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https://issues.apache.org/jira/browse/HDFS-7314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14195968#comment-14195968
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Hadoop QA commented on HDFS-7314:
---------------------------------
{color:green}+1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12679168/HDFS-7314.patch
against trunk revision 2bb327e.
{color:green}+1 @author{color}. The patch does not contain any @author
tags.
{color:green}+1 tests included{color}. The patch appears to include 1 new
or modified test files.
{color:green}+1 javac{color}. The applied patch does not increase the
total number of javac compiler warnings.
{color:green}+1 javadoc{color}. There were no new javadoc warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with
eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new
Findbugs (version 2.0.3) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase
the total number of release audit warnings.
{color:green}+1 core tests{color}. The patch passed unit tests in
hadoop-hdfs-project/hadoop-hdfs.
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-HDFS-Build/8638//testReport/
Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/8638//console
This message is automatically generated.
> Aborted DFSClient's impact on long running service like YARN
> ------------------------------------------------------------
>
> Key: HDFS-7314
> URL: https://issues.apache.org/jira/browse/HDFS-7314
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Ming Ma
> Assignee: Ming Ma
> Attachments: HDFS-7314.patch
>
>
> It happened in YARN nodemanger scenario. But it could happen to any long
> running service that use cached instance of DistrbutedFileSystem.
> 1. Active NN is under heavy load. So it became unavailable for 10 minutes;
> any DFSClient request will get ConnectTimeoutException.
> 2. YARN nodemanager use DFSClient for certain write operation such as log
> aggregator or shared cache in YARN-1492. DFSClient used by YARN NM's
> renewLease RPC got ConnectTimeoutException.
> {noformat}
> 2014-10-29 01:36:19,559 WARN org.apache.hadoop.hdfs.LeaseRenewer: Failed to
> renew lease for [DFSClient_NONMAPREDUCE_-550838118_1] for 372 seconds.
> Aborting ...
> {noformat}
> 3. After DFSClient is in Aborted state, YARN NM can't use that cached
> instance of DistributedFileSystem.
> {noformat}
> 2014-10-29 20:26:23,991 INFO
> org.apache.hadoop.yarn.server.nodemanager.containermanager.localizer.ResourceLocalizationService:
> Failed to download rsrc...
> java.io.IOException: Filesystem closed
> at org.apache.hadoop.hdfs.DFSClient.checkOpen(DFSClient.java:727)
> at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1780)
> at
> org.apache.hadoop.hdfs.DistributedFileSystem$17.doCall(DistributedFileSystem.java:1124)
> at
> org.apache.hadoop.hdfs.DistributedFileSystem$17.doCall(DistributedFileSystem.java:1120)
> at
> org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
> at
> org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1120)
> at org.apache.hadoop.yarn.util.FSDownload.copy(FSDownload.java:237)
> at org.apache.hadoop.yarn.util.FSDownload.call(FSDownload.java:340)
> at org.apache.hadoop.yarn.util.FSDownload.call(FSDownload.java:57)
> at java.util.concurrent.FutureTask.run(FutureTask.java:262)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
> at java.util.concurrent.FutureTask.run(FutureTask.java:262)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> We can make YARN or DFSClient more tolerant to temporary NN unavailability.
> Given the callstack is YARN -> DistributedFileSystem -> DFSClient, this can
> be addressed at different layers.
> * YARN closes the DistributedFileSystem object when it receives some well
> defined exception. Then the next HDFS call will create a new instance of
> DistributedFileSystem. We have to fix all the places in YARN. Plus other HDFS
> applications need to address this as well.
> * DistributedFileSystem detects Aborted DFSClient and create a new instance
> of DFSClient. We will need to fix all the places DistributedFileSystem calls
> DFSClient.
> * After DFSClient gets into Aborted state, it doesn't have to reject all
> requests , instead it can retry. If NN is available again it can transition
> to healthy state.
> Comments?
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