[jira] [Created] (YARN-11785) Race condition in QueueMetrics due to non-thread-safe HashMap causes MetricsException

["Tao Yang (Jira)" <ji...@apache.org>]

Tao Yang created YARN-11785:
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             Summary: Race condition in QueueMetrics due to non-thread-safe HashMap causes MetricsException
                 Key: YARN-11785
                 URL: https://issues.apache.org/jira/browse/YARN-11785
             Project: Hadoop YARN
          Issue Type: Bug
          Components: capacityscheduler
    Affects Versions: 3.4.1, 3.3.6, 3.2.4
            Reporter: Tao Yang
            Assignee: Tao Yang


In high-concurrency scenarios, the async-scheduling thread may fail to retrieve an existing PartitionQueueMetric from QueueMetrics#QUEUE_METRICS (returns null), then attempt to re-register the same queue name. This triggers a MetricsException ("Duplicate metric name") and causes the async-scheduling thread to exit unexpectedly. Below is the error stack trace:
{code:java}
ERROR org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Received RMFatalEvent of type CRITICAL_THREAD_CRASH, caused by a critical thread, Thread-12, that exited unexpectedly: org.apache.hadoop.metrics2.MetricsException: Metrics source PartitionQueueMetrics,partition=,q0=root,q1=xxx already exists!
    at org.apache.hadoop.metrics2.lib.DefaultMetricsSystem.newSourceName(DefaultMetricsSystem.java:152)
    at org.apache.hadoop.metrics2.lib.DefaultMetricsSystem.sourceName(DefaultMetricsSystem.java:125)
    at org.apache.hadoop.metrics2.impl.MetricsSystemImpl.register(MetricsSystemImpl.java:229)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics.getPartitionQueueMetrics(QueueMetrics.java:286)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics.setAvailableResourcesToUser(QueueMetrics.java:529)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.LeafQueue.computeUserLimitAndSetHeadroom(LeafQueue.java:1490)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.LeafQueue.assignContainers(LeafQueue.java:1146)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.assignContainersToChildQueues(ParentQueue.java:803)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.assignContainers(ParentQueue.java:623)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.assignContainersToChildQueues(ParentQueue.java:803)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.assignContainers(ParentQueue.java:623)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateOrReserveNewContainers(CapacityScheduler.java:1697)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateContainerOnSingleNode(CapacityScheduler.java:1632)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateContainersToNode(CapacityScheduler.java:1787)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateContainersToNode(CapacityScheduler.java:1536)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.schedule(CapacityScheduler.java:606)
    at org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler$AsyncScheduleThread.run(CapacityScheduler.java:653) {code}
The root cause is that QUEUE_METRICS field is implemented with HashMap, which is not thread-safe. Concurrent put and get operations can lead to visibility issue. This issue can be fixed by ensuring thread-safe access via ConcurrentHashMap for QUEUE_METRICS field.



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