Hadoop启动脚本全解析，不能再全了！[bed]

于 2013-10-27 18:47:00 发布 · 192 阅读 · 0
文章标签：

#大数据 #java #shell

本文详细解析了Cloudera Hadoop的启动脚本，包括启动流程、关键配置文件及参数设置等内容，帮助读者理解Hadoop组件启动机制。

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转自: http://blog.youkuaiyun.com/mrtitan/article/details/9115621

在工作过程中，经常需要调整一些hadoop的参数配置，所以经常会遇到各种各样的问题。比如改了个配置怎么突然namenode起不来啦，加了个jar包怎么让hadoop的jvm加载啊，如何设定log目录啦等等，每次都需要仔细的查一遍启动脚本才能找到原因，费时又费力，因此专门总结了一下以便不时之需。

cloudera的hadoop的启动脚本写的异常复杂和零散，各种shell脚本分散在系统的各个角落，让人很无语。下面以namenode启动的过程为例说明hadoop的启动脚本的调用关系和各个脚本的作用。

hadoop启动的入口脚本是/etc/init.d/hadoop-hdfs-name，下面我们顺着启动namenode的顺序看看hadoop的启动调用过程。

/etc/init.d/hadoop-hdfs-namenode：
#1.加载/etc/default/hadoop /etc/default/hadoop-hdfs-namenode

#2.执行/usr/lib/hadoop/sbin/hadoop-daemon.sh启动namenode


cloudera启动namenode的用户为hdfs，默认的配置目录是/etc/hadoop/conf

[plain] view plain copy print ?
  1. start(){
  2. [-x$EXEC_PATH]||exit$ERROR_PROGRAM_NOT_INSTALLED
  3. [-d$CONF_DIR]||exit$ERROR_PROGRAM_NOT_CONFIGURED
  4. log_success_msg"Starting${DESC}:"
  6. su-s/bin/bash$SVC_USER-c"$EXEC_PATH--config'$CONF_DIR'start$DAEMON_FLAGS"
  8. #Someprocessesareslowtostart
  9. sleep$SLEEP_TIME
  10. checkstatusofproc
  11. RETVAL=$?
  13. [$RETVAL-eq$RETVAL_SUCCESS]&&touch$LOCKFILE
  14. return$RETVAL
  15. }
start() {
  [ -x $EXEC_PATH ] || exit $ERROR_PROGRAM_NOT_INSTALLED
  [ -d $CONF_DIR ] || exit $ERROR_PROGRAM_NOT_CONFIGURED
  log_success_msg "Starting ${DESC}: "

  su -s /bin/bash $SVC_USER -c "$EXEC_PATH --config '$CONF_DIR' start $DAEMON_FLAGS"

  # Some processes are slow to start
  sleep $SLEEP_TIME
  checkstatusofproc
  RETVAL=$?

  [ $RETVAL -eq $RETVAL_SUCCESS ] && touch $LOCKFILE
  return $RETVAL
}

/etc/default/hadoop /etc/default/hadoop-hdfs-namenode：

#1.配置logdir，piddir，user

/usr/lib/hadoop/sbin/hadoop-daemon.sh
#1.加载/usr/lib/hadoop/libexec/hadoop-config.sh

[plain] view plain copy print ?
  1. DEFAULT_LIBEXEC_DIR="$bin"/../libexec
  2. HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-$DEFAULT_LIBEXEC_DIR}
  3. .$HADOOP_LIBEXEC_DIR/hadoop-config.sh
DEFAULT_LIBEXEC_DIR="$bin"/../libexec
HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-$DEFAULT_LIBEXEC_DIR}
. $HADOOP_LIBEXEC_DIR/hadoop-config.sh

#2.加载hadoop-env.sh

[plain] view plain copy print ?
  1. if[-f"${HADOOP_CONF_DIR}/hadoop-env.sh"];then
  2. ."${HADOOP_CONF_DIR}/hadoop-env.sh"
  3. fi
if [ -f "${HADOOP_CONF_DIR}/hadoop-env.sh" ]; then
  . "${HADOOP_CONF_DIR}/hadoop-env.sh"
fi

