YARN-10796. Capacity Scheduler: dynamic queue cannot scale out properly if its capacity is 0%. Contributed by Peter Bacsko

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

@@ -702,7 +702,8 @@ private void computeNumActiveUsersWithOnlyPendingApps() {
     activeUsersWithOnlyPendingApps = new AtomicInteger(numPendingUsers);
   }
 
-  private Resource computeUserLimit(String userName, Resource clusterResource,
+  @VisibleForTesting
+  Resource computeUserLimit(String userName, Resource clusterResource,
       String nodePartition, SchedulingMode schedulingMode, boolean activeUser) {
     Resource partitionResource = labelManager.getResourceByLabel(nodePartition,
         clusterResource);
@@ -716,6 +717,7 @@ private Resource computeUserLimit(String userName, Resource clusterResource,
      * (which extra resources we are allocating)
      */
     Resource queueCapacity = lQueue.getEffectiveCapacity(nodePartition);
+    Resource originalCapacity = queueCapacity;
 
     /*
      * Assume we have required resource equals to minimumAllocation, this can
@@ -791,16 +793,19 @@ partitionResource, getUsageRatio(nodePartition),
     // IGNORE_PARTITION_EXCLUSIVITY allocation.
     Resource maxUserLimit = Resources.none();
     if (schedulingMode == SchedulingMode.RESPECT_PARTITION_EXCLUSIVITY) {
-      // If user-limit-factor set to -1, we should disabled user limit.
+      if (getUserLimitFactor() == -1 ||
-      if (getUserLimitFactor() != -1) {
+          originalCapacity.equals(Resources.none())) {
-        maxUserLimit = Resources.multiplyAndRoundDown(queueCapacity,
+        // If user-limit-factor set to -1, we should disable user limit.
-            getUserLimitFactor());
+        //
-      } else {
+        // Also prevent incorrect maxUserLimit due to low queueCapacity
+        // Can happen if dynamic queue has capacity = 0%
         maxUserLimit = lQueue.
             getEffectiveMaxCapacityDown(
                 nodePartition, lQueue.getMinimumAllocation());
+      } else {
+        maxUserLimit = Resources.multiplyAndRoundDown(queueCapacity,
+            getUserLimitFactor());
       }
-
     } else if (schedulingMode == SchedulingMode.IGNORE_PARTITION_EXCLUSIVITY) {
       maxUserLimit = partitionResource;
     }
@@ -1131,4 +1136,9 @@ public void updateUserWeights() {
   public int getNumActiveUsersWithOnlyPendingApps() {
     return activeUsersWithOnlyPendingApps.get();
   }
+
+  @VisibleForTesting
+  void setUsageRatio(String label, float usage) {
+    qUsageRatios.usageRatios.put(label, usage);
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestUsersManager.java

@@ -0,0 +1,109 @@
+/**
+ * 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.scheduler.capacity;
+
+import static org.mockito.Mockito.when;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.junit.Assert.assertEquals;
+
+import org.apache.hadoop.yarn.api.records.Resource;
+import org.apache.hadoop.yarn.nodelabels.CommonNodeLabelsManager;
+import org.apache.hadoop.yarn.server.resourcemanager.nodelabels.RMNodeLabelsManager;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics;
+import org.apache.hadoop.yarn.util.resource.DefaultResourceCalculator;
+import org.apache.hadoop.yarn.util.resource.Resources;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class TestUsersManager {
+  private static final Resource CLUSTER_RESOURCE =
+      Resource.newInstance(16384, 16);
+  private static final Resource MINIMUM_ALLOCATION =
+      Resource.newInstance(1024, 1);
+  private static final Resource MAX_RESOURCE_LIMIT =
+      Resource.newInstance(9216, 1);
+  private static final Resource NON_ZERO_CAPACITY =
+      Resource.newInstance(8192, 1);
+  private static final String TEST_USER = "test";
+
+  private UsersManager usersManager;
+
+  @Mock
+  private AutoCreatedLeafQueue lQueue;
+
+  @Mock
+  private RMNodeLabelsManager labelMgr;
+
+  @Mock
+  private QueueMetrics metrics;
+
+  @Mock
+  private CapacitySchedulerContext context;
+
+  @Before
+  public void setup() {
+    usersManager = new UsersManager(metrics,
+        lQueue,
+        labelMgr,
+        context,
+        new DefaultResourceCalculator());
+
+    when(lQueue.getMinimumAllocation()).thenReturn(MINIMUM_ALLOCATION);
+    when(lQueue.getEffectiveMaxCapacityDown(anyString(), any(Resource.class)))
+        .thenReturn(MAX_RESOURCE_LIMIT);
+    when(labelMgr.getResourceByLabel(anyString(), any(Resource.class)))
+        .thenReturn(CLUSTER_RESOURCE);
+    usersManager.setUsageRatio(CommonNodeLabelsManager.NO_LABEL, 0.5f);
+    usersManager.setUserLimit(
+        CapacitySchedulerConfiguration.DEFAULT_USER_LIMIT);
+    usersManager.setUserLimitFactor(
+        CapacitySchedulerConfiguration.DEFAULT_USER_LIMIT_FACTOR);
+  }
+
+  @Test
+  public void testComputeUserLimitWithZeroCapacityQueue() {
+    when(lQueue.getEffectiveCapacity(anyString()))
+        .thenReturn(Resources.none());
+
+    checkLimit(MAX_RESOURCE_LIMIT);
+  }
+
+  @Test
+  public void testComputeUserLimitWithNonZeroCapacityQueue() {
+    when(lQueue.getEffectiveCapacity(anyString()))
+        .thenReturn(NON_ZERO_CAPACITY);
+
+    checkLimit(NON_ZERO_CAPACITY);
+  }
+
+  private void checkLimit(Resource expectedLimit) {
+    Resource limit = usersManager.computeUserLimit(TEST_USER,
+        CLUSTER_RESOURCE,
+        CommonNodeLabelsManager.NO_LABEL,
+        SchedulingMode.RESPECT_PARTITION_EXCLUSIVITY,
+        true);
+
+    assertEquals("User limit", expectedLimit, limit);
+  }
+}