YARN-2113. Add cross-user preemption within CapacityScheduler's leaf-queue. (Sunil G via wangda)

Change-Id: I9b19f69788068be05b3295247cdd7b972f8a573c

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/DefaultResourceCalculator.java

@@ -121,4 +121,9 @@ public boolean fitsIn(Resource cluster,
       Resource smaller, Resource bigger) {
     return smaller.getMemorySize() <= bigger.getMemorySize();
   }
+
+  @Override
+  public boolean isAnyMajorResourceZero(Resource resource) {
+    return resource.getMemorySize() == 0f;
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/DominantResourceCalculator.java

@@ -239,4 +239,9 @@ public boolean fitsIn(Resource cluster,
     return smaller.getMemorySize() <= bigger.getMemorySize()
         && smaller.getVirtualCores() <= bigger.getVirtualCores();
   }
+
+  @Override
+  public boolean isAnyMajorResourceZero(Resource resource) {
+    return resource.getMemorySize() == 0f || resource.getVirtualCores() == 0;
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/ResourceCalculator.java

@@ -204,4 +204,13 @@ public abstract float divide(
    */
   public abstract boolean fitsIn(Resource cluster,
       Resource smaller, Resource bigger);
+
+  /**
+   * Check if resource has any major resource types (which are all NodeManagers
+   * included) a zero value.
+   *
+   * @param resource resource
+   * @return returns true if any resource is zero.
+   */
+  public abstract boolean isAnyMajorResourceZero(Resource resource);
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/Resources.java

@@ -352,4 +352,9 @@ public static Resource componentwiseMax(Resource lhs, Resource rhs) {
     return createResource(Math.max(lhs.getMemorySize(), rhs.getMemorySize()),
         Math.max(lhs.getVirtualCores(), rhs.getVirtualCores()));
   }
+
+  public static boolean isAnyMajorResourceZero(ResourceCalculator rc,
+      Resource resource) {
+    return rc.isAnyMajorResourceZero(resource);
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/CapacitySchedulerPreemptionContext.java

@@ -18,9 +18,11 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity;
 
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
 import org.apache.hadoop.yarn.api.records.ContainerId;
 import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.server.resourcemanager.RMContext;
+import org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity.ProportionalCapacityPreemptionPolicy.IntraQueuePreemptionOrderPolicy;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler;
 import org.apache.hadoop.yarn.util.resource.ResourceCalculator;
 
@@ -63,4 +65,7 @@ TempQueuePerPartition getQueueByPartition(String queueName,
   float getMinimumThresholdForIntraQueuePreemption();
 
   float getMaxAllowableLimitForIntraQueuePreemption();
+
+  @Unstable
+  IntraQueuePreemptionOrderPolicy getIntraQueuePreemptionOrderPolicy();
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/CapacitySchedulerPreemptionUtils.java

@@ -99,7 +99,7 @@ public static void deductPreemptableResourcesBasedSelectedCandidates(
           }
 
           deductPreemptableResourcePerApp(context, tq.totalPartitionResource,
-              tas, res, partition);
+              tas, res);
         }
       }
     }
@@ -108,10 +108,10 @@ public static void deductPreemptableResourcesBasedSelectedCandidates(
   private static void deductPreemptableResourcePerApp(
       CapacitySchedulerPreemptionContext context,
       Resource totalPartitionResource, Collection<TempAppPerPartition> tas,
-      Resource res, String partition) {
+      Resource res) {
     for (TempAppPerPartition ta : tas) {
       ta.deductActuallyToBePreempted(context.getResourceCalculator(),
-          totalPartitionResource, res, partition);
+          totalPartitionResource, res);
     }
   }
 
@@ -157,7 +157,8 @@ public static boolean tryPreemptContainerAndDeductResToObtain(
         && Resources.greaterThan(rc, clusterResource, toObtainByPartition,
             Resources.none())
         && Resources.fitsIn(rc, clusterResource,
-            rmContainer.getAllocatedResource(), totalPreemptionAllowed)) {
+            rmContainer.getAllocatedResource(), totalPreemptionAllowed)
+        && !Resources.isAnyMajorResourceZero(rc, toObtainByPartition)) {
       Resources.subtractFrom(toObtainByPartition,
           rmContainer.getAllocatedResource());
       Resources.subtractFrom(totalPreemptionAllowed,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/FifoIntraQueuePreemptionPlugin.java

@@ -18,11 +18,13 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.PriorityQueue;
 import java.util.Set;
@@ -33,7 +35,9 @@
 import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
 import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity.IntraQueueCandidatesSelector.TAPriorityComparator;
+import org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity.ProportionalCapacityPreemptionPolicy.IntraQueuePreemptionOrderPolicy;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainer;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceUsage;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.LeafQueue;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.SchedulingMode;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerApp;
@@ -60,6 +64,26 @@ public FifoIntraQueuePreemptionPlugin(ResourceCalculator rc,
     this.rc = rc;
   }
 
+  @Override
+  public Collection<FiCaSchedulerApp> getPreemptableApps(String queueName,
+      String partition) {
+    TempQueuePerPartition tq = context.getQueueByPartition(queueName,
+        partition);
+
+    List<FiCaSchedulerApp> apps = new ArrayList<FiCaSchedulerApp>();
+    for (TempAppPerPartition tmpApp : tq.getApps()) {
+      // If a lower priority app was not selected to get preempted, mark such
+      // apps out from preemption candidate selection.
+      if (Resources.equals(tmpApp.getActuallyToBePreempted(),
+          Resources.none())) {
+        continue;
+      }
+
+      apps.add(tmpApp.app);
+    }
+    return apps;
+  }
+
   @Override
   public Map<String, Resource> getResourceDemandFromAppsPerQueue(
       String queueName, String partition) {
@@ -90,7 +114,7 @@ public Map<String, Resource> getResourceDemandFromAppsPerQueue(
 
   @Override
   public void computeAppsIdealAllocation(Resource clusterResource,
-      Resource partitionBasedResource, TempQueuePerPartition tq,
+      TempQueuePerPartition tq,
       Map<ApplicationAttemptId, Set<RMContainer>> selectedCandidates,
       Resource totalPreemptedResourceAllowed,
       Resource queueReassignableResource, float maxAllowablePreemptLimit) {
@@ -113,17 +137,15 @@ public void computeAppsIdealAllocation(Resource clusterResource,
 
     // 3. Create all tempApps for internal calculation and return a list from
     // high priority to low priority order.
-    TAPriorityComparator taComparator = new TAPriorityComparator();
+    PriorityQueue<TempAppPerPartition> orderedByPriority = createTempAppForResCalculation(
-    PriorityQueue<TempAppPerPartition> orderedByPriority =
+        tq, apps, clusterResource, perUserAMUsed);
-        createTempAppForResCalculation(tq.partition, apps, taComparator);
 
     // 4. Calculate idealAssigned per app by checking based on queue's
     // unallocated resource.Also return apps arranged from lower priority to
     // higher priority.
-    TreeSet<TempAppPerPartition> orderedApps =
+    TreeSet<TempAppPerPartition> orderedApps = calculateIdealAssignedResourcePerApp(
-        calculateIdealAssignedResourcePerApp(clusterResource,
+        clusterResource, tq, selectedCandidates, queueReassignableResource,
-            partitionBasedResource, tq, selectedCandidates,
+        orderedByPriority);
-            queueReassignableResource, orderedByPriority, perUserAMUsed);
 
     // 5. A configurable limit that could define an ideal allowable preemption
     // limit. Based on current queue's capacity,defined how much % could become
@@ -146,7 +168,7 @@ public void computeAppsIdealAllocation(Resource clusterResource,
     // 7. From lowest priority app onwards, calculate toBePreempted resource
     // based on demand.
     calculateToBePreemptedResourcePerApp(clusterResource, orderedApps,
-        preemptionLimit);
+        Resources.clone(preemptionLimit));
 
     // Save all apps (low to high) to temp queue for further reference
     tq.addAllApps(orderedApps);
@@ -154,7 +176,8 @@ public void computeAppsIdealAllocation(Resource clusterResource,
     // 8. There are chances that we may preempt for the demand from same
     // priority level, such cases are to be validated out.
     validateOutSameAppPriorityFromDemand(clusterResource,
-        (TreeSet<TempAppPerPartition>) tq.getApps());
+        (TreeSet<TempAppPerPartition>) orderedApps, tq.getUsersPerPartition(),
+        context.getIntraQueuePreemptionOrderPolicy());
 
     if (LOG.isDebugEnabled()) {
       LOG.debug("Queue Name:" + tq.queueName + ", partition:" + tq.partition);
@@ -177,17 +200,17 @@ private void calculateToBePreemptedResourcePerApp(Resource clusterResource,
 
       Resource preemtableFromApp = Resources.subtract(tmpApp.getUsed(),
           tmpApp.idealAssigned);
-      Resources.subtractFrom(preemtableFromApp, tmpApp.selected);
+      Resources.subtractFromNonNegative(preemtableFromApp, tmpApp.selected);
-      Resources.subtractFrom(preemtableFromApp, tmpApp.getAMUsed());
+      Resources.subtractFromNonNegative(preemtableFromApp, tmpApp.getAMUsed());
 
       // Calculate toBePreempted from apps as follows:
       // app.preemptable = min(max(app.used - app.selected - app.ideal, 0),
       // intra_q_preemptable)
       tmpApp.toBePreempted = Resources.min(rc, clusterResource, Resources
           .max(rc, clusterResource, preemtableFromApp, Resources.none()),
-          preemptionLimit);
+          Resources.clone(preemptionLimit));
 
