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

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

@@ -33,6 +33,8 @@ function hadoop_usage()
   echo "                       copy file or directories recursively"
   echo "  fs                   run a generic filesystem user client"
   echo "  jar <jar>            run a jar file"
+  echo "                       note: please use \"yarn jar\" to launch"
+  echo "                             YARN applications, not this command."
   echo "  jnipath              prints the java.library.path"
   echo "  key                  manage keys via the KeyProvider"
   echo "  trace                view and modify Hadoop tracing settings"
@@ -150,6 +152,9 @@ case ${COMMAND} in
     CLASS=org.apache.hadoop.fs.FsShell
   ;;
   jar)
+    if [[ -n "${YARN_OPTS}" ]] || [[ -n "${YARN_CLIENT_OPTS}" ]]; then
+      hadoop_error "WARNING: Use \"yarn jar\" to launch YARN applications."
+    fi
     CLASS=org.apache.hadoop.util.RunJar
   ;;
   jnipath)

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

@@ -177,6 +177,11 @@ 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
 
@@ -261,6 +266,8 @@ 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