YARN-4784. Fairscheduler: defaultQueueSchedulingPolicy should not accept FIFO. (Yufei Gu via kasha)

(cherry picked from commit 170c4fd4cd)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/AllocationFileLoaderService.java

@@ -42,6 +42,7 @@ import org.apache.hadoop.yarn.api.records.QueueACL;
 import org.apache.hadoop.yarn.api.records.ReservationACL;
 import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.server.resourcemanager.resource.ResourceWeights;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.FifoPolicy;
 import org.apache.hadoop.yarn.util.Clock;
 import org.apache.hadoop.yarn.util.SystemClock;
 import org.apache.hadoop.yarn.util.resource.Resources;
@@ -331,6 +332,11 @@ public class AllocationFileLoaderService extends AbstractService {
         } else if ("defaultQueueSchedulingPolicy".equals(element.getTagName())
             || "defaultQueueSchedulingMode".equals(element.getTagName())) {
           String text = ((Text)element.getFirstChild()).getData().trim();
+          if (text.equalsIgnoreCase(FifoPolicy.NAME)) {
+            throw new AllocationConfigurationException("Bad fair scheduler "
+              + "config file: defaultQueueSchedulingPolicy or "
+              + "defaultQueueSchedulingMode can't be FIFO.");
+          }
           defaultSchedPolicy = SchedulingPolicy.parse(text);
         } else if ("queuePlacementPolicy".equals(element.getTagName())) {
           placementPolicyElement = element;

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestAllocationFileLoaderService.java

@@ -580,6 +580,28 @@ public class TestAllocationFileLoaderService {
     allocLoader.reloadAllocations();
   }
 
+  /**
+   * Verify that defaultQueueSchedulingMode can't accept FIFO as a value.
+   */
+  @Test (expected = AllocationConfigurationException.class)
+  public void testDefaultQueueSchedulingModeIsFIFO() throws Exception {
+    Configuration conf = new Configuration();
+    conf.set(FairSchedulerConfiguration.ALLOCATION_FILE, ALLOC_FILE);
+
+    PrintWriter out = new PrintWriter(new FileWriter(ALLOC_FILE));
+    out.println("<?xml version=\"1.0\"?>");
+    out.println("<allocations>");
+    out.println("<defaultQueueSchedulingPolicy>fifo</defaultQueueSchedulingPolicy>");
+    out.println("</allocations>");
+    out.close();
+
+    AllocationFileLoaderService allocLoader = new AllocationFileLoaderService();
+    allocLoader.init(conf);
+    ReloadListener confHolder = new ReloadListener();
+    allocLoader.setReloadListener(confHolder);
+    allocLoader.reloadAllocations();
+  }
+
   @Test
   public void testReservableQueue() throws Exception {
     Configuration conf = new Configuration();