-      preemptionLimit = Resources.subtract(preemptionLimit,
+      preemptionLimit = Resources.subtractFromNonNegative(preemptionLimit,
           tmpApp.toBePreempted);
     }
   }
@@ -222,31 +245,24 @@ private void calculateToBePreemptedResourcePerApp(Resource clusterResource,
    * }
    *  
    * @param clusterResource Cluster Resource
-   * @param partitionBasedResource resource per partition
    * @param tq TempQueue
    * @param selectedCandidates Already Selected preemption candidates
    * @param queueReassignableResource Resource used in a queue
    * @param orderedByPriority List of running apps
-   * @param perUserAMUsed AM used resource
    * @return List of temp apps ordered from low to high priority
    */
   private TreeSet<TempAppPerPartition> calculateIdealAssignedResourcePerApp(
-      Resource clusterResource, Resource partitionBasedResource,
+      Resource clusterResource, TempQueuePerPartition tq,
-      TempQueuePerPartition tq,
       Map<ApplicationAttemptId, Set<RMContainer>> selectedCandidates,
       Resource queueReassignableResource,
-      PriorityQueue<TempAppPerPartition> orderedByPriority,
+      PriorityQueue<TempAppPerPartition> orderedByPriority) {
-      Map<String, Resource> perUserAMUsed) {
 
     Comparator<TempAppPerPartition> reverseComp = Collections
         .reverseOrder(new TAPriorityComparator());
     TreeSet<TempAppPerPartition> orderedApps = new TreeSet<>(reverseComp);
 
-    Map<String, Resource> userIdealAssignedMapping = new HashMap<>();
     String partition = tq.partition;
-
+    Map<String, TempUserPerPartition> usersPerPartition = tq.getUsersPerPartition();
-    Map<String, Resource> preCalculatedUserLimit =
-        new HashMap<String, Resource>();
 
     while (!orderedByPriority.isEmpty()) {
       // Remove app from the next highest remaining priority and process it to
@@ -256,44 +272,19 @@ private TreeSet<TempAppPerPartition> calculateIdealAssignedResourcePerApp(
 
       // Once unallocated resource is 0, we can stop assigning ideal per app.
       if (Resources.lessThanOrEqual(rc, clusterResource,
-          queueReassignableResource, Resources.none())) {
+          queueReassignableResource, Resources.none())
+          || Resources.isAnyMajorResourceZero(rc, queueReassignableResource)) {
         continue;
       }
 
       String userName = tmpApp.app.getUser();
-      Resource userLimitResource = preCalculatedUserLimit.get(userName);
+      TempUserPerPartition tmpUser = usersPerPartition.get(userName);
-
+      Resource userLimitResource = tmpUser.getUserLimit();
-      // Verify whether we already calculated headroom for this user.
+      Resource idealAssignedForUser = tmpUser.idealAssigned;
-      if (userLimitResource == null) {
-        userLimitResource = Resources.clone(
-            tq.leafQueue.getResourceLimitForAllUsers(userName, clusterResource,
-                partition, SchedulingMode.RESPECT_PARTITION_EXCLUSIVITY));
-
-        Resource amUsed = perUserAMUsed.get(userName);
-        if (null == amUsed) {
-          amUsed = Resources.createResource(0, 0);
-        }
-
-        // Real AM used need not have to be considered for user-limit as well.
-        userLimitResource = Resources.subtract(userLimitResource, amUsed);
-        if (LOG.isDebugEnabled()) {
-          LOG.debug("Userlimit for user '" + userName + "' is :"
-              + userLimitResource + ", and amUsed is:" + amUsed);
-        }
-
-        preCalculatedUserLimit.put(userName, userLimitResource);
-      }
-
-      Resource idealAssignedForUser = userIdealAssignedMapping.get(userName);
-
-      if (idealAssignedForUser == null) {
-        idealAssignedForUser = Resources.createResource(0, 0);
-        userIdealAssignedMapping.put(userName, idealAssignedForUser);
-      }
 
       // Calculate total selected container resources from current app.
-      getAlreadySelectedPreemptionCandidatesResource(selectedCandidates,
+      getAlreadySelectedPreemptionCandidatesResource(selectedCandidates, tmpApp,
-          tmpApp, partition);
+          tmpUser, partition);
 
       // For any app, used+pending will give its idealAssigned. However it will
       // be tightly linked to queue's unallocated quota. So lower priority apps
@@ -304,10 +295,11 @@ private TreeSet<TempAppPerPartition> calculateIdealAssignedResourcePerApp(
 
       if (Resources.lessThan(rc, clusterResource, idealAssignedForUser,
           userLimitResource)) {
-        appIdealAssigned = Resources.min(rc, clusterResource, appIdealAssigned,
+        Resource idealAssigned = Resources.min(rc, clusterResource,
+            appIdealAssigned,
             Resources.subtract(userLimitResource, idealAssignedForUser));
         tmpApp.idealAssigned = Resources.clone(Resources.min(rc,
-            clusterResource, queueReassignableResource, appIdealAssigned));
+            clusterResource, queueReassignableResource, idealAssigned));
         Resources.addTo(idealAssignedForUser, tmpApp.idealAssigned);
       } else {
         continue;
@@ -322,7 +314,8 @@ private TreeSet<TempAppPerPartition> calculateIdealAssignedResourcePerApp(
             Resources.subtract(tmpApp.idealAssigned, appUsedExcludedSelected));
       }
 
-      Resources.subtractFrom(queueReassignableResource, tmpApp.idealAssigned);
+      Resources.subtractFromNonNegative(queueReassignableResource,
+          tmpApp.idealAssigned);
     }
 
     return orderedApps;
@@ -334,7 +327,8 @@ private TreeSet<TempAppPerPartition> calculateIdealAssignedResourcePerApp(
    */
   private void getAlreadySelectedPreemptionCandidatesResource(
       Map<ApplicationAttemptId, Set<RMContainer>> selectedCandidates,
-      TempAppPerPartition tmpApp, String partition) {
+      TempAppPerPartition tmpApp, TempUserPerPartition tmpUser,
+      String partition) {
     tmpApp.selected = Resources.createResource(0, 0);
     Set<RMContainer> containers = selectedCandidates
         .get(tmpApp.app.getApplicationAttemptId());
@@ -346,16 +340,23 @@ private void getAlreadySelectedPreemptionCandidatesResource(
     for (RMContainer cont : containers) {
       if (partition.equals(cont.getNodeLabelExpression())) {
         Resources.addTo(tmpApp.selected, cont.getAllocatedResource());
+        Resources.addTo(tmpUser.selected, cont.getAllocatedResource());
       }
     }
   }
 
   private PriorityQueue<TempAppPerPartition> createTempAppForResCalculation(
-      String partition, Collection<FiCaSchedulerApp> apps,
+      TempQueuePerPartition tq, Collection<FiCaSchedulerApp> apps,
-      TAPriorityComparator taComparator) {
+      Resource clusterResource,
+      Map<String, Resource> perUserAMUsed) {
+    TAPriorityComparator taComparator = new TAPriorityComparator();
     PriorityQueue<TempAppPerPartition> orderedByPriority = new PriorityQueue<>(
         100, taComparator);
 
+    String partition = tq.partition;
+    Map<String, TempUserPerPartition> usersPerPartition = tq
+        .getUsersPerPartition();
+
     // have an internal temp app structure to store intermediate data(priority)
     for (FiCaSchedulerApp app : apps) {
 
@@ -387,56 +388,156 @@ private PriorityQueue<TempAppPerPartition> createTempAppForResCalculation(
       tmpApp.idealAssigned = Resources.createResource(0, 0);
 
       orderedByPriority.add(tmpApp);
+
+      // Create a TempUserPerPartition structure to hold more information
+      // regarding each user's entities such as UserLimit etc. This could
+      // be kept in a user to TempUserPerPartition map for further reference.
+      String userName = app.getUser();
+      if (!usersPerPartition.containsKey(userName)) {
+        ResourceUsage userResourceUsage = tq.leafQueue.getUser(userName)
+            .getResourceUsage();
+
+        TempUserPerPartition tmpUser = new TempUserPerPartition(
+            tq.leafQueue.getUser(userName), tq.queueName,
+            Resources.clone(userResourceUsage.getUsed(partition)),
+            Resources.clone(perUserAMUsed.get(userName)),
+            Resources.clone(userResourceUsage.getReserved(partition)),
+            Resources.none());
+
+        Resource userLimitResource = Resources.clone(
+            tq.leafQueue.getResourceLimitForAllUsers(userName, clusterResource,
+                partition, SchedulingMode.RESPECT_PARTITION_EXCLUSIVITY));
+
+        // Real AM used need not have to be considered for user-limit as well.
+        userLimitResource = Resources.subtract(userLimitResource,
+            tmpUser.amUsed);
+        tmpUser.setUserLimit(userLimitResource);
+
+        if (LOG.isDebugEnabled()) {
+          LOG.debug("TempUser:" + tmpUser);
+        }
+
+        tmpUser.idealAssigned = Resources.createResource(0, 0);
+        tq.addUserPerPartition(userName, tmpUser);
+      }
     }
     return orderedByPriority;
   }
 
   /*
    * Fifo+Priority based preemption policy need not have to preempt resources at
-   * same priority level. Such cases will be validated out.
+   * same priority level. Such cases will be validated out. But if the demand is
+   * from an app of different user, force to preempt resources even if apps are
+   * at same priority.
    */
   public void validateOutSameAppPriorityFromDemand(Resource cluster,
-      TreeSet<TempAppPerPartition> appsOrderedfromLowerPriority) {
+      TreeSet<TempAppPerPartition> orderedApps,
+      Map<String, TempUserPerPartition> usersPerPartition,
+      IntraQueuePreemptionOrderPolicy intraQueuePreemptionOrder) {
 
-    TempAppPerPartition[] apps = appsOrderedfromLowerPriority
+    TempAppPerPartition[] apps = orderedApps
-        .toArray(new TempAppPerPartition[appsOrderedfromLowerPriority.size()]);
+        .toArray(new TempAppPerPartition[orderedApps.size()]);
     if (apps.length <= 0) {
       return;
     }
 
-    int lPriority = 0;
+    for (int hPriority = apps.length - 1; hPriority >= 0; hPriority--) {
-    int hPriority = apps.length - 1;
 
