HADOOP-11257. Update "hadoop jar" documentation to warn against using it for launching yarn jars (iwasakims via cmccabe)

(cherry picked from commit 10c98aed38)

hadoop-common-project/hadoop-common/src/main/bin/hadoop

@@ -31,6 +31,8 @@ function print_usage(){
   echo "  fs                   run a generic filesystem user client"
   echo "  version              print the version"
   echo "  jar <jar>            run a jar file"
+  echo "                       note: please use \"yarn jar\" to launch"
+  echo "                             YARN applications, not this command."
   echo "  checknative [-a|-h]  check native hadoop and compression libraries availability"
   echo "  distcp <srcurl> <desturl> copy file or directories recursively"
   echo "  archive -archiveName NAME -p <parent path> <src>* <dest> create a hadoop archive"
@@ -101,6 +103,9 @@ case $COMMAND in
       CLASS=org.apache.hadoop.util.VersionInfo
     elif [ "$COMMAND" = "jar" ] ; then
       CLASS=org.apache.hadoop.util.RunJar
+      if [[ -n "${YARN_OPTS}" ]] || [[ -n "${YARN_CLIENT_OPTS}" ]]; then
+        echo "WARNING: Use \"yarn jar\" to launch YARN applications."
+      fi
     elif [ "$COMMAND" = "key" ] ; then
       CLASS=org.apache.hadoop.crypto.key.KeyShell
     elif [ "$COMMAND" = "checknative" ] ; then

hadoop-common-project/hadoop-common/src/main/bin/hadoop.cmd

@@ -157,6 +157,11 @@ call :updatepath %HADOOP_BIN_PATH%
   goto :eof
 
 :version 
+  if defined YARN_OPTS (
+    @echo WARNING: Use "yarn jar" to launch YARN applications.
+  ) else if defined YARN_CLIENT_OPTS (
+    @echo WARNING: Use "yarn jar" to launch YARN applications.
+  )
   set CLASS=org.apache.hadoop.util.VersionInfo
   goto :eof
 
@@ -241,6 +246,8 @@ call :updatepath %HADOOP_BIN_PATH%
   goto :MakeCmdArgsLoop 
   :EndLoop 
   set hadoop-command-arguments=%_arguments%
+  @echo                        note: please use "yarn jar" to launch
+  @echo                              YARN applications, not this command.
   goto :eof
 
 :print_usage

hadoop-common-project/hadoop-common/src/site/apt/CommandsManual.apt.vm

@@ -177,6 +177,9 @@ User Commands
    Word count example is also run using jar command. It can be referred from
    Wordcount example
 
+   Use {{{../../hadoop-yarn/hadoop-yarn-site/YarnCommands.html#jar}<<<yarn jar>>>}}
+   to launch YARN applications instead.
+
 * <<<job>>>
 
    Deprecated. Use