[FLUME-2451] HDFS Sink Cannot Reconnect After NameNode Restart

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.4.0
• Component/s: File Channel, Sinks+Sources
• Labels: HDFS Sink

Environment

8 node CDH 4.2.2 (2.0.0-cdh4.2.2) cluster
All cluster machines are running Ubuntu 12.04 x86_64

• Assignee: Venkat Ranganathan
• Reporter: Andrew O'Neill
• Created: 26/Aug/14 20:32
• Updated: 19/Dec/17 23:27

Description

I am testing a simple flume setup with a Sequence Generator Source, a File Channel, and an HDFS Sink (see my flume.conf below). This configuration works as expected until I reboot the cluster’s NameNode or until I restart the HDFS service on the cluster. At this point, it appears that the Flume Agent cannot reconnect to HDFS and must be manually restarted.

Here is our flume.conf:

appserver.sources = rawtext
appserver.channels = testchannel
appserver.sinks = test_sink

appserver.sources.rawtext.type = seq
appserver.sources.rawtext.channels = testchannel

appserver.channels.testchannel.type = file
appserver.channels.testchannel.capacity = 10000000
appserver.channels.testchannel.minimumRequiredSpace = 214748364800
appserver.channels.testchannel.checkpointDir = /Users/aoneill/Desktop/testchannel/checkpoint
appserver.channels.testchannel.dataDirs = /Users/aoneill/Desktop/testchannel/data
appserver.channels.testchannel.maxFileSize = 20000000

appserver.sinks.test_sink.type = hdfs
appserver.sinks.test_sink.channel = testchannel
appserver.sinks.test_sink.hdfs.path = hdfs://cluster01:8020/user/aoneill/flumetest
appserver.sinks.test_sink.hdfs.closeTries = 3
appserver.sinks.test_sink.hdfs.filePrefix = events-
appserver.sinks.test_sink.hdfs.fileSuffix = .avro
appserver.sinks.test_sink.hdfs.fileType = DataStream
appserver.sinks.test_sink.hdfs.writeFormat = Text
appserver.sinks.test_sink.hdfs.inUsePrefix = inuse-
appserver.sinks.test_sink.hdfs.inUseSuffix = .avro
appserver.sinks.test_sink.hdfs.rollCount = 100000
appserver.sinks.test_sink.hdfs.rollInterval = 30
appserver.sinks.test_sink.hdfs.rollSize = 10485760

These are the two error message that the Flume Agent outputs constantly after the restart:

2014-08-26 10:47:24,572 (SinkRunner-PollingRunner-DefaultSinkProcessor) [ERROR - org.apache.flume.sink.hdfs.AbstractHDFSWriter.isUnderReplicated(AbstractHDFSWriter.java:96)] Unexpected error while checking replication factor
java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor7.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.flume.sink.hdfs.AbstractHDFSWriter.getNumCurrentReplicas(AbstractHDFSWriter.java:162)
at org.apache.flume.sink.hdfs.AbstractHDFSWriter.isUnderReplicated(AbstractHDFSWriter.java:82)
at org.apache.flume.sink.hdfs.BucketWriter.shouldRotate(BucketWriter.java:452)
at org.apache.flume.sink.hdfs.BucketWriter.append(BucketWriter.java:387)
at org.apache.flume.sink.hdfs.HDFSEventSink.process(HDFSEventSink.java:392)
at org.apache.flume.sink.DefaultSinkProcessor.process(DefaultSinkProcessor.java:68)
at org.apache.flume.SinkRunner$PollingRunner.run(SinkRunner.java:147)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:735)
at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:207)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:525)
at org.apache.hadoop.hdfs.DFSOutputStream.createSocketForPipeline(DFSOutputStream.java:1253)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.transfer(DFSOutputStream.java:891)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.addDatanode2ExistingPipeline(DFSOutputStream.java:881)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.setupPipelineForAppendOrRecovery(DFSOutputStream.java:982)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.processDatanodeError(DFSOutputStream.java:779)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:448)

and

2014-08-26 10:47:29,592 (SinkRunner-PollingRunner-DefaultSinkProcessor) [WARN - org.apache.flume.sink.hdfs.HDFSEventSink.process(HDFSEventSink.java:418)] HDFS IO error
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:735)
at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:207)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:525)
at org.apache.hadoop.hdfs.DFSOutputStream.createSocketForPipeline(DFSOutputStream.java:1253)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.transfer(DFSOutputStream.java:891)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.addDatanode2ExistingPipeline(DFSOutputStream.java:881)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.setupPipelineForAppendOrRecovery(DFSOutputStream.java:982)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.processDatanodeError(DFSOutputStream.java:779)
at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:448)

I can provide additional information if needed. Thank you very much for any insight you are able to provide into this problem.

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