-    while (lPriority < hPriority
+      // Check whether high priority app with demand needs resource from other
-        && !apps[lPriority].equals(apps[hPriority])
+      // user.
-        && apps[lPriority].getPriority() < apps[hPriority].getPriority()) {
+      if (Resources.greaterThan(rc, cluster,
-      Resource toPreemptFromOther = apps[hPriority]
+          apps[hPriority].getToBePreemptFromOther(), Resources.none())) {
-          .getToBePreemptFromOther();
-      Resource actuallyToPreempt = apps[lPriority].getActuallyToBePreempted();
-      Resource delta = Resources.subtract(apps[lPriority].toBePreempted,
-          actuallyToPreempt);
 
-      if (Resources.greaterThan(rc, cluster, delta, Resources.none())) {
+        // Given we have a demand from a high priority app, we can do a reverse
-        Resource toPreempt = Resources.min(rc, cluster,
+        // scan from lower priority apps to select resources.
-            toPreemptFromOther, delta);
+        // Since idealAssigned of each app has considered user-limit, this logic
+        // will provide eventual consistency w.r.t user-limit as well.
+        for (int lPriority = 0; lPriority < apps.length; lPriority++) {
 
-        apps[hPriority].setToBePreemptFromOther(
+          // Check whether app with demand needs resource from other user.
-            Resources.subtract(toPreemptFromOther, toPreempt));
+          if (Resources.greaterThan(rc, cluster, apps[lPriority].toBePreempted,
-        apps[lPriority].setActuallyToBePreempted(
+              Resources.none())) {
-            Resources.add(actuallyToPreempt, toPreempt));
-      }
 
-      if (Resources.lessThanOrEqual(rc, cluster,
+            // If apps are of same user, and priority is same, then skip.
-          apps[lPriority].toBePreempted,
+            if ((apps[hPriority].getUser().equals(apps[lPriority].getUser()))
-          apps[lPriority].getActuallyToBePreempted())) {
+                && (apps[lPriority].getPriority() >= apps[hPriority]
-        lPriority++;
+                    .getPriority())) {
-        continue;
+              continue;
-      }
+            }
 
-      if (Resources.equals(apps[hPriority].getToBePreemptFromOther(),
+            if (Resources.lessThanOrEqual(rc, cluster,
-          Resources.none())) {
+                apps[lPriority].toBePreempted,
-        hPriority--;
+                apps[lPriority].getActuallyToBePreempted())
-        continue;
+                || Resources.equals(apps[hPriority].getToBePreemptFromOther(),
+                    Resources.none())) {
+              continue;
+            }
+
+            // Ideally if any application has a higher priority, then it can
+            // force to preempt any lower priority app from any user. However
+            // if admin enforces user-limit over priority, preemption module
+            // will not choose lower priority apps from usre's who are not yet
+            // met its user-limit.
+            TempUserPerPartition tmpUser = usersPerPartition
+                .get(apps[lPriority].getUser());
+            if ((!apps[hPriority].getUser().equals(apps[lPriority].getUser()))
+                && (!tmpUser.isUserLimitReached(rc, cluster))
+                && (intraQueuePreemptionOrder
+                    .equals(IntraQueuePreemptionOrderPolicy.USERLIMIT_FIRST))) {
+              continue;
+            }
+
+            Resource toPreemptFromOther = apps[hPriority]
+                .getToBePreemptFromOther();
+            Resource actuallyToPreempt = apps[lPriority]
+                .getActuallyToBePreempted();
+
+            // A lower priority app could offer more resource to preempt, if
+            // multiple higher priority/under served users needs resources.
+            // After one iteration, we need to ensure that actuallyToPreempt is
+            // subtracted from the resource to preempt.
+            Resource preemptableFromLowerPriorityApp = Resources
+                .subtract(apps[lPriority].toBePreempted, actuallyToPreempt);
+
+            // In case of user-limit preemption, when app's are from different
+            // user and of same priority, we will do user-limit preemption if
+            // there is a demand from under UL quota app.
+            // However this under UL quota app's demand may be more.
+            // Still we should ensure that we are not doing over preemption such
+            // that only a maximum of (user's used - UL quota) could be
+            // preempted.
+            if ((!apps[hPriority].getUser().equals(apps[lPriority].getUser()))
+                && (apps[lPriority].getPriority() == apps[hPriority]
+                    .getPriority())
+                && tmpUser.isUserLimitReached(rc, cluster)) {
+
+              Resource deltaULQuota = Resources
+                  .subtract(tmpUser.getUsedDeductAM(), tmpUser.selected);
+              Resources.subtractFrom(deltaULQuota, tmpUser.getUserLimit());
+
+              if (tmpUser.isPreemptionQuotaForULDeltaDone()) {
+                deltaULQuota = Resources.createResource(0, 0);
+              }
+
+              if (Resources.lessThan(rc, cluster, deltaULQuota,
+                  preemptableFromLowerPriorityApp)) {
+                tmpUser.updatePreemptionQuotaForULDeltaAsDone(true);
+                preemptableFromLowerPriorityApp = deltaULQuota;
+              }
+            }
+
+            if (Resources.greaterThan(rc, cluster,
+                preemptableFromLowerPriorityApp, Resources.none())) {
+              Resource toPreempt = Resources.min(rc, cluster,
+                  toPreemptFromOther, preemptableFromLowerPriorityApp);
+
+              apps[hPriority].setToBePreemptFromOther(
+                  Resources.subtract(toPreemptFromOther, toPreempt));
+              apps[lPriority].setActuallyToBePreempted(
+                  Resources.add(actuallyToPreempt, toPreempt));
+            }
+          }
+        }
       }
     }
   }
@@ -456,6 +557,40 @@ private Resource calculateUsedAMResourcesPerQueue(String partition,
       Resources.addTo(userAMResource, app.getAMResource(partition));
       Resources.addTo(amUsed, app.getAMResource(partition));
     }
+
     return amUsed;
   }
+
+  @Override
+  public boolean skipContainerBasedOnIntraQueuePolicy(FiCaSchedulerApp app,
+      Resource clusterResource, Resource usedResource, RMContainer c) {
+    // Ensure below checks
+    // 1. This check must be done only when preemption order is USERLIMIT_FIRST
+    // 2. By selecting container "c", check whether this user's resource usage
+    // is going below its user-limit.
+    // 3. Used resource of user must be always greater than user-limit to
+    // skip some containers as per this check. If used resource is under user
+    // limit, then these containers of this user has to be preempted as demand
+    // might be due to high priority apps running in same user.
+    String partition = context.getScheduler()
+        .getSchedulerNode(c.getAllocatedNode()).getPartition();
+    TempQueuePerPartition tq = context.getQueueByPartition(app.getQueueName(),
+        partition);
+    TempUserPerPartition tmpUser = tq.getUsersPerPartition().get(app.getUser());
+
+    // Given user is not present, skip the check.
+    if (tmpUser == null) {
+      return false;
+    }
+
+    // For ideal resource computations, user-limit got saved by subtracting am
+    // used resource in TempUser. Hence it has to be added back here for
+    // complete check.
+    Resource userLimit = Resources.add(tmpUser.getUserLimit(), tmpUser.amUsed);
+
+    return Resources.lessThanOrEqual(rc, clusterResource,
+        Resources.subtract(usedResource, c.getAllocatedResource()), userLimit)
+        && context.getIntraQueuePreemptionOrderPolicy()
+            .equals(IntraQueuePreemptionOrderPolicy.USERLIMIT_FIRST);
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/IntraQueueCandidatesSelector.java

@@ -23,6 +23,7 @@
 import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
 import org.apache.hadoop.yarn.api.records.Priority;
 import org.apache.hadoop.yarn.api.records.Resource;
+import org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity.ProportionalCapacityPreemptionPolicy.IntraQueuePreemptionOrderPolicy;
 import org.apache.hadoop.yarn.server.resourcemanager.nodelabels.RMNodeLabelsManager;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainer;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.LeafQueue;
@@ -31,8 +32,9 @@
 
 import java.io.Serializable;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Comparator;
-import java.util.Iterator;
+import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
@@ -51,14 +53,14 @@ static class TAPriorityComparator
         Comparator<TempAppPerPartition> {
 
     @Override
-    public int compare(TempAppPerPartition tq1, TempAppPerPartition tq2) {
+    public int compare(TempAppPerPartition ta1, TempAppPerPartition ta2) {
-      Priority p1 = Priority.newInstance(tq1.getPriority());
+      Priority p1 = Priority.newInstance(ta1.getPriority());
-      Priority p2 = Priority.newInstance(tq2.getPriority());
+      Priority p2 = Priority.newInstance(ta2.getPriority());
 
       if (!p1.equals(p2)) {
         return p1.compareTo(p2);
       }
-      return tq1.getApplicationId().compareTo(tq2.getApplicationId());
+      return ta1.getApplicationId().compareTo(ta2.getApplicationId());
     }
   }
 
@@ -121,17 +123,27 @@ public Map<ApplicationAttemptId, Set<RMContainer>> selectCandidates(
         Map<String, Resource> resToObtainByPartition = fifoPreemptionComputePlugin
             .getResourceDemandFromAppsPerQueue(queueName, partition);
 
