远程调试hadoop-2.2

近期一直在研究基于hadoop-2.2和hbase-0.96的安装配置，并结合官方文档简单的编写了一些mapreduce的例子。为了更深入了解hadoop-2.2的实现，决定研究一下如何对hadoop进行远程调试。

下面介绍利用eclipse远程调试工具进行hadoop的调试：

1. 在Shell脚本中运行命令：export YARN_CLIENT_OPTS="-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=8788"
2. 运行mapreduce job：yarn jar hbase-demo-0.0.1-SNAPSHOT.jar，命令行会显示一条信息：Listening for transport dt_socket at address: 8788，直到有客户端连接上调试后，程序才会继续往下进行。
3. 在eclipse中选择Run>Debug Configurations，在Remote Java Application下新建一个配置，选择mapreduce的实现工程，Host：[运行job机器的ip]，Port：8788，然后点击debug，和server建立debug连接，进入debug状态。

备注：调试hadoop不同的程序，需要设置不同的环境变量（YARN_CLIENT_OPTS），如何确定这个环境变量呢？请看hadoop/bin/yarn的shell脚本实现。在这里可以找到需要设置的相应环境变量和对应的主程序。

 

# figure out which class to run
if [ "$COMMAND" = "classpath" ] ; then
  echo $CLASSPATH
  exit
elif [ "$COMMAND" = "rmadmin" ] ; then
  CLASS='org.apache.hadoop.yarn.client.cli.RMAdminCLI'
  YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"
elif [ "$COMMAND" = "application" ] ; then
  CLASS=org.apache.hadoop.yarn.client.cli.ApplicationCLI
  YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"
elif [ "$COMMAND" = "node" ] ; then
  CLASS=org.apache.hadoop.yarn.client.cli.NodeCLI
  YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"
elif [ "$COMMAND" = "resourcemanager" ] ; then
  CLASSPATH=${CLASSPATH}:$YARN_CONF_DIR/rm-config/log4j.properties
  CLASS='org.apache.hadoop.yarn.server.resourcemanager.ResourceManager'
  YARN_OPTS="$YARN_OPTS $YARN_RESOURCEMANAGER_OPTS"
  if [ "$YARN_RESOURCEMANAGER_HEAPSIZE" != "" ]; then
    JAVA_HEAP_MAX="-Xmx""$YARN_RESOURCEMANAGER_HEAPSIZE""m"
  fi
elif [ "$COMMAND" = "nodemanager" ] ; then
  CLASSPATH=${CLASSPATH}:$YARN_CONF_DIR/nm-config/log4j.properties
  CLASS='org.apache.hadoop.yarn.server.nodemanager.NodeManager'
  YARN_OPTS="$YARN_OPTS -server $YARN_NODEMANAGER_OPTS"
  if [ "$YARN_NODEMANAGER_HEAPSIZE" != "" ]; then
    JAVA_HEAP_MAX="-Xmx""$YARN_NODEMANAGER_HEAPSIZE""m"
  fi
elif [ "$COMMAND" = "proxyserver" ] ; then
  CLASS='org.apache.hadoop.yarn.server.webproxy.WebAppProxyServer'
  YARN_OPTS="$YARN_OPTS $YARN_PROXYSERVER_OPTS"
  if [ "$YARN_PROXYSERVER_HEAPSIZE" != "" ]; then
    JAVA_HEAP_MAX="-Xmx""$YARN_PROXYSERVER_HEAPSIZE""m"
  fi
elif [ "$COMMAND" = "version" ] ; then
  CLASS=org.apache.hadoop.util.VersionInfo
  YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"
elif [ "$COMMAND" = "jar" ] ; then
  CLASS=org.apache.hadoop.util.RunJar
  YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"
elif [ "$COMMAND" = "logs" ] ; then
  CLASS=org.apache.hadoop.yarn.client.cli.LogsCLI
  YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"
elif [ "$COMMAND" = "daemonlog" ] ; then
  CLASS=org.apache.hadoop.log.LogLevel
  YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"
else
  CLASS=$COMMAND
fi