#3.指定log目录

[plain] view plain copy print ?
  1. #getlogdirectory
  2. if["$HADOOP_LOG_DIR"=""];then
  3. exportHADOOP_LOG_DIR="$HADOOP_PREFIX/logs"
  4. fi
# get log directory
if [ "$HADOOP_LOG_DIR" = "" ]; then
  export HADOOP_LOG_DIR="$HADOOP_PREFIX/logs"
fi

#4.补全log目录和log4j的logger等参数

[plain] view plain copy print ?
  1. exportHADOOP_LOGFILE=hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.log
  2. exportHADOOP_ROOT_LOGGER=${HADOOP_ROOT_LOGGER:-"INFO,RFA"}
  3. exportHADOOP_SECURITY_LOGGER=${HADOOP_SECURITY_LOGGER:-"INFO,RFAS"}
  4. exportHDFS_AUDIT_LOGGER=${HDFS_AUDIT_LOGGER:-"INFO,NullAppender"}
  5. log=$HADOOP_LOG_DIR/hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.out
  6. pid=$HADOOP_PID_DIR/hadoop-$HADOOP_IDENT_STRING-$command.pid
  7. HADOOP_STOP_TIMEOUT=${HADOOP_STOP_TIMEOUT:-5}
export HADOOP_LOGFILE=hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.log
export HADOOP_ROOT_LOGGER=${HADOOP_ROOT_LOGGER:-"INFO,RFA"}
export HADOOP_SECURITY_LOGGER=${HADOOP_SECURITY_LOGGER:-"INFO,RFAS"}
export HDFS_AUDIT_LOGGER=${HDFS_AUDIT_LOGGER:-"INFO,NullAppender"}
log=$HADOOP_LOG_DIR/hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.out
pid=$HADOOP_PID_DIR/hadoop-$HADOOP_IDENT_STRING-$command.pid
HADOOP_STOP_TIMEOUT=${HADOOP_STOP_TIMEOUT:-5}

#5.调用/usr/lib/hadoop-hdfs/bin/hdfs

[plain] view plain copy print ?
  1. hadoop_rotate_log$log
  2. echostarting$command,loggingto$log
  3. cd"$HADOOP_PREFIX"
  4. case$commandin
  5. namenode|secondarynamenode|datanode|journalnode|dfs|dfsadmin|fsck|balancer|zkfc)
  6. if[-z"$HADOOP_HDFS_HOME"];then
  7. hdfsScript="$HADOOP_PREFIX"/bin/hdfs
  8. else
  9. hdfsScript="$HADOOP_HDFS_HOME"/bin/hdfs
  10. fi
  11. nohupnice-n$HADOOP_NICENESS$hdfsScript--config$HADOOP_CONF_DIR$command"$@">"$log"2>&1</dev/null&
  12. ;;
  13. (*)
  14. nohupnice-n$HADOOP_NICENESS$hadoopScript--config$HADOOP_CONF_DIR$command"$@">"$log"2>&1</dev/null&
  15. ;;
  16. esac
  17. echo$!>$pid
  18. sleep1;head"$log"
  19. sleep3;
  20. if!ps-p$!>/dev/null;then
  21. exit1
  22. fi
hadoop_rotate_log $log
echo starting $command, logging to $log
cd "$HADOOP_PREFIX"
case $command in
  namenode|secondarynamenode|datanode|journalnode|dfs|dfsadmin|fsck|balancer|zkfc)
 if [ -z "$HADOOP_HDFS_HOME" ]; then
   hdfsScript="$HADOOP_PREFIX"/bin/hdfs
 else
   hdfsScript="$HADOOP_HDFS_HOME"/bin/hdfs
 fi
 nohup nice -n $HADOOP_NICENESS $hdfsScript --config $HADOOP_CONF_DIR $command "$@" > "$log" 2>&1 < /dev/null &
  ;;
  (*)
 nohup nice -n $HADOOP_NICENESS $hadoopScript --config $HADOOP_CONF_DIR $command "$@" > "$log" 2>&1 < /dev/null &
  ;;
esac
echo $! > $pid
sleep 1; head "$log"
sleep 3;
if ! ps -p $! > /dev/null ; then
  exit 1
fi