-        // 6. Based on the selected resource demand per partition, select
+        // Default preemption iterator considers only FIFO+priority. For
+        // userlimit preemption, its possible that some lower priority apps
+        // needs from high priority app of another user. Hence use apps
+        // ordered by userlimit starvation as well.
+        Collection<FiCaSchedulerApp> apps = fifoPreemptionComputePlugin
+            .getPreemptableApps(queueName, partition);
+
+        // 6. Get user-limit to ensure that we do not preempt resources which
+        // will force user's resource to come under its UL.
+        Map<String, Resource> rollingResourceUsagePerUser = new HashMap<>();
+        initializeUsageAndUserLimitForCompute(clusterResource, partition,
+            leafQueue, rollingResourceUsagePerUser);
+
+        // 7. Based on the selected resource demand per partition, select
         // containers with known policy from inter-queue preemption.
         try {
           leafQueue.getReadLock().lock();
-          Iterator<FiCaSchedulerApp> desc = leafQueue.getOrderingPolicy()
+          for (FiCaSchedulerApp app : apps) {
-              .getPreemptionIterator();
+            preemptFromLeastStarvedApp(leafQueue, app, selectedCandidates,
-          while (desc.hasNext()) {
+                clusterResource, totalPreemptedResourceAllowed,
-            FiCaSchedulerApp app = desc.next();
+                resToObtainByPartition, rollingResourceUsagePerUser);
-            preemptFromLeastStarvedApp(selectedCandidates, clusterResource,
-                totalPreemptedResourceAllowed, resToObtainByPartition,
-                leafQueue, app);
           }
         } finally {
           leafQueue.getReadLock().unlock();
@@ -142,16 +154,30 @@ public Map<ApplicationAttemptId, Set<RMContainer>> selectCandidates(
     return selectedCandidates;
   }
 
-  private void preemptFromLeastStarvedApp(
+  private void initializeUsageAndUserLimitForCompute(Resource clusterResource,
+      String partition, LeafQueue leafQueue,
+      Map<String, Resource> rollingResourceUsagePerUser) {
+    for (String user : leafQueue.getAllUsers()) {
+      // Initialize used resource of a given user for rolling computation.
+      rollingResourceUsagePerUser.put(user, Resources.clone(
+          leafQueue.getUser(user).getResourceUsage().getUsed(partition)));
+      if (LOG.isDebugEnabled()) {
+        LOG.debug("Rolling resource usage for user:" + user + " is : "
+            + rollingResourceUsagePerUser.get(user));
+      }
+    }
+  }
+
+  private void preemptFromLeastStarvedApp(LeafQueue leafQueue,
+      FiCaSchedulerApp app,
       Map<ApplicationAttemptId, Set<RMContainer>> selectedCandidates,
       Resource clusterResource, Resource totalPreemptedResourceAllowed,
-      Map<String, Resource> resToObtainByPartition, LeafQueue leafQueue,
+      Map<String, Resource> resToObtainByPartition,
-      FiCaSchedulerApp app) {
+      Map<String, Resource> rollingResourceUsagePerUser) {
 
     // ToDo: Reuse reservation selector here.
 
-    List<RMContainer> liveContainers = new ArrayList<>(
+    List<RMContainer> liveContainers = new ArrayList<>(app.getLiveContainers());
-        app.getLiveContainers());
     sortContainers(liveContainers);
 
     if (LOG.isDebugEnabled()) {
@@ -160,6 +186,8 @@ private void preemptFromLeastStarvedApp(
               + totalPreemptedResourceAllowed);
     }
 
+    Resource rollingUsedResourcePerUser = rollingResourceUsagePerUser
+        .get(app.getUser());
     for (RMContainer c : liveContainers) {
 
       // if there are no demand, return.
@@ -184,12 +212,34 @@ private void preemptFromLeastStarvedApp(
         continue;
       }
 
-      // Try to preempt this container
+      // If selected container brings down resource usage under its user's
-      CapacitySchedulerPreemptionUtils.tryPreemptContainerAndDeductResToObtain(
+      // UserLimit (or equals to), we must skip such containers.
-          rc, preemptionContext, resToObtainByPartition, c, clusterResource,
+      if (fifoPreemptionComputePlugin.skipContainerBasedOnIntraQueuePolicy(app,
-          selectedCandidates, totalPreemptedResourceAllowed);
+          clusterResource, rollingUsedResourcePerUser, c)) {
-    }
+        if (LOG.isDebugEnabled()) {
+          LOG.debug(
+              "Skipping container: " + c.getContainerId() + " with resource:"
+                  + c.getAllocatedResource() + " as UserLimit for user:"
+                  + app.getUser() + " with resource usage: "
+                  + rollingUsedResourcePerUser + " is going under UL");
+        }
+        break;
+      }
 
+      // Try to preempt this container
+      boolean ret = CapacitySchedulerPreemptionUtils
+          .tryPreemptContainerAndDeductResToObtain(rc, preemptionContext,
+              resToObtainByPartition, c, clusterResource, selectedCandidates,
+              totalPreemptedResourceAllowed);
+
+      // Subtract from respective user's resource usage once a container is
+      // selected for preemption.
+      if (ret && preemptionContext.getIntraQueuePreemptionOrderPolicy()
+          .equals(IntraQueuePreemptionOrderPolicy.USERLIMIT_FIRST)) {
+        Resources.subtractFrom(rollingUsedResourcePerUser,
+            c.getAllocatedResource());
+      }
+    }
   }
 
   private void computeIntraQueuePreemptionDemand(Resource clusterResource,
@@ -205,12 +255,7 @@ private void computeIntraQueuePreemptionDemand(Resource clusterResource,
         continue;
       }
 
-      // 2. Its better to get partition based resource limit earlier before
+      // 2. loop through all queues corresponding to a partition.
-      // starting calculation
-      Resource partitionBasedResource =
-          context.getPartitionResource(partition);
-
-      // 3. loop through all queues corresponding to a partition.
       for (String queueName : queueNames) {
         TempQueuePerPartition tq = context.getQueueByPartition(queueName,
             partition);
@@ -221,23 +266,22 @@ private void computeIntraQueuePreemptionDemand(Resource clusterResource,
           continue;
         }
 
-        // 4. Consider reassignableResource as (used - actuallyToBePreempted).
+        // 3. Consider reassignableResource as (used - actuallyToBePreempted).
         // This provides as upper limit to split apps quota in a queue.
         Resource queueReassignableResource = Resources.subtract(tq.getUsed(),
             tq.getActuallyToBePreempted());
 
-        // 5. Check queue's used capacity. Make sure that the used capacity is
+        // 4. Check queue's used capacity. Make sure that the used capacity is
         // above certain limit to consider for intra queue preemption.
         if (leafQueue.getQueueCapacities().getUsedCapacity(partition) < context
             .getMinimumThresholdForIntraQueuePreemption()) {
           continue;
         }
 
-        // 6. compute the allocation of all apps based on queue's unallocated
+        // 5. compute the allocation of all apps based on queue's unallocated
         // capacity
         fifoPreemptionComputePlugin.computeAppsIdealAllocation(clusterResource,
-            partitionBasedResource, tq, selectedCandidates,
+            tq, selectedCandidates, totalPreemptedResourceAllowed,
-            totalPreemptedResourceAllowed,
             queueReassignableResource,
             context.getMaxAllowableLimitForIntraQueuePreemption());
       }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/IntraQueuePreemptionComputePlugin.java

@@ -18,12 +18,14 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity;
 
+import java.util.Collection;
 import java.util.Map;
 import java.util.Set;
 
 import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
 import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainer;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerApp;
 
 
 interface IntraQueuePreemptionComputePlugin {
@@ -32,8 +34,14 @@ Map<String, Resource> getResourceDemandFromAppsPerQueue(String queueName,
       String partition);
 
   void computeAppsIdealAllocation(Resource clusterResource,
-      Resource partitionBasedResource, TempQueuePerPartition tq,
+      TempQueuePerPartition tq,
       Map<ApplicationAttemptId, Set<RMContainer>> selectedCandidates,
       Resource totalPreemptedResourceAllowed, Resource queueTotalUnassigned,
       float maxAllowablePreemptLimit);
+
+  Collection<FiCaSchedulerApp> getPreemptableApps(String queueName,
+      String partition);
+
+  boolean skipContainerBasedOnIntraQueuePolicy(FiCaSchedulerApp app,
+      Resource clusterResource, Resource usedResource, RMContainer c);
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/ProportionalCapacityPreemptionPolicy.java

@@ -22,6 +22,7 @@
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
 import org.apache.hadoop.yarn.api.records.ContainerId;
@@ -79,6 +80,16 @@
  */
 public class ProportionalCapacityPreemptionPolicy
     implements SchedulingEditPolicy, CapacitySchedulerPreemptionContext {
+
+  /**
+   * IntraQueuePreemptionOrder will be used to define various priority orders
+   * which could be configured by admin.
+   */
+  @Unstable
+  public enum IntraQueuePreemptionOrderPolicy {
+    PRIORITY_FIRST, USERLIMIT_FIRST;
+  }
+
   private static final Log LOG =
     LogFactory.getLog(ProportionalCapacityPreemptionPolicy.class);
 
@@ -95,6 +106,7 @@ public class ProportionalCapacityPreemptionPolicy
 
   private float maxAllowableLimitForIntraQueuePreemption;
   private float minimumThresholdForIntraQueuePreemption;
+  private IntraQueuePreemptionOrderPolicy intraQueuePreemptionOrderPolicy;
 
   // Pointer to other RM components
   private RMContext rmContext;
@@ -190,6 +202,13 @@ public void init(Configuration config, RMContext context,
         CapacitySchedulerConfiguration.
         DEFAULT_INTRAQUEUE_PREEMPTION_MINIMUM_THRESHOLD);
 
+    intraQueuePreemptionOrderPolicy = IntraQueuePreemptionOrderPolicy
+        .valueOf(csConfig
+            .get(
+                CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+                CapacitySchedulerConfiguration.DEFAULT_INTRAQUEUE_PREEMPTION_ORDER_POLICY)
+            .toUpperCase());
+
     rc = scheduler.getResourceCalculator();
     nlm = scheduler.getRMContext().getNodeLabelManager();
 
@@ -242,7 +261,6 @@ public synchronized void editSchedule() {
     }
   }
 
-  @SuppressWarnings("unchecked")
   private void preemptOrkillSelectedContainerAfterWait(
       Map<ApplicationAttemptId, Set<RMContainer>> selectedCandidates,
       long currentTime) {
@@ -652,4 +670,9 @@ public void addPartitionToUnderServedQueues(String queueName,
     }
     underServedQueues.add(queueName);
   }
+
+  @Override
+  public IntraQueuePreemptionOrderPolicy getIntraQueuePreemptionOrderPolicy() {
+    return intraQueuePreemptionOrderPolicy;
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/TempAppPerPartition.java

