[jira] [Created] (YARN-5214) Pending on synchronized method DirectoryCollection#checkDirs can hang NM's NodeStatusUpdater

["Junping Du (JIRA)" <ji...@apache.org>]

Junping Du created YARN-5214:
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             Summary: Pending on synchronized method DirectoryCollection#checkDirs can hang NM's NodeStatusUpdater
                 Key: YARN-5214
                 URL: https://issues.apache.org/jira/browse/YARN-5214
             Project: Hadoop YARN
          Issue Type: Bug
          Components: nodemanager
            Reporter: Junping Du
            Assignee: Junping Du
            Priority: Critical


In one cluster, we notice NM's heartbeat to RM is suddenly stopped and wait a while and marked LOST by RM. From the log, the NM daemon is still running, but jstack hints NM's NodeStatusUpdater thread get blocked:
1.  Node Status Updater thread get blocked by 0x000000008065eae8 
{noformat}
"Node Status Updater" #191 prio=5 os_prio=0 tid=0x00007f0354194000 nid=0x26fa waiting for monitor entry [0x00007f035945a000]
   java.lang.Thread.State: BLOCKED (on object monitor)
        at org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection.getFailedDirs(DirectoryCollection.java:170)
        - waiting to lock <0x000000008065eae8> (a org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection)
        at org.apache.hadoop.yarn.server.nodemanager.LocalDirsHandlerService.getDisksHealthReport(LocalDirsHandlerService.java:287)
        at org.apache.hadoop.yarn.server.nodemanager.NodeHealthCheckerService.getHealthReport(NodeHealthCheckerService.java:58)
        at org.apache.hadoop.yarn.server.nodemanager.NodeStatusUpdaterImpl.getNodeStatus(NodeStatusUpdaterImpl.java:389)
        at org.apache.hadoop.yarn.server.nodemanager.NodeStatusUpdaterImpl.access$300(NodeStatusUpdaterImpl.java:83)
        at org.apache.hadoop.yarn.server.nodemanager.NodeStatusUpdaterImpl$1.run(NodeStatusUpdaterImpl.java:643)
        at java.lang.Thread.run(Thread.java:745)
{noformat}

2. The actual holder of this lock is DiskHealthMonitor:
{noformat}
"DiskHealthMonitor-Timer" #132 daemon prio=5 os_prio=0 tid=0x00007f0397393000 nid=0x26bd runnable [0x00007f035e511000]
   java.lang.Thread.State: RUNNABLE
        at java.io.UnixFileSystem.createDirectory(Native Method)
        at java.io.File.mkdir(File.java:1316)
        at org.apache.hadoop.util.DiskChecker.mkdirsWithExistsCheck(DiskChecker.java:67)
        at org.apache.hadoop.util.DiskChecker.checkDir(DiskChecker.java:104)
        at org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection.verifyDirUsingMkdir(DirectoryCollection.java:340)
        at org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection.testDirs(DirectoryCollection.java:312)
        at org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection.checkDirs(DirectoryCollection.java:231)
        - locked <0x000000008065eae8> (a org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection)
        at org.apache.hadoop.yarn.server.nodemanager.LocalDirsHandlerService.checkDirs(LocalDirsHandlerService.java:389)
        at org.apache.hadoop.yarn.server.nodemanager.LocalDirsHandlerService.access$400(LocalDirsHandlerService.java:50)
        at org.apache.hadoop.yarn.server.nodemanager.LocalDirsHandlerService$MonitoringTimerTask.run(LocalDirsHandlerService.java:122)
        at java.util.TimerThread.mainLoop(Timer.java:555)
        at java.util.TimerThread.run(Timer.java:505)
{noformat}

This disk operation could take longer time than expectation especially in high IO throughput case and we should have fine-grained lock for related operations here. 
The same issue on HDFS get raised and fixed in HDFS-7489, and we probably should have similar fix here.



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