HDFS-7458. Add description to the nfs ports in core-site.xml used by nfs test to avoid confusion. Contributed by Yongjun Zhang

(cherry picked from commit a1e822595c3dc5eadbd5430e57bc4691d09d5e68)

hadoop-hdfs-project/hadoop-hdfs-nfs/src/test/resources/core-site.xml

@@ -20,10 +20,24 @@
 <property>
   <name>nfs.server.port</name>
   <value>2079</value>
+  <description>
+    Specify the port number used by Hadoop NFS.
+    Notice that the default value here is different than the default Hadoop nfs
+    port 2049 specified in hdfs-default.xml. 2049 is also the default port for
+    Linux nfs. The setting here allows starting Hadoop nfs for testing even if
+    nfs server (linux or Hadoop) is aready running on he same host.
+  </description>
 </property>
 
 <property>
   <name>nfs.mountd.port</name>
   <value>4272</value>
+  <description>
+    Specify the port number used by Hadoop mount daemon.
+    Notice that the default value here is different than 4242 specified in 
+    hdfs-default.xml. This setting allows starting Hadoop nfs mountd for
+    testing even if the Linux or Hadoop mountd is already running on the
+    same host.
+  </description>
 </property>
 </configuration>

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

@@ -164,6 +164,9 @@ Release 2.7.0 - UNRELEASED
 
     HDFS-6735. A minor optimization to avoid pread() be blocked by read()
     inside the same DFSInputStream (Lars Hofhansl via stack)
+    
+    HDFS-7458. Add description to the nfs ports in core-site.xml used by nfs
+    test to avoid confusion (Yongjun Zhang via brandonli)
 
   OPTIMIZATIONS