[YARN-7591] NPE in async-scheduling mode of CapacityScheduler

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha4, 2.9.1
• Fix Version/s: 3.0.0, 2.9.1
• Component/s: capacityscheduler
• Target Version/s: 2.9.1
• Hadoop Flags: Reviewed
• Assignee: Tao Yang
• Reporter: Tao Yang
• Created: 01/Dec/17 07:05
• Updated: 05/Feb/18 02:22
• Resolved: 08/Dec/17 23:24

Description

Currently in async-scheduling mode of CapacityScheduler, NPE may be raised in special scenarios as below.
(1) The user should be removed after its last application finished, NPE may be raised if getting something from user object without the null check in async-scheduling threads.
(2) NPE may be raised when trying fulfill reservation for a finished application in CapacityScheduler#allocateContainerOnSingleNode.

    RMContainer reservedContainer = node.getReservedContainer();
    if (reservedContainer != null) {
      FiCaSchedulerApp reservedApplication = getCurrentAttemptForContainer(
          reservedContainer.getContainerId());

      // NPE here: reservedApplication could be null after this application finished
      // Try to fulfill the reservation
      LOG.info(
          "Trying to fulfill reservation for application " + reservedApplication
              .getApplicationId() + " on node: " + node.getNodeID());

(3) If proposal1 (allocate containerX on node1) and proposal2 (reserve containerY on node1) were generated by different async-scheduling threads around the same time and proposal2 was submitted in front of proposal1, NPE is raised when trying to submit proposal2 in FiCaSchedulerApp#commonCheckContainerAllocation.

    if (reservedContainerOnNode != null) {
      // NPE here: allocation.getAllocateFromReservedContainer() should be null for proposal2 in this case
      RMContainer fromReservedContainer =
          allocation.getAllocateFromReservedContainer().getRmContainer();

      if (fromReservedContainer != reservedContainerOnNode) {
        if (LOG.isDebugEnabled()) {
          LOG.debug(
              "Try to allocate from a non-existed reserved container");
        }
        return false;
      }
    }

Issue Links

• is duplicated by: YARN-7880 CapacityScheduler$ResourceCommitterService throws NPE when running sls