YARN-2628. Capacity scheduler with DominantResourceCalculator carries out reservation even though slots are free. Contributed by Varun Vasudev

(cherry picked from commit 054f285526)

hadoop-yarn-project/CHANGES.txt

@@ -497,6 +497,9 @@ Release 2.6.0 - UNRELEASED
     YARN-2527. Fixed the potential NPE in ApplicationACLsManager and added test
     cases for it. (Benoy Antony via zjshen)
 
+    YARN-2628. Capacity scheduler with DominantResourceCalculator carries out
+    reservation even though slots are free. (Varun Vasudev via jianhe)
+
 Release 2.5.1 - 2014-09-05
 
   INCOMPATIBLE CHANGES

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

@@ -941,8 +941,8 @@ public class CapacityScheduler extends
 
     // Try to schedule more if there are no reservations to fulfill
     if (node.getReservedContainer() == null) {
-      if (Resources.greaterThanOrEqual(calculator, getClusterResource(),
+      if (calculator.computeAvailableContainers(node.getAvailableResource(),
-          node.getAvailableResource(), minimumAllocation)) {
+        minimumAllocation) > 0) {
         if (LOG.isDebugEnabled()) {
           LOG.debug("Trying to schedule on node: " + node.getNodeName() +
               ", available: " + node.getAvailableResource());

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

@@ -64,6 +64,7 @@ import org.apache.hadoop.yarn.api.records.QueueUserACLInfo;
 import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.api.records.ResourceOption;
 import org.apache.hadoop.yarn.api.records.ResourceRequest;
+import org.apache.hadoop.yarn.api.records.ApplicationResourceUsageReport;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.event.AsyncDispatcher;
 import org.apache.hadoop.yarn.exceptions.YarnException;
@@ -115,6 +116,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.CapacitySchedule
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.CapacitySchedulerQueueInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.CapacitySchedulerQueueInfoList;
 import org.apache.hadoop.yarn.server.utils.BuilderUtils;
+import org.apache.hadoop.yarn.util.resource.DominantResourceCalculator;
 import org.apache.hadoop.yarn.util.resource.Resources;
 import org.junit.After;
 import org.junit.Assert;
@@ -1995,4 +1997,66 @@ public class TestCapacityScheduler {
     rm.stop();
   }
 
+  // Test to ensure that we don't carry out reservation on nodes
+  // that have no CPU available when using the DominantResourceCalculator
+  @Test(timeout = 30000)
+  public void testAppReservationWithDominantResourceCalculator() throws Exception {
+    CapacitySchedulerConfiguration csconf =
+        new CapacitySchedulerConfiguration();
+    csconf.setResourceComparator(DominantResourceCalculator.class);
+
+    YarnConfiguration conf = new YarnConfiguration(csconf);
+    conf.setClass(YarnConfiguration.RM_SCHEDULER, CapacityScheduler.class,
+      ResourceScheduler.class);
+
+    MockRM rm = new MockRM(conf);
+    rm.start();
+
+    MockNM nm1 = rm.registerNode("127.0.0.1:1234", 10 * GB, 1);
+
+    // register extra nodes to bump up cluster resource
+    MockNM nm2 = rm.registerNode("127.0.0.1:1235", 10 * GB, 4);
+    rm.registerNode("127.0.0.1:1236", 10 * GB, 4);
+
+    RMApp app1 = rm.submitApp(1024);
+    // kick the scheduling
+    nm1.nodeHeartbeat(true);
+    RMAppAttempt attempt1 = app1.getCurrentAppAttempt();
+    MockAM am1 = rm.sendAMLaunched(attempt1.getAppAttemptId());
+    am1.registerAppAttempt();
+    SchedulerNodeReport report_nm1 =
+        rm.getResourceScheduler().getNodeReport(nm1.getNodeId());
+
+    // check node report
+    Assert.assertEquals(1 * GB, report_nm1.getUsedResource().getMemory());
+    Assert.assertEquals(9 * GB, report_nm1.getAvailableResource().getMemory());
+
+    // add request for containers
+    am1.addRequests(new String[] { "127.0.0.1", "127.0.0.2" }, 1 * GB, 1, 1);
+    am1.schedule(); // send the request
+
+    // kick the scheduler, container reservation should not happen
+    nm1.nodeHeartbeat(true);
+    Thread.sleep(1000);
+    AllocateResponse allocResponse = am1.schedule();
+    ApplicationResourceUsageReport report =
+        rm.getResourceScheduler().getAppResourceUsageReport(
+          attempt1.getAppAttemptId());
+    Assert.assertEquals(0, allocResponse.getAllocatedContainers().size());
+    Assert.assertEquals(0, report.getNumReservedContainers());
+
+    // container should get allocated on this node
+    nm2.nodeHeartbeat(true);
+
+    while (allocResponse.getAllocatedContainers().size() == 0) {
+      Thread.sleep(100);
+      allocResponse = am1.schedule();
+    }
+    report =
+        rm.getResourceScheduler().getAppResourceUsageReport(
+          attempt1.getAppAttemptId());
+    Assert.assertEquals(1, allocResponse.getAllocatedContainers().size());
+    Assert.assertEquals(0, report.getNumReservedContainers());
+    rm.stop();
+  }
 }