YARN-9883. Reshape SchedulerHealth class. Contributed by D M Murali Krishna Reddy

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

@@ -25,6 +25,31 @@ import org.apache.hadoop.yarn.api.records.Resource;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
+/**
+ * SchedulerHealth class holds the details of the schedulers operations.
+ *
+ * <p><code>SchedulerHealth</code> provides clients with information such as:
+ * <ol>
+ *   <li>
+ *   scheduler's latest timestamp
+ *   </li>
+ *   <li>
+ *   resources allocated, reserved, released in the last scheduler run
+ *   </li>
+ *   <li>
+ *   latest allocation, release, reservation, preemption details
+ *   </li>
+ *   <li>
+ *   count of latest allocation, release, reservation, preemption
+ *   </li>
+ *   <li>
+ *   aggregate count of latest allocation, release, reservation, preemption,
+ *   fulfilled reservation
+ *   </li>
+ *</ol>
+ *
+ */
+
 public class SchedulerHealth {
 
   static public class DetailedInformation {
@@ -62,22 +87,22 @@ public class SchedulerHealth {
     ALLOCATION, RELEASE, PREEMPTION, RESERVATION, FULFILLED_RESERVATION
   }
 
-  long lastSchedulerRunTime;
-  Map<Operation, Resource> lastSchedulerRunDetails;
-  Map<Operation, DetailedInformation> schedulerHealthDetails;
-  Map<Operation, Long> schedulerOperationCounts;
+  private long lastSchedulerRunTime;
+  private Map<Operation, Resource> lastSchedulerRunDetails;
+  private Map<Operation, DetailedInformation> lastSchedulerHealthDetails;
+  private Map<Operation, Long> schedulerOperationCounts;
   // this is for counts since the RM started, never reset
-  Map<Operation, Long> schedulerOperationAggregateCounts;
+  private Map<Operation, Long> schedulerOperationAggregateCounts;
 
-  public SchedulerHealth() {
+  SchedulerHealth() {
     lastSchedulerRunDetails = new ConcurrentHashMap<>();
-    schedulerHealthDetails = new ConcurrentHashMap<>();
+    lastSchedulerHealthDetails = new ConcurrentHashMap<>();
     schedulerOperationCounts = new ConcurrentHashMap<>();
     schedulerOperationAggregateCounts = new ConcurrentHashMap<>();
     for (Operation op : Operation.values()) {
       lastSchedulerRunDetails.put(op, Resource.newInstance(0, 0));
       schedulerOperationCounts.put(op, 0L);
-      schedulerHealthDetails.put(op, new DetailedInformation(0, null, null,
+      lastSchedulerHealthDetails.put(op, new DetailedInformation(0, null, null,
         null));
       schedulerOperationAggregateCounts.put(op, 0L);
     }
@@ -88,28 +113,28 @@ public class SchedulerHealth {
       ContainerId containerId, String queue) {
     DetailedInformation di =
         new DetailedInformation(timestamp, nodeId, containerId, queue);
-    schedulerHealthDetails.put(Operation.ALLOCATION, di);
+    lastSchedulerHealthDetails.put(Operation.ALLOCATION, di);
   }
 
   public void updateRelease(long timestamp, NodeId nodeId,
       ContainerId containerId, String queue) {
     DetailedInformation di =
         new DetailedInformation(timestamp, nodeId, containerId, queue);
-    schedulerHealthDetails.put(Operation.RELEASE, di);
+    lastSchedulerHealthDetails.put(Operation.RELEASE, di);
   }
 
   public void updatePreemption(long timestamp, NodeId nodeId,
       ContainerId containerId, String queue) {
     DetailedInformation di =
         new DetailedInformation(timestamp, nodeId, containerId, queue);
-    schedulerHealthDetails.put(Operation.PREEMPTION, di);
+    lastSchedulerHealthDetails.put(Operation.PREEMPTION, di);
   }
 
   public void updateReservation(long timestamp, NodeId nodeId,
       ContainerId containerId, String queue) {
     DetailedInformation di =
         new DetailedInformation(timestamp, nodeId, containerId, queue);
-    schedulerHealthDetails.put(Operation.RESERVATION, di);
+    lastSchedulerHealthDetails.put(Operation.RESERVATION, di);
   }
 
   public void updateSchedulerRunDetails(long timestamp, Resource allocated,
@@ -150,6 +175,11 @@ public class SchedulerHealth {
     schedulerOperationAggregateCounts.put(op, tmp + count);
   }
 
