[HDFS-9046] Any Error during BPOfferService run can leads to Missing DN.

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Assignee: nijel
• Reporter: nijel
• Created: 10/Sep/15 14:10
• Updated: 29/Jan/16 19:32

Description

The cluster is ins HA mode and each DN having only one block pool.

The issue is once after switch one DN is missing from the current active NN.
Upon analysis I found that there is one exception in BPOfferService.run()

2015-08-21 09:02:11,190 | WARN  | DataNode: [[[DISK]file:/srv/BigData/hadoop/data5/dn/ [DISK]file:/srv/BigData/hadoop/data4/dn/]]  heartbeating to 160-149-0-114/160.149.0.114:25000 | Unexpected exception in block pool Block pool BP-284203724-160.149.0.114-1438774011693 (Datanode Uuid 15ce1dd7-227f-4fd2-9682-091aa6bc2b89) service to 160-149-0-114/160.149.0.114:25000 | BPServiceActor.java:830
java.lang.OutOfMemoryError: unable to create new native thread
                at java.lang.Thread.start0(Native Method)
                at java.lang.Thread.start(Thread.java:714)
                at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:950)
                at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1357)
                at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetAsyncDiskService.execute(FsDatasetAsyncDiskService.java:172)
                at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetAsyncDiskService.deleteAsync(FsDatasetAsyncDiskService.java:221)
                at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.invalidate(FsDatasetImpl.java:1887)
                at org.apache.hadoop.hdfs.server.datanode.BPOfferService.processCommandFromActive(BPOfferService.java:669)
                at org.apache.hadoop.hdfs.server.datanode.BPOfferService.processCommandFromActor(BPOfferService.java:616)
                at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.processCommand(BPServiceActor.java:856)
                at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.offerService(BPServiceActor.java:671)
                at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:822)
                at java.lang.Thread.run(Thread.java:745)

After this particular BPOfferService is down during the run time.
And this particular NN will not have the details of this DN

Similar issues are discussed in the following JIRAs
https://issues.apache.org/jira/browse/HDFS-2882
https://issues.apache.org/jira/browse/HDFS-7714

Can we retry in this case also with a larger interval instead of shutting down this BPOfferService ?
I think since this exceptions can occur randomly in DN it is not good to keep the DN running where some NN does not have the info !

Issue Links

• is duplicated by: HDFS-9684 DataNode stopped sending heartbeat after getting OutOfMemoryError form DataTransfer thread.