可以看到namenode的sysout输出到$log中，即log=$HADOOP_LOG_DIR/hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.out

/usr/lib/hadoop/libexec/hadoop-config.sh
#1.加载/usr/lib/hadoop/libexec/hadoop-layout.sh
hadoop-layout.sh主要描述了hadoop的lib的文件夹结构，主要内容如下

[plain] view plain copy print ?
  1. HADOOP_COMMON_DIR="./"
  2. HADOOP_COMMON_LIB_JARS_DIR="lib"
  3. HADOOP_COMMON_LIB_NATIVE_DIR="lib/native"
  4. HDFS_DIR="./"
  5. HDFS_LIB_JARS_DIR="lib"
  6. YARN_DIR="./"
  7. YARN_LIB_JARS_DIR="lib"
  8. MAPRED_DIR="./"
  9. MAPRED_LIB_JARS_DIR="lib"
  11. HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-"/usr/lib/hadoop/libexec"}
  12. HADOOP_CONF_DIR=${HADOOP_CONF_DIR:-"/etc/hadoop/conf"}
  13. HADOOP_COMMON_HOME=${HADOOP_COMMON_HOME:-"/usr/lib/hadoop"}
  14. HADOOP_HDFS_HOME=${HADOOP_HDFS_HOME:-"/usr/lib/hadoop-hdfs"}
  15. HADOOP_MAPRED_HOME=${HADOOP_MAPRED_HOME:-"/usr/lib/hadoop-0.20-mapreduce"}
  16. YARN_HOME=${YARN_HOME:-"/usr/lib/hadoop-yarn"}
HADOOP_COMMON_DIR="./"
HADOOP_COMMON_LIB_JARS_DIR="lib"
HADOOP_COMMON_LIB_NATIVE_DIR="lib/native"
HDFS_DIR="./"
HDFS_LIB_JARS_DIR="lib"
YARN_DIR="./"
YARN_LIB_JARS_DIR="lib"
MAPRED_DIR="./"
MAPRED_LIB_JARS_DIR="lib"

HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-"/usr/lib/hadoop/libexec"}
HADOOP_CONF_DIR=${HADOOP_CONF_DIR:-"/etc/hadoop/conf"}
HADOOP_COMMON_HOME=${HADOOP_COMMON_HOME:-"/usr/lib/hadoop"}
HADOOP_HDFS_HOME=${HADOOP_HDFS_HOME:-"/usr/lib/hadoop-hdfs"}
HADOOP_MAPRED_HOME=${HADOOP_MAPRED_HOME:-"/usr/lib/hadoop-0.20-mapreduce"}
YARN_HOME=${YARN_HOME:-"/usr/lib/hadoop-yarn"}

