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https://issues.apache.org/jira/browse/HDFS-12749?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16417802#comment-16417802
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He Xiaoqiao commented on HDFS-12749:
------------------------------------
Thanks [~kihwal] for your detailed comment.
{quote}You can keep your change in register() and simply add the same logic to
the processCommand()'s catch block. I.e. crack open the RemoteException and
stop the actor thread if it is one of the terminal exceptions.{quote}
I think it may not be able to resolve this issue when catch and crack
{{RemoteException}} for #processCommand, since #processCommand throws
{{IOException}} which wrap {{SocketTimeoutException}} as [~tanyuxin] mentioned
in description
{quote}java.io.IOException: Failed on local exception: java.io.IOException:
java.net.SocketTimeoutException: 60000 millis timeout while waiting for channel
to be ready for read. ch : java.nio.channels.SocketChannel{quote}
According to your suggestions, is it better to create new issue to push that
stop the actor thread if it meet some fatal or terminal exceptions?
> DN may not send block report to NN after NN restart
> ---------------------------------------------------
>
> Key: HDFS-12749
> URL: https://issues.apache.org/jira/browse/HDFS-12749
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: datanode
> Affects Versions: 2.7.1, 2.8.3, 2.7.5, 3.0.0, 2.9.1
> Reporter: TanYuxin
> Assignee: He Xiaoqiao
> Priority: Major
> Attachments: HDFS-12749-branch-2.7.002.patch,
> HDFS-12749-trunk.003.patch, HDFS-12749.001.patch
>
>
> Now our cluster have thousands of DN, millions of files and blocks. When NN
> restart, NN's load is very high.
> After NN restart，DN will call BPServiceActor#reRegister method to register.
> But register RPC will get a IOException since NN is busy dealing with Block
> Report. The exception is caught at BPServiceActor#processCommand.
> Next is the caught IOException:
> {code:java}
> WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Error processing
> datanode Command
> java.io.IOException: Failed on local exception: java.io.IOException:
> java.net.SocketTimeoutException: 60000 millis timeout while waiting for
> channel to be ready for read. ch : java.nio.channels.SocketChannel[connected
> local=/DataNode_IP:Port remote=NameNode_Host/IP:Port]; Host Details : local
> host is: "DataNode_Host/Datanode_IP"; destination host is:
> "NameNode_Host":Port;
> at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:773)
> at org.apache.hadoop.ipc.Client.call(Client.java:1474)
> at org.apache.hadoop.ipc.Client.call(Client.java:1407)
> at
> org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:229)
> at com.sun.proxy.$Proxy13.registerDatanode(Unknown Source)
> at
> org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolClientSideTranslatorPB.registerDatanode(DatanodeProtocolClientSideTranslatorPB.java:126)
> at
> org.apache.hadoop.hdfs.server.datanode.BPServiceActor.register(BPServiceActor.java:793)
> at
> org.apache.hadoop.hdfs.server.datanode.BPServiceActor.reRegister(BPServiceActor.java:926)
> at
> org.apache.hadoop.hdfs.server.datanode.BPOfferService.processCommandFromActor(BPOfferService.java:604)
> at
> org.apache.hadoop.hdfs.server.datanode.BPServiceActor.processCommand(BPServiceActor.java:898)
> at
> org.apache.hadoop.hdfs.server.datanode.BPServiceActor.offerService(BPServiceActor.java:711)
> at
> org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:864)
> at java.lang.Thread.run(Thread.java:745)
> {code}
> The un-catched IOException breaks BPServiceActor#register, and the Block
> Report can not be sent immediately.
> {code}
> /**
> * Register one bp with the corresponding NameNode
> * <p>
> * The bpDatanode needs to register with the namenode on startup in order
> * 1) to report which storage it is serving now and
> * 2) to receive a registrationID
> *
> * issued by the namenode to recognize registered datanodes.
> *
> * @param nsInfo current NamespaceInfo
> * @see FSNamesystem#registerDatanode(DatanodeRegistration)
> * @throws IOException
> */
> void register(NamespaceInfo nsInfo) throws IOException {
> // The handshake() phase loaded the block pool storage
> // off disk - so update the bpRegistration object from that info
> DatanodeRegistration newBpRegistration = bpos.createRegistration();
> LOG.info(this + " beginning handshake with NN");
> while (shouldRun()) {
> try {
> // Use returned registration from namenode with updated fields
> newBpRegistration = bpNamenode.registerDatanode(newBpRegistration);
> newBpRegistration.setNamespaceInfo(nsInfo);
> bpRegistration = newBpRegistration;
> break;
> } catch(EOFException e) { // namenode might have just restarted
> LOG.info("Problem connecting to server: " + nnAddr + " :"
> + e.getLocalizedMessage());
> sleepAndLogInterrupts(1000, "connecting to server");
> } catch(SocketTimeoutException e) { // namenode is busy
> LOG.info("Problem connecting to server: " + nnAddr);
> sleepAndLogInterrupts(1000, "connecting to server");
> }
> }
>
> LOG.info("Block pool " + this + " successfully registered with NN");
> bpos.registrationSucceeded(this, bpRegistration);
> // random short delay - helps scatter the BR from all DNs
> scheduler.scheduleBlockReport(dnConf.initialBlockReportDelay);
> }
> {code}
> But NameNode has processed registerDatanode successfully, so it won't ask DN
> to re-register again
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