@@ -91,8 +91,12 @@ public ApplicationId getApplicationId() {
     return applicationId;
   }
 
+  public String getUser() {
+    return this.app.getUser();
+  }
+
   public void deductActuallyToBePreempted(ResourceCalculator resourceCalculator,
-      Resource cluster, Resource toBeDeduct, String partition) {
+      Resource cluster, Resource toBeDeduct) {
     if (Resources.greaterThan(resourceCalculator, cluster,
         getActuallyToBePreempted(), toBeDeduct)) {
       Resources.subtractFrom(getActuallyToBePreempted(), toBeDeduct);

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/TempQueuePerPartition.java

@@ -26,6 +26,8 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Map;
 
 /**
  * Temporary data-structure tracking resource availability, pending resource
@@ -59,6 +61,10 @@ public class TempQueuePerPartition extends AbstractPreemptionEntity {
   int relativePriority = 0;
   TempQueuePerPartition parent = null;
 
+  // This will hold a temp user data structure and will hold userlimit,
+  // idealAssigned, used etc.
+  Map<String, TempUserPerPartition> usersPerPartition = new LinkedHashMap<>();
+
   TempQueuePerPartition(String queueName, Resource current,
       boolean preemptionDisabled, String partition, Resource killable,
       float absCapacity, float absMaxCapacity, Resource totalPartitionResource,
@@ -289,4 +295,12 @@ public Collection<TempAppPerPartition> getApps() {
     return apps;
   }
 
+  public void addUserPerPartition(String userName,
+      TempUserPerPartition tmpUser) {
+    this.usersPerPartition.put(userName, tmpUser);
+  }
+
+  public Map<String, TempUserPerPartition> getUsersPerPartition() {
+    return usersPerPartition;
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/TempUserPerPartition.java

@@ -0,0 +1,88 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity;
+
+import org.apache.hadoop.yarn.api.records.Resource;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.UsersManager.User;
+import org.apache.hadoop.yarn.util.resource.ResourceCalculator;
+import org.apache.hadoop.yarn.util.resource.Resources;
+
+
+/**
+ * Temporary data-structure tracking resource availability, pending resource
+ * need, current utilization for an application.
+ */
+public class TempUserPerPartition extends AbstractPreemptionEntity {
+
+  private final User user;
+  private Resource userLimit;
+  private boolean donePreemptionQuotaForULDelta = false;
+
+  TempUserPerPartition(User user, String queueName, Resource usedPerPartition,
+      Resource amUsedPerPartition, Resource reserved,
+      Resource pendingPerPartition) {
+    super(queueName, usedPerPartition, amUsedPerPartition, reserved,
+        pendingPerPartition);
+    this.user = user;
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append(" NAME: " + getUserName()).append(" CUR: ").append(getUsed())
+        .append(" PEN: ").append(pending).append(" RESERVED: ").append(reserved)
+        .append(" AM_USED: ").append(amUsed).append(" USER_LIMIT: ")
+        .append(getUserLimit()).append(" IDEAL_ASSIGNED: ")
+        .append(idealAssigned).append(" USED_WO_AMUSED: ")
+        .append(getUsedDeductAM()).append(" IDEAL_PREEMPT: ")
+        .append(toBePreempted).append(" ACTUAL_PREEMPT: ")
+        .append(getActuallyToBePreempted()).append("\n");
+
+    return sb.toString();
+  }
+
+  public String getUserName() {
+    return user.getUserName();
+  }
+
+  public Resource getUserLimit() {
+    return userLimit;
+  }
+
+  public void setUserLimit(Resource userLimitResource) {
+    this.userLimit = userLimitResource;
+  }
+
+  public boolean isUserLimitReached(ResourceCalculator rc,
+      Resource clusterResource) {
+    if (Resources.greaterThan(rc, clusterResource, getUsedDeductAM(),
+        userLimit)) {
+      return true;
+    }
+    return false;
+  }
+
+  public boolean isPreemptionQuotaForULDeltaDone() {
+    return this.donePreemptionQuotaForULDelta;
+  }
+
+  public void updatePreemptionQuotaForULDeltaAsDone(boolean done) {
+    this.donePreemptionQuotaForULDelta = done;
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CapacitySchedulerConfiguration.java

@@ -1233,6 +1233,14 @@ public boolean getLazyPreemptionEnabled() {
   public static final float DEFAULT_INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT =
       0.2f;
 
+  /**
+   * For intra-queue preemption, enforce a preemption order such as
+   * "userlimit_first" or "priority_first".
+   */
+  public static final String INTRAQUEUE_PREEMPTION_ORDER_POLICY = PREEMPTION_CONFIG_PREFIX
+      + INTRA_QUEUE_PREEMPTION_CONFIG_PREFIX + "preemption-order-policy";
+  public static final String DEFAULT_INTRAQUEUE_PREEMPTION_ORDER_POLICY = "userlimit_first";
+
   /**
    * Maximum application for a queue to be used when application per queue is
    * not defined.To be consistent with previous version the default value is set

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/LeafQueue.java

@@ -43,12 +43,10 @@
 import org.apache.hadoop.yarn.api.records.QueueState;
 import org.apache.hadoop.yarn.api.records.QueueUserACLInfo;
 import org.apache.hadoop.yarn.api.records.Resource;
-import org.apache.hadoop.yarn.exceptions.InvalidResourceRequestException;
 import org.apache.hadoop.yarn.factories.RecordFactory;
 import org.apache.hadoop.yarn.factory.providers.RecordFactoryProvider;
 import org.apache.hadoop.yarn.nodelabels.CommonNodeLabelsManager;
 import org.apache.hadoop.yarn.security.AccessType;
-import org.apache.hadoop.yarn.server.resourcemanager.RMServerUtils;
 import org.apache.hadoop.yarn.server.resourcemanager.nodelabels.RMNodeLabelsManager;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainer;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainerEventType;
@@ -56,7 +54,6 @@
 
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceLimits;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceUsage;
-import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedContainerChangeRequest;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.*;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.activities.ActivityDiagnosticConstant;
@@ -2022,4 +2019,12 @@ public void stopQueue() {
       writeLock.unlock();
     }
   }
+
+  /**
+   * Get all valid users in this queue.
+   * @return user list
+   */
+  public Set<String> getAllUsers() {
+    return this.getUsersManager().getUsers().keySet();
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/UsersManager.java

@@ -253,6 +253,15 @@ public Resource getUserResourceLimit() {
     public void setUserResourceLimit(Resource userResourceLimit) {
       this.userResourceLimit = userResourceLimit;
     }
+
+    public String getUserName() {
+      return this.userName;
+    }
+
+    @VisibleForTesting
+    public void setResourceUsage(ResourceUsage resourceUsage) {
+      this.userResourceUsage = resourceUsage;
+    }
   } /* End of User class */
 
   /**
@@ -344,7 +353,7 @@ public void userLimitNeedsRecompute() {
   /*
    * Get all users of queue.
    */
-  private Map<String, User> getUsers() {
+  public Map<String, User> getUsers() {
     return users;
   }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/ProportionalCapacityPreemptionPolicyMockFramework.java

@@ -45,6 +45,7 @@
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.QueueCapacities;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.SchedulingMode;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.UsersManager.User;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.preemption.PreemptionManager;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerApp;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerNode;
@@ -96,6 +97,7 @@ public class ProportionalCapacityPreemptionPolicyMockFramework {
   Clock mClock = null;
   CapacitySchedulerConfiguration conf = null;
   CapacityScheduler cs = null;
+  @SuppressWarnings("rawtypes")
   EventHandler<Event> mDisp = null;
   ProportionalCapacityPreemptionPolicy policy = null;
   Resource clusterResource = null;
@@ -247,6 +249,7 @@ public Integer answer(InvocationOnMock invocation) throws Throwable {
         if (containerId == 1) {
           when(rmc.isAMContainer()).thenReturn(true);
           when(app.getAMResource(label)).thenReturn(res);
+          when(app.getAppAMNodePartitionName()).thenReturn(label);
         }
 
         if (reserved) {
@@ -280,6 +283,12 @@ public Integer answer(InvocationOnMock invocation) throws Throwable {
         containerId++;
       }
 
+      // If app has 0 container, and it has only pending, still make sure to
+      // update label.
+      if (repeat == 0) {
+        when(app.getAppAMNodePartitionName()).thenReturn(label);
+      }
+
       // Some more app specific aggregated data can be better filled here.
       when(app.getPriority()).thenReturn(pri);
       when(app.getUser()).thenReturn(userName);
@@ -315,10 +324,15 @@ public Integer answer(InvocationOnMock invocation) throws Throwable {
   private void mockApplications(String appsConfig) {
     int id = 1;
     HashMap<String, HashSet<String>> userMap = new HashMap<String, HashSet<String>>();
+    HashMap<String, HashMap<String, HashMap<String, ResourceUsage>>> userResourceUsagePerLabel = new HashMap<>();
     LeafQueue queue = null;
+    int mulp = -1;
     for (String a : appsConfig.split(";")) {
       String[] strs = a.split("\t");
       String queueName = strs[0];
+      if (mulp <= 0 && strs.length > 2 && strs[2] != null) {
+        mulp = 100 / (new Integer(strs[2]).intValue());
+      }
 
       // get containers
       List<RMContainer> liveContainers = new ArrayList<RMContainer>();
@@ -338,6 +352,7 @@ private void mockApplications(String appsConfig) {
       when(app.getReservedContainers()).thenReturn(reservedContainers);
       when(app.getApplicationAttemptId()).thenReturn(appAttemptId);
       when(app.getApplicationId()).thenReturn(appId);
+      when(app.getQueueName()).thenReturn(queueName);
 