#2.指定HDFS和YARN的lib

[plain] view plain copy print ?
  1. HADOOP_COMMON_DIR=${HADOOP_COMMON_DIR:-"share/hadoop/common"}
  2. HADOOP_COMMON_LIB_JARS_DIR=${HADOOP_COMMON_LIB_JARS_DIR:-"share/hadoop/common/lib"}
  3. HADOOP_COMMON_LIB_NATIVE_DIR=${HADOOP_COMMON_LIB_NATIVE_DIR:-"lib/native"}
  4. HDFS_DIR=${HDFS_DIR:-"share/hadoop/hdfs"}
  5. HDFS_LIB_JARS_DIR=${HDFS_LIB_JARS_DIR:-"share/hadoop/hdfs/lib"}
  6. YARN_DIR=${YARN_DIR:-"share/hadoop/yarn"}
  7. YARN_LIB_JARS_DIR=${YARN_LIB_JARS_DIR:-"share/hadoop/yarn/lib"}
  8. MAPRED_DIR=${MAPRED_DIR:-"share/hadoop/mapreduce"}
  9. MAPRED_LIB_JARS_DIR=${MAPRED_LIB_JARS_DIR:-"share/hadoop/mapreduce/lib"}
  11. #therootoftheHadoopinstallation
  12. #SeeHADOOP-6255fordirectorystructurelayout
  13. HADOOP_DEFAULT_PREFIX=$(cd-P--"$common_bin"/..&&pwd-P)
  14. HADOOP_PREFIX=${HADOOP_PREFIX:-$HADOOP_DEFAULT_PREFIX}
  15. exportHADOOP_PREFIX
HADOOP_COMMON_DIR=${HADOOP_COMMON_DIR:-"share/hadoop/common"}
HADOOP_COMMON_LIB_JARS_DIR=${HADOOP_COMMON_LIB_JARS_DIR:-"share/hadoop/common/lib"}
HADOOP_COMMON_LIB_NATIVE_DIR=${HADOOP_COMMON_LIB_NATIVE_DIR:-"lib/native"}
HDFS_DIR=${HDFS_DIR:-"share/hadoop/hdfs"}
HDFS_LIB_JARS_DIR=${HDFS_LIB_JARS_DIR:-"share/hadoop/hdfs/lib"}
YARN_DIR=${YARN_DIR:-"share/hadoop/yarn"}
YARN_LIB_JARS_DIR=${YARN_LIB_JARS_DIR:-"share/hadoop/yarn/lib"}
MAPRED_DIR=${MAPRED_DIR:-"share/hadoop/mapreduce"}
MAPRED_LIB_JARS_DIR=${MAPRED_LIB_JARS_DIR:-"share/hadoop/mapreduce/lib"}

# the root of the Hadoop installation
# See HADOOP-6255 for directory structure layout
HADOOP_DEFAULT_PREFIX=$(cd -P -- "$common_bin"/.. && pwd -P)
HADOOP_PREFIX=${HADOOP_PREFIX:-$HADOOP_DEFAULT_PREFIX}
export HADOOP_PREFIX

#3.对slave文件判断。但cdh的hadoop不是依靠slave来启动集群的，而是要用户自己写集群启动脚本（也许是为了逼用户用他的CloudManager。。。）

#4.再次指定env文件

[plain] view plain copy print ?
  1. if[-f"${HADOOP_CONF_DIR}/hadoop-env.sh"];then
  2. ."${HADOOP_CONF_DIR}/hadoop-env.sh"
  3. fi
if [ -f "${HADOOP_CONF_DIR}/hadoop-env.sh" ]; then
  . "${HADOOP_CONF_DIR}/hadoop-env.sh"
fi

#5.指定java home

[plain] view plain copy print ?
  1. #AttempttosetJAVA_HOMEifitisnotset
  2. if[[-z$JAVA_HOME]];then
  3. #OnOSXusejava_home(or/Libraryforolderversions)
  4. if["Darwin"=="$(uname-s)"];then
  5. if[-x/usr/libexec/java_home];then
  6. exportJAVA_HOME=($(/usr/libexec/java_home))
  7. else
  8. exportJAVA_HOME=(/Library/Java/Home)
  9. fi
  10. fi
  12. #Bailifwedidnotdetectit
  13. if[[-z$JAVA_HOME]];then
  14. echo"Error:JAVA_HOMEisnotsetandcouldnotbefound."1>&2
  15. exit1
  16. fi
  17. fi
# Attempt to set JAVA_HOME if it is not set
if [[ -z $JAVA_HOME ]]; then
  # On OSX use java_home (or /Library for older versions)
  if [ "Darwin" == "$(uname -s)" ]; then
    if [ -x /usr/libexec/java_home ]; then
      export JAVA_HOME=($(/usr/libexec/java_home))
    else
      export JAVA_HOME=(/Library/Java/Home)
    fi
  fi

  # Bail if we did not detect it
  if [[ -z $JAVA_HOME ]]; then
    echo "Error: JAVA_HOME is not set and could not be found." 1>&2
    exit 1
  fi
fi

