HDFS-7772. Document hdfs balancer -exclude/-include option in HDFSCommands.html. Contributed by Xiaoyu Yao.

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -354,6 +354,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-7780. Update use of Iterator to Iterable in DataXceiverServer and
     SnapshotDiffInfo. (Ray Chiang via aajisaka)
 
+    HDFS-7772. Document hdfs balancer -exclude/-include option in
+    HDFSCommands.html (Xiaoyu Yao via cnauroth)
+
   OPTIMIZATIONS
 
     HDFS-7454. Reduce memory footprint for AclEntries in NameNode.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java

@@ -171,15 +171,14 @@ public class Balancer {
   private static final long GB = 1L << 30; //1GB
   private static final long MAX_SIZE_TO_MOVE = 10*GB;
 
-  private static final String USAGE = "Usage: java "
-      + Balancer.class.getSimpleName()
+  private static final String USAGE = "Usage: hdfs balancer"
       + "\n\t[-policy <policy>]\tthe balancing policy: "
       + BalancingPolicy.Node.INSTANCE.getName() + " or "
       + BalancingPolicy.Pool.INSTANCE.getName()
       + "\n\t[-threshold <threshold>]\tPercentage of disk capacity"
-      + "\n\t[-exclude [-f <hosts-file> | comma-sperated list of hosts]]"
+      + "\n\t[-exclude [-f <hosts-file> | <comma-separated list of hosts>]]"
       + "\tExcludes the specified datanodes."
-      + "\n\t[-include [-f <hosts-file> | comma-sperated list of hosts]]"
+      + "\n\t[-include [-f <hosts-file> | <comma-separated list of hosts>]]"
       + "\tIncludes only the specified datanodes."
       + "\n\t[-idleiterations <idleiterations>]"
       + "\tNumber of consecutive idle iterations (-1 for Infinite) before exit.";

hadoop-hdfs-project/hadoop-hdfs/src/site/apt/HDFSCommands.apt.vm

@@ -134,7 +134,14 @@ HDFS Commands Guide
    to stop the rebalancing process. See
    {{{./HdfsUserGuide.html#Balancer}Balancer}} for more details.
 
-   Usage: <<<hdfs balancer [-threshold <threshold>] [-policy <policy>] [-idleiterations <idleiterations>]>>>
++------------------------------------------+
+   Usage: hdfs balancer
+           [-threshold <threshold>]
+           [-policy <policy>]
+           [-exclude [-f <hosts-file> | <comma-separated list of hosts>]]
+           [-include [-f <hosts-file> | <comma-separated list of hosts>]]
+           [-idleiterations <idleiterations>]
++------------------------------------------+
 
 *------------------------+----------------------------------------------------+
 || COMMAND_OPTION        | Description
@@ -147,6 +154,12 @@ HDFS Commands Guide
 |                        | <<<blockpool>>>: Cluster is balanced if each block
 |                        | pool in each datanode is balanced.
 *------------------------+----------------------------------------------------+
+| -exclude -f \<hosts-file\> \|       | Excludes the specified datanodes from
+|   \<comma-separated list of hosts\> | being balanced by the balancer.
+*------------------------+----------------------------------------------------+
+| -include -f \<hosts-file\> \|       | Includes only the specified datanode
+|   \<comma-separated list of hosts\> | to be balanced by the balancer.
+*------------------------+----------------------------------------------------+
 | -idleiterations <iterations> | Maximum number of idle iterations before exit.
 |                              | This overwrites the default idleiterations(5).
 *------------------------+----------------------------------------------------+