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https://issues.apache.org/jira/browse/HDFS-12749?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16375299#comment-16375299
]
He Xiaoqiao commented on HDFS-12749:
------------------------------------
[~xkrogen] Thanks for your review and comments.
{quote}Are you running without Kerberos? Do you see a relevant WARN statement
from the log for ipc.Client?
{quote}
a. This is security cluster with Kerberos,
b. All relevant WARN or EXCEPTION depict as [~tanyuxin] mentioned above
(description & second comment.)
Based on the exception logs that [~tanyuxin] provided, I think
{{SocketTimeoutException}} was over-wrapped in extra {{IOException}} by
{{Client#cleanupCalls}}, the following notes based branch-2.7 (maybe I am
wrong, if that please correct me.)
a. Client#call (line:1448) throws {{IOException}} which wrapped
{{SocketTimeoutException}} when {{call.error}} is not null and it is not
instance of {{RemoteException}}, thus this exception is wrapped by
{{NetUtils#wrapException}}:
{code:java}
public Writable call(RPC.RpcKind rpcKind, Writable rpcRequest,
ConnectionId remoteId, int serviceClass,
AtomicBoolean fallbackToSimpleAuth) throws IOException {
final Call call = createCall(rpcKind, rpcRequest);
Connection connection = getConnection(remoteId, call, serviceClass,
fallbackToSimpleAuth);
try {
connection.sendRpcRequest(call); // send the rpc request
} catch (RejectedExecutionException e) {
throw new IOException("connection has been closed", e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
LOG.warn("interrupted waiting to send rpc request to server", e);
throw new IOException(e);
}
synchronized (call) {
while (!call.done) {
try {
call.wait(); // wait for the result
} catch (InterruptedException ie) {
Thread.currentThread().interrupt();
throw new InterruptedIOException("Call interrupted");
}
}
if (call.error != null) {
if (call.error instanceof RemoteException) {
call.error.fillInStackTrace();
throw call.error;
} else { // local exception
InetSocketAddress address = connection.getRemoteAddress();
throw NetUtils.wrapException(address.getHostName(),
address.getPort(),
NetUtils.getHostname(),
0,
call.error);
}
} else {
return call.getRpcResponse();
}
}
}
{code}
b. {{NetUtils#wrapException}} can distinguish {{SocketTimeoutException}} if
{{call.error}} is instance of, but not actually so logs `Failed on local
exception: java.io.IOException: ...`
c. {{call.error}} is set only by client#setException which invoked by
{{Client#receiveRpcResponse}} and {{Client#cleanupCalls}}, however
{{call.error}} is set RemoteException always in {{Client#receiveRpcResponse}}.
Evidently, the only possibility is that {{SocketTimeoutException}} was
over-wrapped in {{IOException}} by {{Client#cleanupCalls}}.
d.The key point in {{Client#cleanupCalls}} is {{#closeException}} which is set
by {{Client#markClosed}} invoked by {{Client#sendRpcRequest}} and it catch all
{{IOException}} then set {{#closeException}} equal it.
{code:java}
public void sendRpcRequest(final Call call)
throws InterruptedException, IOException {
......
synchronized (sendRpcRequestLock) {
Future<?> senderFuture = sendParamsExecutor.submit(new Runnable() {
@Override
public void run() {
try {
......
} catch (IOException e) {
// exception at this point would leave the connection in an
// unrecoverable state (eg half a call left on the wire).
// So, close the connection, killing any outstanding calls
markClosed(e);
} finally {
//the buffer is just an in-memory buffer, but it is still polite
to
// close early
IOUtils.closeStream(d);
}
}
});
.....
}
}
{code}
[~xkrogen],[~kihwal] any suggestions?
> 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
> 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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