#6.指定Java程序启动的heapsize，如果用户在hadoop-env.sh中指定了HADOOP_HEAPSIZE字段则会覆盖默认值1000m

[plain] view plain copy print ?
  1. #someJavaparameters
  2. JAVA_HEAP_MAX=-Xmx1000m
  4. #checkenvvarswhichmightoverridedefaultargs
  5. if["$HADOOP_HEAPSIZE"!=""];then
  6. #echo"runwithheapsize$HADOOP_HEAPSIZE"
  7. JAVA_HEAP_MAX="-Xmx""$HADOOP_HEAPSIZE""m"
  8. #echo$JAVA_HEAP_MAX
  9. fi
# some Java parameters
JAVA_HEAP_MAX=-Xmx1000m

# check envvars which might override default args
if [ "$HADOOP_HEAPSIZE" != "" ]; then
  #echo "run with heapsize $HADOOP_HEAPSIZE"
  JAVA_HEAP_MAX="-Xmx""$HADOOP_HEAPSIZE""m"
  #echo $JAVA_HEAP_MAX
fi

#7.指定程序的classpath，一大串代码，总结下就是
HADOOP_CONF_DIR+HADOOP_CLASSPATH+HADOOP_COMMON_DIR+HADOOP_COMMON_LIB_JARS_DIR+
HADOOP_COMMON_LIB_JARS_DIR+HADOOP_COMMON_LIB_NATIVE_DIR+HDFS_DIR+HDFS_LIB_JARS_DIR
+YARN_DIR+YARN_LIB_JARS_DIR+MAPRED_DIR+MAPRED_LIB_JARS_DIR

有一个要注意的，hadoop比较贴心的提供了HADOOP_USER_CLASSPATH_FIRST属性，如何设置了，
则HADOOP_CLASSPATH（用户自定义classpath）会在hadoop自身的jar包前加载，用来解决用户
想最先加载自定义的jar包情况。

#8.指定HADOOP_OPTS，-Dhadoop.log.dir这些类似参数会在conf下的log4j配置中用到

[plain] view plain copy print ?
  1. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.log.dir=$HADOOP_LOG_DIR"
  2. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.log.file=$HADOOP_LOGFILE"
  3. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.home.dir=$HADOOP_PREFIX"
  4. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.id.str=$HADOOP_IDENT_STRING"
  5. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.root.logger=${HADOOP_ROOT_LOGGER:-INFO,console}"
  6. if["x$JAVA_LIBRARY_PATH"!="x"];then
  7. HADOOP_OPTS="$HADOOP_OPTS-Djava.library.path=$JAVA_LIBRARY_PATH"
  8. exportLD_LIBRARY_PATH=$LD_LIBRARY_PATH:$JAVA_LIBRARY_PATH
  9. fi
  10. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.policy.file=$HADOOP_POLICYFILE"
  12. #Disableipv6asitcancauseissues
  13. HADOOP_OPTS="$HADOOP_OPTS-Djava.net.preferIPv4Stack=true"
  15. <SPANstyle="FONT-SIZE:18px">
  16. </SPAN>
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.log.dir=$HADOOP_LOG_DIR"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.log.file=$HADOOP_LOGFILE"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.home.dir=$HADOOP_PREFIX"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.id.str=$HADOOP_IDENT_STRING"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.root.logger=${HADOOP_ROOT_LOGGER:-INFO,console}"
if [ "x$JAVA_LIBRARY_PATH" != "x" ]; then
  HADOOP_OPTS="$HADOOP_OPTS -Djava.library.path=$JAVA_LIBRARY_PATH"
  export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$JAVA_LIBRARY_PATH
fi
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.policy.file=$HADOOP_POLICYFILE"

# Disable ipv6 as it can cause issues
HADOOP_OPTS="$HADOOP_OPTS -Djava.net.preferIPv4Stack=true"

/usr/lib/hadoop-hdfs/bin/hdfs
#1.加载/usr/lib/hadoop/libexec/hdfs-config.sh，但好像没啥作用