       // add to LeafQueue
       queue = (LeafQueue) nameToCSQueues.get(queueName);
@@ -349,23 +364,71 @@ private void mockApplications(String appsConfig) {
         users = new HashSet<String>();
         userMap.put(queueName, users);
       }
-
       users.add(app.getUser());
+
+      String label = app.getAppAMNodePartitionName();
+
+      // Get label to queue
+      HashMap<String, HashMap<String, ResourceUsage>> userResourceUsagePerQueue = userResourceUsagePerLabel
+          .get(label);
+      if (null == userResourceUsagePerQueue) {
+        userResourceUsagePerQueue = new HashMap<>();
+        userResourceUsagePerLabel.put(label, userResourceUsagePerQueue);
+      }
+
+      // Get queue to user based resource map
+      HashMap<String, ResourceUsage> userResourceUsage = userResourceUsagePerQueue
+          .get(queueName);
+      if (null == userResourceUsage) {
+        userResourceUsage = new HashMap<>();
+        userResourceUsagePerQueue.put(queueName, userResourceUsage);
+      }
+
+      // Get user to its resource usage.
+      ResourceUsage usage = userResourceUsage.get(app.getUser());
+      if (null == usage) {
+        usage = new ResourceUsage();
+        userResourceUsage.put(app.getUser(), usage);
+      }
+
+      usage.incAMUsed(app.getAMResource(label));
+      usage.incUsed(app.getAppAttemptResourceUsage().getUsed(label));
       id++;
     }
 
-    for (String queueName : userMap.keySet()) {
+    for (String label : userResourceUsagePerLabel.keySet()) {
-      queue = (LeafQueue) nameToCSQueues.get(queueName);
+      for (String queueName : userMap.keySet()) {
-      // Currently we have user-limit test support only for default label.
+        queue = (LeafQueue) nameToCSQueues.get(queueName);
-      Resource totResoucePerPartition = partitionToResource.get("");
+        // Currently we have user-limit test support only for default label.
-      Resource capacity = Resources.multiply(totResoucePerPartition,
+        Resource totResoucePerPartition = partitionToResource.get("");
-          queue.getQueueCapacities().getAbsoluteCapacity());
+        Resource capacity = Resources.multiply(totResoucePerPartition,
-      HashSet<String> users = userMap.get(queue.getQueueName());
+            queue.getQueueCapacities().getAbsoluteCapacity());
-      Resource userLimit = Resources.divideAndCeil(rc, capacity, users.size());
+        HashSet<String> users = userMap.get(queue.getQueueName());
-      for (String userName : users) {
+        when(queue.getAllUsers()).thenReturn(users);
-        when(queue.getResourceLimitForAllUsers(eq(userName),
+        Resource userLimit;
-            any(Resource.class), anyString(), any(SchedulingMode.class)))
+        if (mulp > 0) {
-                .thenReturn(userLimit);
+          userLimit = Resources.divideAndCeil(rc, capacity, mulp);
+        } else {
+          userLimit = Resources.divideAndCeil(rc, capacity,
+              users.size());
+        }
+        LOG.debug("Updating user-limit from mock: totResoucePerPartition="
+            + totResoucePerPartition + ", capacity=" + capacity
+            + ", users.size()=" + users.size() + ", userlimit= " + userLimit
+            + ",label= " + label + ",queueName= " + queueName);
+
+        HashMap<String, ResourceUsage> userResourceUsage = userResourceUsagePerLabel
+            .get(label).get(queueName);
+        for (String userName : users) {
+          User user = new User(userName);
+          if (userResourceUsage != null) {
+            user.setResourceUsage(userResourceUsage.get(userName));
+          }
+          when(queue.getUser(eq(userName))).thenReturn(user);
+          when(queue.getResourceLimitForAllUsers(eq(userName),
+              any(Resource.class), anyString(), any(SchedulingMode.class)))
+                  .thenReturn(userLimit);
+        }
       }
     }
   }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/TestProportionalCapacityPreemptionPolicyIntraQueue.java

@@ -62,12 +62,16 @@ public void testSimpleIntraQueuePreemption() throws IOException {
      * Apps which are running at low priority (4) will preempt few of its
      * resources to meet the demand.
      */
+
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
+
     String labelsConfig = "=100,true;";
     String nodesConfig = // n1 has no label
         "n1= res=100";
     String queuesConfig =
         // guaranteed,max,used,pending,reserved
-        "root(=[100 100 80 120 0]);" + // root
+        "root(=[100 100 79 120 0]);" + // root
             "-a(=[11 100 11 50 0]);" + // a
             "-b(=[40 100 38 60 0]);" + // b
             "-c(=[20 100 10 10 0]);" + // c
@@ -304,6 +308,8 @@ public void testLimitPreemptionWithMaxIntraQueuePreemptableLimit()
     conf.setFloat(CapacitySchedulerConfiguration.
         INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
         (float) 0.5);
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;";
     String nodesConfig = // n1 has no label
@@ -357,6 +363,8 @@ public void testLimitPreemptionWithTotalPreemptedResourceAllowed()
     // report "ideal" preempt as 10%. Ensure preemption happens only for 10%
     conf.setFloat(CapacitySchedulerConfiguration.TOTAL_PREEMPTION_PER_ROUND,
         (float) 0.1);
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;";
     String nodesConfig = // n1 has no label
@@ -411,6 +419,8 @@ public void testAlreadySelectedContainerFromInterQueuePreemption()
     conf.setFloat(CapacitySchedulerConfiguration.
         INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
         (float) 0.5);
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;";
     String nodesConfig = // n1 has no label
@@ -418,7 +428,7 @@ public void testAlreadySelectedContainerFromInterQueuePreemption()
     String queuesConfig =
         // guaranteed,max,used,pending,reserved
         "root(=[100 100 95 170 0]);" + // root
-            "-a(=[60 100 70 50 0]);" + // a
+            "-a(=[60 100 70 35 0]);" + // a
             "-b(=[40 100 25 120 0])"; // b
 
     String appsConfig =
@@ -467,6 +477,8 @@ public void testSkipAMContainersInInterQueuePreemption() throws IOException {
     conf.setFloat(CapacitySchedulerConfiguration.
         INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
         (float) 0.5);
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;";
     String nodesConfig = // n1 has no label
@@ -516,6 +528,8 @@ public void testSkipAMContainersInInterQueuePreemptionSingleApp()
      * cycle. Eventhough there are more demand and no other low priority
      * apps are present, still AM contaier need to soared.
      */
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;";
     String nodesConfig = // n1 has no label
@@ -660,6 +674,8 @@ public void testNodePartitionIntraQueuePreemption() throws IOException {
     conf.setFloat(CapacitySchedulerConfiguration.
         INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
         (float) 0.5);
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;" + // default partition
         "x=100,true"; // partition=x
@@ -720,6 +736,8 @@ public void testComplexIntraQueuePreemption() throws IOException {
     conf.setFloat(CapacitySchedulerConfiguration.
         INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
         (float) 0.5);
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;";
     String nodesConfig = // n1 has no label
@@ -840,8 +858,10 @@ public void testIntraQueuePreemptionWithTwoUsers()
     policy.editSchedule();
 
     // Considering user-limit of 50% since only 2 users are there, only preempt
-    // 15 more (5 is already running) eventhough demand is for 30.
+    // 14 more (5 is already running) eventhough demand is for 30. Ideally we
-    verify(mDisp, times(15)).handle(argThat(
+    // must preempt 15. But 15th container will bring user1's usage to 20 which
+    // is same as user-limit. Hence skip 15th container.
+    verify(mDisp, times(14)).handle(argThat(
         new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
             getAppAttemptId(3))));
   }
@@ -869,6 +889,8 @@ public void testComplexNodePartitionIntraQueuePreemption()
     conf.setFloat(CapacitySchedulerConfiguration.
         INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
         (float) 0.5);
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
 
     String labelsConfig = "=100,true;" + // default partition
         "x=100,true"; // partition=x

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/TestProportionalCapacityPreemptionPolicyIntraQueueUserLimit.java

