Patrick Dignan created HBASE-17501:
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Summary: NullPointerException after Datanodes Decommissioned and
Terminated
Key: HBASE-17501
URL: https://issues.apache.org/jira/browse/HBASE-17501
Project: HBase
Issue Type: Bug
Environment: CentOS Derivative with a derivative of the 3.18.43
kernel. HBase on CDH5.9.0 with some patches. HDFS CDH 5.9.0 with no patches.
Reporter: Patrick Dignan
Priority: Minor
Hello everyone,
We recently encountered an interesting NullPointerException in HDFS that
bubbles up to HBase, and is resolved be restarting the regionserver. The issue
was exhibited while we were replacing a set of nodes in one of our clusters
with a new set. We did the following:
1. Turn off the HBase balancer
2. Gracefully move the regions off the nodes we’re shutting off using a tool we
wrote to do so
3. Decommission the datanodes using the HDFS exclude hosts file and hdfs
dfsadmin -refreshNodes
4. Wait for the datanodes to decommission fully
5. Terminate the VMs the instances are running inside.
A few notes. We did not shutdown the datanode processes, and the nodes were
therefore not marked as dead by the namenode. We simply terminated the
datanode VM (in this case an AWS instance). The nodes were marked as
decommissioned. We are running our clusters with DNS, and when we terminate
VMs, the associated CName is removed and no longer resolves. The errors do not
seem to resolve without a restart.
After we did this, the remaining regionservers started throwing
NullPointerExceptions with the following stack trace:
2017-01-19 23:09:05,638 DEBUG org.apache.hadoop.hbase.ipc.RpcServer:
RpcServer.RW.fifo.Q.read.handler=80,queue=14,port=60020: callId: 1727723891
service: ClientService methodName: Scan size: 216 connection:
172.16.36.128:31538
java.io.IOException
at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2214)
at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:123)
at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:204)
at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:183)
Caused by: java.lang.NullPointerException
at org.apache.hadoop.hdfs.DFSInputStream.seek(DFSInputStream.java:1564)
at org.apache.hadoop.fs.FSDataInputStream.seek(FSDataInputStream.java:62)
at
org.apache.hadoop.hbase.io.hfile.HFileBlock$AbstractFSReader.readAtOffset(HFileBlock.java:1434)
at
org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl.readBlockDataInternal(HFileBlock.java:1682)
at
org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl.readBlockData(HFileBlock.java:1542)
at
org.apache.hadoop.hbase.io.hfile.HFileReaderV2.readBlock(HFileReaderV2.java:445)
at
org.apache.hadoop.hbase.io.hfile.HFileBlockIndex$BlockIndexReader.loadDataBlockWithScanInfo(HFileBlockIndex.java:266)
at
org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.seekTo(HFileReaderV2.java:642)
at
org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.seekTo(HFileReaderV2.java:592)
at
org.apache.hadoop.hbase.regionserver.StoreFileScanner.seekAtOrAfter(StoreFileScanner.java:294)
at
org.apache.hadoop.hbase.regionserver.StoreFileScanner.seek(StoreFileScanner.java:199)
at
org.apache.hadoop.hbase.regionserver.StoreScanner.seekScanners(StoreScanner.java:343)
at
org.apache.hadoop.hbase.regionserver.StoreScanner.<init>(StoreScanner.java:198)
at
org.apache.hadoop.hbase.regionserver.HStore.createScanner(HStore.java:2106)
at org.apache.hadoop.hbase.regionserver.HStore.getScanner(HStore.java:2096)
at
org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.<init>(HRegion.java:5544)
at
org.apache.hadoop.hbase.regionserver.HRegion.instantiateRegionScanner(HRegion.java:2569)
at
org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:2555)
at
org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:2536)
at
org.apache.hadoop.hbase.regionserver.RSRpcServices.scan(RSRpcServices.java:2405)
at
org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:33738)
at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2170)
... 3 more
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