#2.根据启动参数指定java的启动mainclass：

[plain] view plain copy print ?
  1. if["$COMMAND"="namenode"];then
  2. CLASS='org.apache.hadoop.hdfs.server.namenode.NameNode'
  3. HADOOP_OPTS="$HADOOP_OPTS$HADOOP_NAMENODE_OPTS"
if [ "$COMMAND" = "namenode" ] ; then
  CLASS='org.apache.hadoop.hdfs.server.namenode.NameNode'
  HADOOP_OPTS="$HADOOP_OPTS $HADOOP_NAMENODE_OPTS"
[plain] view plain copy print ?
  1. #3.启动Java程序
  2. exec"$JAVA"-Dproc_$COMMAND$JAVA_HEAP_MAX$HADOOP_OPTS$CLASS"$@"
#3.启动Java程序
exec "$JAVA" -Dproc_$COMMAND $JAVA_HEAP_MAX $HADOOP_OPTS $CLASS "$@"
[html] view plain copy print ?

最后介绍几个配置的小例子。

1.如何指定hadoop的log目录：

从启动脚本中看几个配置的优先级排序是hadoop-env.sh>hadoop-config.sh>/etc/default/hadoop，因此我们如果想指定hadoop的log目录只需在hadoop-env.sh中添加一行：

export HADOOP_LOG_DIR=xxxxx

2.如何添加自己的jar包到hadoop中被namenode，datanode使用

export HADOOP_CLASSPATH=xxxxx

3.如何单独设定namenode的java heapsize。

比如想设置namenode10G，datanode1G，这个就有点意思了。如果直接指定HADOOP_HEAPSIZE那么此参数会作用于namenode,datanode，而单独在namenode的参数中指定也会有点小问题哦，不过基本是可以使用的。

总之，由于hadoop的启动脚本极其多而且琐碎，再加上hbase hive的启动脚本都是类似的结构，导致在添加修改一些配置时会产生很多莫名的问题，大家也可以在使用的过程中细细体会啦

在工作过程中，经常需要调整一些hadoop的参数配置，所以经常会遇到各种各样的问题。比如改了个配置怎么突然namenode起不来啦，加了个jar包怎么让hadoop的jvm加载啊，如何设定log目录啦等等，每次都需要仔细的查一遍启动脚本才能找到原因，费时又费力，因此专门总结了一下以便不时之需。

cloudera的hadoop的启动脚本写的异常复杂和零散，各种shell脚本分散在系统的各个角落，让人很无语。下面以namenode启动的过程为例说明hadoop的启动脚本的调用关系和各个脚本的作用。

hadoop启动的入口脚本是/etc/init.d/hadoop-hdfs-name，下面我们顺着启动namenode的顺序看看hadoop的启动调用过程。

/etc/init.d/hadoop-hdfs-namenode：
#1.加载/etc/default/hadoop /etc/default/hadoop-hdfs-namenode

#2.执行/usr/lib/hadoop/sbin/hadoop-daemon.sh启动namenode


cloudera启动namenode的用户为hdfs，默认的配置目录是/etc/hadoop/conf

[plain] view plain copy print ?
  1. start(){
  2. [-x$EXEC_PATH]||exit$ERROR_PROGRAM_NOT_INSTALLED
  3. [-d$CONF_DIR]||exit$ERROR_PROGRAM_NOT_CONFIGURED
  4. log_success_msg"Starting${DESC}:"
  6. su-s/bin/bash$SVC_USER-c"$EXEC_PATH--config'$CONF_DIR'start$DAEMON_FLAGS"
  8. #Someprocessesareslowtostart
  9. sleep$SLEEP_TIME
  10. checkstatusofproc
  11. RETVAL=$?
  13. [$RETVAL-eq$RETVAL_SUCCESS]&&touch$LOCKFILE
  14. return$RETVAL
  15. }
start() {
  [ -x $EXEC_PATH ] || exit $ERROR_PROGRAM_NOT_INSTALLED
  [ -d $CONF_DIR ] || exit $ERROR_PROGRAM_NOT_CONFIGURED
  log_success_msg "Starting ${DESC}: "

  su -s /bin/bash $SVC_USER -c "$EXEC_PATH --config '$CONF_DIR' start $DAEMON_FLAGS"