@@ -0,0 +1,899 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity;
+
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerConfiguration;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.mockito.Matchers.argThat;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Test class for IntraQueuePreemption scenarios.
+ */
+public class TestProportionalCapacityPreemptionPolicyIntraQueueUserLimit
+    extends
+      ProportionalCapacityPreemptionPolicyMockFramework {
+  @Before
+  public void setup() {
+    super.setup();
+    conf.setBoolean(
+        CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ENABLED, true);
+    policy = new ProportionalCapacityPreemptionPolicy(rmContext, cs, mClock);
+  }
+
+  @Test
+  public void testSimpleIntraQueuePreemptionWithTwoUsers()
+      throws IOException {
+    /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     * Preconditions:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 100  | 0       |
+     *   | app2 | user2 | 1        | 0    | 30      |
+     *   +--------------+----------+------+---------+
+     * Hence in queueA of 100, each user has a quota of 50. app1 of high priority
+     * has a demand of 0 and its already using 100. app2 from user2 has a demand
+     * of 30, and UL is 50. 30 would be preempted from app1.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 30 0]);" + // root
+            "-a(=[100 100 100 30 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,1,n1,,100,false,0,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,0,false,30,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 needs more resource and its well under its user-limit. Hence preempt
+    // resources from app1.
+    verify(mDisp, times(30)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+  }
+
+  @Test
+  public void testNoIntraQueuePreemptionWithSingleUser()
+      throws IOException {
+    /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 100  | 0       |
+     *   | app2 | user1 | 1        | 0    | 30      |
+     *   +--------------+----------+------+---------+
+     * Given single user, lower priority/late submitted apps has to
+     * wait.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 30 0]);" + // root
+            "-a(=[100 100 100 30 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,1,n1,,100,false,0,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,0,false,30,user1)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 needs more resource. Since app1,2 are from same user, there wont be
+    // any preemption.
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+  }
+
+  @Test
+  public void testNoIntraQueuePreemptionWithTwoUserUnderUserLimit()
+      throws IOException {
+    /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 50   | 0       |
+     *   | app2 | user2 | 1        | 30   | 30      |
+     *   +--------------+----------+------+---------+
+     * Hence in queueA of 100, each user has a quota of 50. app1 of high priority
+     * has a demand of 0 and its already using 50. app2 from user2 has a demand
+     * of 30, and UL is 50. Since app1 is under UL, there should not be any
+     * preemption.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 80 30 0]);" + // root
+            "-a(=[100 100 80 30 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,1,n1,,50,false,0,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,30,false,30,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 needs more resource. Since app1,2 are from same user, there wont be
+    // any preemption.
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+  }
+
+  @Test
+  public void testSimpleIntraQueuePreemptionWithTwoUsersWithAppPriority()
+      throws IOException {
+    /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 2        | 100  | 0       |
+     *   | app2 | user2 | 1        | 0    | 30      |
+     *   +--------------+----------+------+---------+
+     * Hence in queueA of 100, each user has a quota of 50. app1 of high priority
+     * has a demand of 0 and its already using 100. app2 from user2 has a demand
+     * of 30, and UL is 50. 30 would be preempted from app1.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 30 0]);" + // root
+            "-a(=[100 100 100 30 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(2,1,n1,,100,false,0,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,0,false,30,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 needs more resource and its well under its user-limit. Hence preempt
+    // resources from app1 even though its priority is more than app2.
+    verify(mDisp, times(30)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+  }
+
+  @Test
+  public void testIntraQueuePreemptionOfUserLimitWithMultipleApps()
+      throws IOException {
+    /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 30   | 30      |
+     *   | app2 | user2 | 1        | 20   | 20      |
+     *   | app3 | user1 | 1        | 30   | 30      |
+     *   | app4 | user2 | 1        | 0    | 10      |
+     *   +--------------+----------+------+---------+
+     * Hence in queueA of 100, each user has a quota of 50. Now have multiple
+     * apps and check for preemption across apps.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 80 90 0]);" + // root
+            "-a(=[100 100 80 90 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,1,n1,,30,false,30,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,20,false,20,user2);" +
+            "a\t" // app3 in a
+            + "(1,1,n1,,30,false,30,user1);" +
+            "a\t" // app4 in a
+            + "(1,1,n1,,0,false,10,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2/app4 needs more resource and its well under its user-limit. Hence
+    // preempt resources from app3 (compare to app1, app3 has low priority).
+    verify(mDisp, times(9)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(3))));
+  }
+
+  @Test
+  public void testNoPreemptionOfUserLimitWithMultipleAppsAndSameUser()
+      throws IOException {
+    /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 30   | 30      |
+     *   | app2 | user1 | 1        | 20   | 20      |
+     *   | app3 | user1 | 1        | 30   | 30      |
+     *   | app4 | user1 | 1        | 0    | 10      |
+     *   +--------------+----------+------+---------+
+     * Hence in queueA of 100, each user has a quota of 50. Now have multiple
+     * apps and check for preemption across apps.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 80 90 0]);" + // root
+            "-a(=[100 100 80 90 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,1,n1,,30,false,20,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,20,false,20,user1);" +
+            "a\t" // app3 in a
+            + "(1,1,n1,,30,false,30,user1);" +
+            "a\t" // app4 in a
+            + "(1,1,n1,,0,false,10,user1)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2/app4 needs more resource and its well under its user-limit. Hence
+    // preempt resources from app3 (compare to app1, app3 has low priority).
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(2))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(3))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(4))));
+  }
+
+  @Test
+  public void testIntraQueuePreemptionOfUserLimitWitAppsOfDifferentPriority()
+      throws IOException {
+    /**
+     * Queue structure is:
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 3        | 30   | 30      |
+     *   | app2 | user2 | 1        | 20   | 20      |
+     *   | app3 | user1 | 4        | 30   | 0       |
+     *   | app4 | user2 | 1        | 0    | 10      |
+     *   +--------------+----------+------+---------+
+     * Hence in queueA of 100, each user has a quota of 50. Now have multiple
+     * apps and check for preemption across apps.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(
+        CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 80 60 0]);" + // root
+            "-a(=[100 100 80 60 0])"; // b
+
+    String appsConfig =
+        // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(3,1,n1,,30,false,30,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,20,false,20,user2);" + "a\t" // app3 in a
+            + "(4,1,n1,,30,false,0,user1);" + "a\t" // app4 in a
+            + "(1,1,n1,,0,false,10,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2/app4 needs more resource and its well under its user-limit. Hence
+    // preempt resources from app1 (compare to app3, app1 has low priority).
+    verify(mDisp, times(9)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+  }
+
+  @Test
+  public void testIntraQueuePreemptionOfUserLimitInTwoQueues()
+      throws IOException {
+    /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *      /   \
+     *     a     b
+     * </pre>
+     *
+     * Guaranteed resource of a/b are 40:60 Total cluster resource = 100
+     * maxIntraQueuePreemptableLimit by default is 50%. This test is to verify
+     * that intra-queue preemption could occur in two queues when user-limit
+     * irreuglarity is present in queue.
+     */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+            INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 90 80 0]);" + // root
+            "-a(=[60 100 55 60 0]);" + // a
+            "-b(=[40 100 35 20 0])"; // b
+
+    String appsConfig =
+        // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(3,1,n1,,20,false,30,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,20,false,20,user2);" +
+            "a\t" // app3 in a
+            + "(4,1,n1,,15,false,0,user1);" +
+            "a\t" // app4 in a
+            + "(1,1,n1,,0,false,10,user2);" +
+            "b\t" // app5 in b
+            + "(3,1,n1,,25,false,10,user1);" +
+            "b\t" // app6 in b
+            + "(1,1,n1,,10,false,10,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2/app4 needs more resource and its well under its user-limit. Hence
+    // preempt resources from app1 (compare to app3, app1 has low priority).
+    verify(mDisp, times(4)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(4)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(5))));
+  }
+
+  @Test
+  public void testIntraQueuePreemptionWithTwoRequestingUsers()
+      throws IOException {
+    /**
+    * Queue structure is:
+    *
+    * <pre>
+    *       root
+    *        |
+    *        a
+    * </pre>
+    *
+    * Scenario:
+    *   Queue total resources: 100
+    *   Minimum user limit percent: 50%
+    *   +--------------+----------+------+---------+
+    *   | APP  | USER  | PRIORITY | USED | PENDING |
+    *   +--------------+----------+------+---------+
+    *   | app1 | user1 | 1        | 60   | 10      |
+    *   | app2 | user2 | 1        | 40   | 10      |
+    *   +--------------+----------+------+---------+
+    * Hence in queueA of 100, each user has a quota of 50. Now have multiple
+    * apps and check for preemption across apps.
+    */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 20 0]);" + // root
+            "-a(=[100 100 100 20 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,1,n1,,60,false,10,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,40,false,10,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 needs more resource and its well under its user-limit. Hence preempt
+    // resources from app1.
+    verify(mDisp, times(9)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(2))));
+  }
+
+  @Test
+  public void testNoIntraQueuePreemptionIfBelowUserLimitAndLowPriorityExtraUsers()
+      throws IOException {
+     /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     * Preconditions:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 50   | 0       |
+     *   | app2 | user2 | 1        | 50   | 0       |
+     *   | app3 | user3 | 0        | 0    | 10      |
+     *   +--------------+----------+------+---------+
+     * This scenario should never preempt from either user1 or user2
+     */
+
+    // Set max preemption per round to 50% (this is different from minimum user
+    // limit percent).
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.7);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 10 0]);" + // root
+            "-a(=[100 100 100 10 0])"; // a
+
+    String appsConfig =
+    // queueName\t\
+    //     (priority,resource,host,label,#repeat,reserved,pending,user)\tMULP;
+        "a\t(1,1,n1,,50,false,0,user1)\t50;" + // app1, user1
+        "a\t(1,1,n1,,50,false,0,user2)\t50;" + // app2, user2
+        "a\t(0,1,n1,,0,false,10,user3)\t50";   // app3, user3
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2/app4 needs more resource and its well under its user-limit. Hence
+    // preempt resources from app1 (compare to app3, app1 has low priority).
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(2))));
+  }
+
+  @Test
+  public void testNoIntraQueuePreemptionIfBelowUserLimitAndSamePriorityExtraUsers()
+      throws IOException {
+     /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     * Preconditions:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 50   | 0       |
+     *   | app2 | user2 | 1        | 50   | 0       |
+     *   | app3 | user3 | 1        | 0    | 10      |
+     *   +--------------+----------+------+---------+
+     * This scenario should never preempt from either user1 or user2
+     */
+
+    // Set max preemption per round to 50% (this is different from minimum user
+    // limit percent).
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.7);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 10 0]);" + // root
+            "-a(=[100 100 100 10 0])"; // a
+
+    String appsConfig =
+    // queueName\t\
+    //     (priority,resource,host,label,#repeat,reserved,pending,user)\tMULP;
+        "a\t(1,1,n1,,50,false,0,user1)\t50;" + // app1, user1
+        "a\t(1,1,n1,,50,false,0,user2)\t50;" + // app2, user2
+        "a\t(1,1,n1,,0,false,10,user3)\t50";   // app3, user3
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2/app4 needs more resource and its well under its user-limit. Hence
+    // preempt resources from app1 (compare to app3, app1 has low priority).
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(2))));
+  }
+
+  @Test
+  public void testNoIntraQueuePreemptionIfBelowUserLimitAndHighPriorityExtraUsers()
+      throws IOException {
+     /**
+     * Queue structure is:
+     *
+     * <pre>
+     *       root
+     *        |
+     *        a
+     * </pre>
+     *
+     * Scenario:
+     * Preconditions:
+     *   Queue total resources: 100
+     *   Minimum user limit percent: 50%
+     *   +--------------+----------+------+---------+
+     *   | APP  | USER  | PRIORITY | USED | PENDING |
+     *   +--------------+----------+------+---------+
+     *   | app1 | user1 | 1        | 50   | 0       |
+     *   | app2 | user2 | 1        | 50   | 0       |
+     *   | app3 | user3 | 5        | 0    | 10      |
+     *   +--------------+----------+------+---------+
+     * This scenario should never preempt from either user1 or user2
+     */
+
+    // Set max preemption per round to 50% (this is different from minimum user
+    // limit percent).
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.7);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 10 0]);" + // root
+            "-a(=[100 100 100 10 0])"; // a
+
+    String appsConfig =
+    // queueName\t\
+    //     (priority,resource,host,label,#repeat,reserved,pending,user)\tMULP;
+        "a\t(1,1,n1,,50,false,0,user1)\t50;" + // app1, user1
+        "a\t(1,1,n1,,50,false,0,user2)\t50;" + // app2, user2
+        "a\t(5,1,n1,,0,false,10,user3)\t50";   // app3, user3
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2/app4 needs more resource and its well under its user-limit. Hence
+    // preempt resources from app1 (compare to app3, app1 has low priority).
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(2))));
+  }
+
+  @Test
+  public void testNoIntraQueuePreemptionWithUserLimitDeadzone()
+      throws IOException {
+    /**
+    * Queue structure is:
+    *
+    * <pre>
+    *       root
+    *        |
+    *        a
+    * </pre>
+    *
+    * Scenario:
+    *   Queue total resources: 100
+    *   Minimum user limit percent: 50%
+    *   +--------------+----------+------+---------+
+    *   | APP  | USER  | PRIORITY | USED | PENDING |
+    *   +--------------+----------+------+---------+
+    *   | app1 | user1 | 1        | 60   | 10      |
+    *   | app2 | user2 | 1        | 40   | 10      |
+    *   +--------------+----------+------+---------+
+    * Hence in queueA of 100, each user has a quota of 50. Now have multiple
+    * apps and check for preemption across apps but also ensure that user's
+    * usage not coming under its user-limit.
+    */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 20 0]);" + // root
+            "-a(=[100 100 100 20 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,3,n1,,20,false,10,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,40,false,10,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 needs more resource and its well under its user-limit. Hence preempt
+    // 3 resources (9GB) from app1. We will not preempt last container as it may
+    // pull user's usage under its user-limit.
+    verify(mDisp, times(3)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(2))));
+  }
+
+  @Test
+  public void testIntraQueuePreemptionWithUserLimitDeadzoneAndPriority()
+      throws IOException {
+    /**
+    * Queue structure is:
+    *
+    * <pre>
+    *       root
+    *        |
+    *        a
+    * </pre>
+    *
+    * Scenario:
+    *   Queue total resources: 100
+    *   Minimum user limit percent: 50%
+    *   +--------------+----------+------+---------+
+    *   | APP  | USER  | PRIORITY | USED | PENDING |
+    *   +--------------+----------+------+---------+
+    *   | app1 | user1 | 1        | 60   | 10      |
+    *   | app2 | user2 | 1        | 40   | 10      |
+    *   +--------------+----------+------+---------+
+    * Hence in queueA of 100, each user has a quota of 50. Now have multiple
+    * apps and check for preemption across apps but also ensure that user's
+    * usage not coming under its user-limit.
+    */
+
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100 100 100 20 0]);" + // root
+            "-a(=[100 100 100 20 0])"; // a
+
+    String appsConfig =
+    // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,3,n1,,20,false,10,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(2,1,n1,,0,false,10,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,40,false,20,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 needs more resource and its well under its user-limit. Hence preempt
+    // 3 resources (9GB) from app1. We will not preempt last container as it may
+    // pull user's usage under its user-limit.
+    verify(mDisp, times(3)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+    verify(mDisp, times(0)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(2))));
+
+    // After first round, 3 containers were preempted from app1 and resource
+    // distribution will be like below.
+    appsConfig =
+        // queueName\t(priority,resource,host,expression,#repeat,reserved,pending)
+        "a\t" // app1 in a
+            + "(1,3,n1,,17,false,10,user1);" + // app1 a
+            "a\t" // app2 in a
+            + "(2,1,n1,,0,false,10,user1);" + // app2 a
+            "a\t" // app2 in a
+            + "(1,1,n1,,49,false,11,user2)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // app2 has priority demand within same user 'user1'. However user1's used
+    // is alredy under UL. Hence no preemption. We will still get 3 container
+    // while asserting as it was aleady selected in earlier round.
+    verify(mDisp, times(3)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(1))));
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/TestProportionalCapacityPreemptionPolicyIntraQueueWithDRF.java

