HDFS-14526. RBF: Update the document of RBF related metrics. Contributed by Takanobu Asanuma.

hadoop-common-project/hadoop-common/src/site/markdown/Metrics.md

@@ -478,6 +478,40 @@ contains tags such as Hostname as additional information along with metrics.
 | `FileIoErrorRateNumOps` | The number of file io error operations within an interval time of metric |
 | `FileIoErrorRateAvgTime` | It measures the mean time in milliseconds from the start of an operation to hitting a failure |
 
+RBFMetrics
+----------------
+RBFMetrics shows the metrics which are the aggregated values of sub-clusters' information in the Router-based federation.
+
+| Name | Description |
+|:---- |:---- |
+| `NumFiles` | Current number of files and directories |
+| `NumBlocks` | Current number of allocated blocks |
+| `NumOfBlocksPendingReplication` | Current number of blocks pending to be replicated |
+| `NumOfBlocksUnderReplicated` | Current number of blocks under replicated |
+| `NumOfBlocksPendingDeletion` | Current number of blocks pending deletion |
+| `ProvidedSpace` | The total remote storage capacity mounted in the federated cluster |
+| `NumInMaintenanceLiveDataNodes` | Number of live Datanodes which are in maintenance state |
+| `NumInMaintenanceDeadDataNodes` | Number of dead Datanodes which are in maintenance state |
+| `NumEnteringMaintenanceDataNodes` | Number of Datanodes that are entering the maintenance state |
+| `TotalCapacity` | Current raw capacity of DataNodes in bytes |
+| `UsedCapacity` | Current used capacity across all DataNodes in bytes |
+| `RemainingCapacity` | Current remaining capacity in bytes |
+| `NumOfMissingBlocks` | Current number of missing blocks |
+| `NumLiveNodes` | Number of datanodes which are currently live |
+| `NumDeadNodes` | Number of datanodes which are currently dead |
+| `NumStaleNodes` | Current number of DataNodes marked stale due to delayed heartbeat |
+| `NumDecomLiveNodes` | Number of datanodes which have been decommissioned and are now live |
+| `NumDecomDeadNodes` | Number of datanodes which have been decommissioned and are now dead |
+| `NumDecommissioningNodes` | Number of datanodes in decommissioning state |
+| `Namenodes` | Current information about all the namenodes |
+| `Nameservices` | Current information for each registered nameservice |
+| `MountTable` | The mount table for the federated filesystem |
+| `Routers` | Current information about all routers |
+| `NumNameservices` | Number of nameservices |
+| `NumNamenodes` | Number of namenodes |
+| `NumExpiredNamenodes` | Number of expired namenodes |
+| `NodeUsage` | Max, Median, Min and Standard Deviation of DataNodes usage |
+
 RouterRPCMetrics
 ----------------
 RouterRPCMetrics shows the statistics of the Router component in Router-based federation.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/RBFMetrics.java

@@ -77,6 +77,7 @@ import org.apache.hadoop.hdfs.server.federation.store.records.MembershipStats;
 import org.apache.hadoop.hdfs.server.federation.store.records.MountTable;
 import org.apache.hadoop.hdfs.server.federation.store.records.RouterState;
 import org.apache.hadoop.hdfs.server.federation.store.records.StateStoreVersion;
+import org.apache.hadoop.metrics2.annotation.Metrics;
 import org.apache.hadoop.metrics2.util.MBeans;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.util.StringUtils;
@@ -91,6 +92,7 @@ import com.google.common.annotations.VisibleForTesting;
 /**
  * Implementation of the Router metrics collector.
  */
+@Metrics(name="RBFActivity", about="RBF metrics", context="dfs")
 public class RBFMetrics implements RouterMBean, FederationMBean {
 
   private static final Logger LOG =

hadoop-hdfs-project/hadoop-hdfs-rbf/src/site/markdown/HDFSRouterFederation.md

@@ -473,4 +473,4 @@ Metrics
 -------
 
 The Router and State Store statistics are exposed in metrics/JMX. These info will be very useful for monitoring.
-More metrics info can see [Router RPC Metrics](../../hadoop-project-dist/hadoop-common/Metrics.html#RouterRPCMetrics) and [State Store Metrics](../../hadoop-project-dist/hadoop-common/Metrics.html#StateStoreMetrics).
+More metrics info can see [RBF Metrics](../../hadoop-project-dist/hadoop-common/Metrics.html#RBFMetrics), [Router RPC Metrics](../../hadoop-project-dist/hadoop-common/Metrics.html#RouterRPCMetrics) and [State Store Metrics](../../hadoop-project-dist/hadoop-common/Metrics.html#StateStoreMetrics).