  # Some processes are slow to start
  sleep $SLEEP_TIME
  checkstatusofproc
  RETVAL=$?

  [ $RETVAL -eq $RETVAL_SUCCESS ] && touch $LOCKFILE
  return $RETVAL
}

/etc/default/hadoop /etc/default/hadoop-hdfs-namenode：

#1.配置logdir，piddir，user

/usr/lib/hadoop/sbin/hadoop-daemon.sh
#1.加载/usr/lib/hadoop/libexec/hadoop-config.sh

[plain] view plain copy print ?
  1. DEFAULT_LIBEXEC_DIR="$bin"/../libexec
  2. HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-$DEFAULT_LIBEXEC_DIR}
  3. .$HADOOP_LIBEXEC_DIR/hadoop-config.sh
DEFAULT_LIBEXEC_DIR="$bin"/../libexec
HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-$DEFAULT_LIBEXEC_DIR}
. $HADOOP_LIBEXEC_DIR/hadoop-config.sh

#2.加载hadoop-env.sh

[plain] view plain copy print ?
  1. if[-f"${HADOOP_CONF_DIR}/hadoop-env.sh"];then
  2. ."${HADOOP_CONF_DIR}/hadoop-env.sh"
  3. fi
if [ -f "${HADOOP_CONF_DIR}/hadoop-env.sh" ]; then
  . "${HADOOP_CONF_DIR}/hadoop-env.sh"
fi

#3.指定log目录

[plain] view plain copy print ?
  1. #getlogdirectory
  2. if["$HADOOP_LOG_DIR"=""];then
  3. exportHADOOP_LOG_DIR="$HADOOP_PREFIX/logs"
  4. fi
# get log directory
if [ "$HADOOP_LOG_DIR" = "" ]; then
  export HADOOP_LOG_DIR="$HADOOP_PREFIX/logs"
fi

#4.补全log目录和log4j的logger等参数

[plain] view plain copy print ?
  1. exportHADOOP_LOGFILE=hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.log
  2. exportHADOOP_ROOT_LOGGER=${HADOOP_ROOT_LOGGER:-"INFO,RFA"}
  3. exportHADOOP_SECURITY_LOGGER=${HADOOP_SECURITY_LOGGER:-"INFO,RFAS"}
  4. exportHDFS_AUDIT_LOGGER=${HDFS_AUDIT_LOGGER:-"INFO,NullAppender"}
  5. log=$HADOOP_LOG_DIR/hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.out
  6. pid=$HADOOP_PID_DIR/hadoop-$HADOOP_IDENT_STRING-$command.pid
  7. HADOOP_STOP_TIMEOUT=${HADOOP_STOP_TIMEOUT:-5}
export HADOOP_LOGFILE=hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.log
export HADOOP_ROOT_LOGGER=${HADOOP_ROOT_LOGGER:-"INFO,RFA"}
export HADOOP_SECURITY_LOGGER=${HADOOP_SECURITY_LOGGER:-"INFO,RFAS"}
export HDFS_AUDIT_LOGGER=${HDFS_AUDIT_LOGGER:-"INFO,NullAppender"}
log=$HADOOP_LOG_DIR/hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.out
pid=$HADOOP_PID_DIR/hadoop-$HADOOP_IDENT_STRING-$command.pid
HADOOP_STOP_TIMEOUT=${HADOOP_STOP_TIMEOUT:-5}