@@ -0,0 +1,178 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.monitor.capacity;
+
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerConfiguration;
+import org.apache.hadoop.yarn.util.resource.DominantResourceCalculator;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.mockito.Matchers.argThat;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * Test class for IntraQueuePreemption scenarios.
+ */
+public class TestProportionalCapacityPreemptionPolicyIntraQueueWithDRF
+    extends
+      ProportionalCapacityPreemptionPolicyMockFramework {
+  @Before
+  public void setup() {
+    super.setup();
+    conf.setBoolean(
+        CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ENABLED, true);
+    rc = new DominantResourceCalculator();
+    when(cs.getResourceCalculator()).thenReturn(rc);
+    policy = new ProportionalCapacityPreemptionPolicy(rmContext, cs, mClock);
+  }
+
+  @Test
+  public void testSimpleIntraQueuePreemptionWithVCoreResource()
+      throws IOException {
+    /**
+     * The simplest test preemption, Queue structure is:
+     *
+     * <pre>
+     *       root
+     *     /  | | \
+     *    a  b  c  d
+     * </pre>
+     *
+     * Guaranteed resource of a/b/c/d are 10:40:20:30 Total cluster resource =
+     * 100 Scenario: Queue B has few running apps and two high priority apps
+     * have demand. Apps which are running at low priority (4) will preempt few
+     * of its resources to meet the demand.
+     */
+
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
+
+    String labelsConfig = "=100:200,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100:200";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100:50 100:50 80:40 120:60 0]);" + // root
+            "-a(=[10:5 100:50 10:5 50:25 0]);" + // a
+            "-b(=[40:20 100:50 40:20 60:30 0]);" + // b
+            "-c(=[20:10 100:50 10:5 10:5 0]);" + // c
+            "-d(=[30:15 100:50 20:10 0 0])"; // d
+
+    String appsConfig =
+        // queueName\t(priority,resource,host,expression,#repeat,reserved,
+        // pending)
+        "a\t" // app1 in a
+            + "(1,1:1,n1,,5,false,25:25);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1:1,n1,,5,false,25:25);" + // app2 a
+            "b\t" // app3 in b
+            + "(4,1:1,n1,,36,false,20:20);" + // app3 b
+            "b\t" // app4 in b
+            + "(4,1:1,n1,,2,false,10:10);" + // app4 b
+            "b\t" // app4 in b
+            + "(5,1:1,n1,,1,false,10:10);" + // app5 b
+            "b\t" // app4 in b
+            + "(6,1:1,n1,,1,false,10:10);" + // app6 in b
+            "c\t" // app1 in a
+            + "(1,1:1,n1,,10,false,10:10);" + "d\t" // app7 in c
+            + "(1,1:1,n1,,20,false,0)";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // For queue B, app3 and app4 were of lower priority. Hence take 8
+    // containers from them by hitting the intraQueuePreemptionDemand of 20%.
+    verify(mDisp, times(1)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(4))));
+    verify(mDisp, times(7)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(3))));
+  }
+
+  @Test
+  public void testIntraQueuePreemptionWithDominantVCoreResource()
+      throws IOException {
+    /**
+     * The simplest test preemption, Queue structure is:
+     *
+     * <pre>
+     *     root
+     *     /  \
+     *    a    b
+     * </pre>
+     *
+     * Guaranteed resource of a/b are 40:60 Total cluster resource = 100
+     * Scenario: Queue B has few running apps and two high priority apps have
+     * demand. Apps which are running at low priority (4) will preempt few of
+     * its resources to meet the demand.
+     */
+
+    conf.set(CapacitySchedulerConfiguration.INTRAQUEUE_PREEMPTION_ORDER_POLICY,
+        "priority_first");
+    // Set max preemption limit as 50%.
+    conf.setFloat(CapacitySchedulerConfiguration.
+        INTRAQUEUE_PREEMPTION_MAX_ALLOWABLE_LIMIT,
+        (float) 0.5);
+
+    String labelsConfig = "=100:200,true;";
+    String nodesConfig = // n1 has no label
+        "n1= res=100:200";
+    String queuesConfig =
+        // guaranteed,max,used,pending,reserved
+        "root(=[100:50 100:50 50:40 110:60 0]);" + // root
+            "-a(=[40:20 100:50 9:9 50:30 0]);" + // a
+            "-b(=[60:30 100:50 40:30 60:30 0]);"; // b
+
+    String appsConfig =
+        // queueName\t(priority,resource,host,expression,#repeat,reserved,
+        // pending)
+        "a\t" // app1 in a
+            + "(1,2:1,n1,,4,false,25:25);" + // app1 a
+            "a\t" // app2 in a
+            + "(1,1:3,n1,,2,false,25:25);" + // app2 a
+            "b\t" // app3 in b
+            + "(4,2:1,n1,,10,false,20:20);" + // app3 b
+            "b\t" // app4 in b
+            + "(4,1:2,n1,,5,false,10:10);" + // app4 b
+            "b\t" // app5 in b
+            + "(5,1:1,n1,,5,false,30:20);" + // app5 b
+            "b\t" // app6 in b
+            + "(6,2:1,n1,,5,false,30:20);";
+
+    buildEnv(labelsConfig, nodesConfig, queuesConfig, appsConfig);
+    policy.editSchedule();
+
+    // For queue B, app3 and app4 were of lower priority. Hence take 4
+    // containers.
+    verify(mDisp, times(9)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(3))));
+    verify(mDisp, times(4)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(4))));
+    verify(mDisp, times(4)).handle(argThat(
+        new TestProportionalCapacityPreemptionPolicy.IsPreemptionRequestFor(
+            getAppAttemptId(5))));
+  }
+}