoop.net.SocketOutputStream$Writer.performIO(SocketOutputStream.java:62)
at org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:143)
at org.apache.hadoop.net.SocketOutputStream.write(SocketOutputStream.java:153)
at org.apache.hadoop.net.SocketOutputStream.write(SocketOutputStream.java:114)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
at java.io.DataOutputStream.flush(DataOutputStream.java:106)
at org.apache.hadoop.ipc.Client$Connection.sendParam(Client.java:861)
at org.apache.hadoop.ipc.Client.call(Client.java:1141)
... 37 more
13/03/16 17:59:27 INFO hdfs.BucketWriter: Creating hdfs://localhost:8020/user/hdfs-user/flume/apacheaccess.1363436060425.tmp
13/03/16 17:59:27 WARN hdfs.HDFSEventSink: HDFS IO error
java.io.IOException: Failed on local exception: java.io.IOException: Broken pipe; Host Details : local host is: "sumit-HP-Pavilion-dv3-Notebook-PC/127.0.0.1"; destination host is: "localhost":8020;
As people in cloudera mail list suggest, there are probable reasons of this error:
The HDFS safemode is turned on. Try to run hadoop fs -safemode leave and see if the error goes away.
Flume and Hadoop versions are mismatched. To check this replace the hadoop-core.jar in flume/lib directory with the one found in hadoop's installation folder.

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