+  /**
+   * Get the timestamp of the latest scheduler operation.
+   *
+   * @return the scheduler's latest timestamp
+   */
   public long getLastSchedulerRunTime() {
     return lastSchedulerRunTime;
   }
@@ -158,34 +188,69 @@ public class SchedulerHealth {
     return lastSchedulerRunDetails.get(op);
   }
 
+  /**
+   * Get the resources allocated in the last scheduler run.
+   *
+   * @return resources allocated
+   */
   public Resource getResourcesAllocated() {
     return getResourceDetails(Operation.ALLOCATION);
   }
 
+  /**
+   * Get the resources reserved in the last scheduler run.
+   *
+   * @return resources reserved
+   */
   public Resource getResourcesReserved() {
     return getResourceDetails(Operation.RESERVATION);
   }
 
+  /**
+   * Get the resources released in the last scheduler run.
+   *
+   * @return resources released
+   */
   public Resource getResourcesReleased() {
     return getResourceDetails(Operation.RELEASE);
   }
 
   private DetailedInformation getDetailedInformation(Operation op) {
-    return schedulerHealthDetails.get(op);
+    return lastSchedulerHealthDetails.get(op);
   }
 
+  /**
+   * Get the details of last allocation.
+   *
+   * @return last allocation details
+   */
   public DetailedInformation getLastAllocationDetails() {
     return getDetailedInformation(Operation.ALLOCATION);
   }
 
+  /**
+   * Get the details of last release.
+   *
+   * @return last release details
+   */
   public DetailedInformation getLastReleaseDetails() {
     return getDetailedInformation(Operation.RELEASE);
   }
 
+  /**
+   * Get the details of last reservation.
+   *
+   * @return last reservation details
+   */
   public DetailedInformation getLastReservationDetails() {
     return getDetailedInformation(Operation.RESERVATION);
   }
 
+  /**
+   * Get the details of last preemption.
+   *
+   * @return last preemption details
+   */
   public DetailedInformation getLastPreemptionDetails() {
     return getDetailedInformation(Operation.PREEMPTION);
   }
@@ -194,18 +259,38 @@ public class SchedulerHealth {
     return schedulerOperationCounts.get(op);
   }
 
+  /**
+   * Get the count of allocation from the latest scheduler health report.
+   *
+   * @return allocation count
+   */
   public Long getAllocationCount() {
     return getOperationCount(Operation.ALLOCATION);
   }
 
+  /**
+   * Get the count of release from the latest scheduler health report.
+   *
+   * @return release count
+   */
   public Long getReleaseCount() {
     return getOperationCount(Operation.RELEASE);
   }
 
+  /**
+   * Get the count of reservation from the latest scheduler health report.
+   *
+   * @return reservation count
+   */
   public Long getReservationCount() {
     return getOperationCount(Operation.RESERVATION);
   }
 
+  /**
+   * Get the count of preemption from the latest scheduler health report.
+   *
+   * @return preemption count
+   */
   public Long getPreemptionCount() {
     return getOperationCount(Operation.PREEMPTION);
   }
@@ -214,22 +299,47 @@ public class SchedulerHealth {
     return schedulerOperationAggregateCounts.get(op);
   }
 
+  /**
+   * Get the aggregate of all the allocations count.
+   *
+   * @return aggregate allocation count
+   */
   public Long getAggregateAllocationCount() {
     return getAggregateOperationCount(Operation.ALLOCATION);
   }
 
+  /**
+   * Get the aggregate of all the release count.
+   *
+   * @return aggregate release count
+   */
   public Long getAggregateReleaseCount() {
     return getAggregateOperationCount(Operation.RELEASE);
   }
 
+  /**
+   * Get the aggregate of all the reservations count.
+   *
+   * @return aggregate reservation count
+   */
   public Long getAggregateReservationCount() {
     return getAggregateOperationCount(Operation.RESERVATION);
   }
 
+  /**
+   * Get the aggregate of all the preemption count.
+   *
+   * @return aggregate preemption count
+   */
   public Long getAggregatePreemptionCount() {
     return getAggregateOperationCount(Operation.PREEMPTION);
   }
 
+  /**
+   * Get the aggregate of all the fulfilled reservations count.
+   *
+   * @return aggregate fulfilled reservations count
+   */
   public Long getAggregateFulFilledReservationsCount() {
     return getAggregateOperationCount(Operation.FULFILLED_RESERVATION);
   }