YARN-1258. Allow configuring the Fair Scheduler root queue (Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1530543 13f79535-47bb-0310-9956-ffa450edef68

hadoop-yarn-project/CHANGES.txt

@@ -44,6 +44,8 @@ Release 2.3.0 - UNRELEASED
 
     YARN-976. Document the meaning of a virtual core. (Sandy Ryza)
 
+    YARN-1258. Allow configuring the Fair Scheduler root queue (Sandy Ryza)
+
   OPTIMIZATIONS
 
   BUG FIXES

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

@@ -302,16 +302,14 @@ public void reloadAllocs() throws IOException, ParserConfigurationException,
       throw new AllocationConfigurationException("Bad fair scheduler config " +
           "file: top-level element not <allocations>");
     NodeList elements = root.getChildNodes();
+    List<Element> queueElements = new ArrayList<Element>();
     for (int i = 0; i < elements.getLength(); i++) {
       Node node = elements.item(i);
-      if (!(node instanceof Element))
+      if (node instanceof Element) {
-        continue;
         Element element = (Element)node;
         if ("queue".equals(element.getTagName()) ||
       	  "pool".equals(element.getTagName())) {
-        loadQueue("root", element, minQueueResources, maxQueueResources, queueMaxApps,
+          queueElements.add(element);
-            userMaxApps, queueWeights, queuePolicies, minSharePreemptionTimeouts,
-            queueAcls, queueNamesInAllocFile);
         } else if ("user".equals(element.getTagName())) {
           String userName = element.getAttribute("name");
           NodeList fields = element.getChildNodes();
@@ -351,6 +349,23 @@ public void reloadAllocs() throws IOException, ParserConfigurationException,
           LOG.warn("Bad element in allocations file: " + element.getTagName());
         }
       }
+    }
+    
+    // Load queue elements.  A root queue can either be included or omitted.  If
+    // it's included, all other queues must be inside it.
+    for (Element element : queueElements) {
+      String parent = "root";
+      if (element.getAttribute("name").equalsIgnoreCase("root")) {
+        if (queueElements.size() > 1) {
+          throw new AllocationConfigurationException("If configuring root queue,"
+          		+ " no other queues can be placed alongside it.");
+        }
+        parent = null;
+      }
+      loadQueue(parent, element, minQueueResources, maxQueueResources, queueMaxApps,
+          userMaxApps, queueWeights, queuePolicies, minSharePreemptionTimeouts,
+          queueAcls, queueNamesInAllocFile);
+    }
 
     // Commit the reload; also create any queue defined in the alloc file
     // if it does not already exist, so it can be displayed on the web UI.
@@ -398,7 +413,10 @@ private void loadQueue(String parentName, Element element, Map<String, Resource>
       Map<String, Long> minSharePreemptionTimeouts,
       Map<String, Map<QueueACL, AccessControlList>> queueAcls, List<String> queueNamesInAllocFile) 
       throws AllocationConfigurationException {
-    String queueName = parentName + "." + element.getAttribute("name");
+    String queueName = element.getAttribute("name");
+    if (parentName != null) {
+      queueName = parentName + "." + queueName;
+    }
     Map<QueueACL, AccessControlList> acls =
         new HashMap<QueueACL, AccessControlList>();
     NodeList fields = element.getChildNodes();

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

@@ -923,14 +923,70 @@ public void testHierarchicalQueueAllocationFileParsing() throws IOException, SAX
     
     Collection<FSLeafQueue> leafQueues = queueManager.getLeafQueues();
     Assert.assertEquals(4, leafQueues.size());
-    Assert.assertNotNull(queueManager.getLeafQueue("queueA", true));
+    Assert.assertNotNull(queueManager.getLeafQueue("queueA", false));
-    Assert.assertNotNull(queueManager.getLeafQueue("queueB.queueC", true));
+    Assert.assertNotNull(queueManager.getLeafQueue("queueB.queueC", false));
-    Assert.assertNotNull(queueManager.getLeafQueue("queueB.queueD", true));
+    Assert.assertNotNull(queueManager.getLeafQueue("queueB.queueD", false));
-    Assert.assertNotNull(queueManager.getLeafQueue("default", true));
+    Assert.assertNotNull(queueManager.getLeafQueue("default", false));
     // Make sure querying for queues didn't create any new ones:
     Assert.assertEquals(4, leafQueues.size());
   }
   
+  @Test
+  public void testConfigureRootQueue() throws Exception {
+    Configuration conf = createConfiguration();
+    conf.set(FairSchedulerConfiguration.ALLOCATION_FILE, ALLOC_FILE);
+    scheduler.reinitialize(conf, resourceManager.getRMContext());
+
+    PrintWriter out = new PrintWriter(new FileWriter(ALLOC_FILE));
+    out.println("<?xml version=\"1.0\"?>");
+    out.println("<allocations>");
+    out.println("<defaultQueueSchedulingPolicy>fair</defaultQueueSchedulingPolicy>");
+    out.println("<queue name=\"root\">");
+    out.println("  <schedulingPolicy>drf</schedulingPolicy>");
+    out.println("  <queue name=\"child1\">");
+    out.println("    <minResources>1024mb,1vcores</minResources>");
+    out.println("  </queue>");
+    out.println("  <queue name=\"child2\">");
+    out.println("    <minResources>1024mb,4vcores</minResources>");
+    out.println("  </queue>");
+    out.println("</queue>");
+    out.println("</allocations>");
+    out.close();
+
+    QueueManager queueManager = scheduler.getQueueManager();
+    queueManager.initialize();
+    
+    FSQueue root = queueManager.getRootQueue();
+    assertTrue(root.getPolicy() instanceof DominantResourceFairnessPolicy);
+    
+    assertNotNull(queueManager.getLeafQueue("child1", false));
+    assertNotNull(queueManager.getLeafQueue("child2", false));
+  }
+  
+  /**
+   * Verify that you can't place queues at the same level as the root queue in
+   * the allocations file.
+   */
+  @Test (expected = AllocationConfigurationException.class)
+  public void testQueueAlongsideRoot() throws Exception {
+    Configuration conf = createConfiguration();
+    conf.set(FairSchedulerConfiguration.ALLOCATION_FILE, ALLOC_FILE);
+    scheduler.reinitialize(conf, resourceManager.getRMContext());
+
+    PrintWriter out = new PrintWriter(new FileWriter(ALLOC_FILE));
+    out.println("<?xml version=\"1.0\"?>");
+    out.println("<allocations>");
+    out.println("<queue name=\"root\">");
+    out.println("</queue>");
+    out.println("<queue name=\"other\">");
+    out.println("</queue>");
+    out.println("</allocations>");
+    out.close();
+
+    QueueManager queueManager = scheduler.getQueueManager();
+    queueManager.initialize();
+  }
+  
   @Test
   public void testBackwardsCompatibleAllocationFileParsing() throws Exception {
     Configuration conf = createConfiguration();