#5.调用/usr/lib/hadoop-hdfs/bin/hdfs

[plain] view plain copy print ?
  1. hadoop_rotate_log$log
  2. echostarting$command,loggingto$log
  3. cd"$HADOOP_PREFIX"
  4. case$commandin
  5. namenode|secondarynamenode|datanode|journalnode|dfs|dfsadmin|fsck|balancer|zkfc)
  6. if[-z"$HADOOP_HDFS_HOME"];then
  7. hdfsScript="$HADOOP_PREFIX"/bin/hdfs
  8. else
  9. hdfsScript="$HADOOP_HDFS_HOME"/bin/hdfs
  10. fi
  11. nohupnice-n$HADOOP_NICENESS$hdfsScript--config$HADOOP_CONF_DIR$command"$@">"$log"2>&1</dev/null&
  12. ;;
  13. (*)
  14. nohupnice-n$HADOOP_NICENESS$hadoopScript--config$HADOOP_CONF_DIR$command"$@">"$log"2>&1</dev/null&
  15. ;;
  16. esac
  17. echo$!>$pid
  18. sleep1;head"$log"
  19. sleep3;
  20. if!ps-p$!>/dev/null;then
  21. exit1
  22. fi
hadoop_rotate_log $log
echo starting $command, logging to $log
cd "$HADOOP_PREFIX"
case $command in
  namenode|secondarynamenode|datanode|journalnode|dfs|dfsadmin|fsck|balancer|zkfc)
 if [ -z "$HADOOP_HDFS_HOME" ]; then
   hdfsScript="$HADOOP_PREFIX"/bin/hdfs
 else
   hdfsScript="$HADOOP_HDFS_HOME"/bin/hdfs
 fi
 nohup nice -n $HADOOP_NICENESS $hdfsScript --config $HADOOP_CONF_DIR $command "$@" > "$log" 2>&1 < /dev/null &
  ;;
  (*)
 nohup nice -n $HADOOP_NICENESS $hadoopScript --config $HADOOP_CONF_DIR $command "$@" > "$log" 2>&1 < /dev/null &
  ;;
esac
echo $! > $pid
sleep 1; head "$log"
sleep 3;
if ! ps -p $! > /dev/null ; then
  exit 1
fi

可以看到namenode的sysout输出到$log中，即log=$HADOOP_LOG_DIR/hadoop-$HADOOP_IDENT_STRING-$command-$HOSTNAME.out

/usr/lib/hadoop/libexec/hadoop-config.sh
#1.加载/usr/lib/hadoop/libexec/hadoop-layout.sh
hadoop-layout.sh主要描述了hadoop的lib的文件夹结构，主要内容如下

[plain] view plain copy print ?
  1. HADOOP_COMMON_DIR="./"
  2. HADOOP_COMMON_LIB_JARS_DIR="lib"
  3. HADOOP_COMMON_LIB_NATIVE_DIR="lib/native"
  4. HDFS_DIR="./"
  5. HDFS_LIB_JARS_DIR="lib"
  6. YARN_DIR="./"
  7. YARN_LIB_JARS_DIR="lib"
  8. MAPRED_DIR="./"
  9. MAPRED_LIB_JARS_DIR="lib"
  11. HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-"/usr/lib/hadoop/libexec"}
  12. HADOOP_CONF_DIR=${HADOOP_CONF_DIR:-"/etc/hadoop/conf"}
  13. HADOOP_COMMON_HOME=${HADOOP_COMMON_HOME:-"/usr/lib/hadoop"}
  14. HADOOP_HDFS_HOME=${HADOOP_HDFS_HOME:-"/usr/lib/hadoop-hdfs"}
  15. HADOOP_MAPRED_HOME=${HADOOP_MAPRED_HOME:-"/usr/lib/hadoop-0.20-mapreduce"}
  16. YARN_HOME=${YARN_HOME:-"/usr/lib/hadoop-yarn"}
HADOOP_COMMON_DIR="./"
HADOOP_COMMON_LIB_JARS_DIR="lib"
HADOOP_COMMON_LIB_NATIVE_DIR="lib/native"
HDFS_DIR="./"
HDFS_LIB_JARS_DIR="lib"
YARN_DIR="./"
YARN_LIB_JARS_DIR="lib"
MAPRED_DIR="./"
MAPRED_LIB_JARS_DIR="lib"

HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-"/usr/lib/hadoop/libexec"}
HADOOP_CONF_DIR=${HADOOP_CONF_DIR:-"/etc/hadoop/conf"}
HADOOP_COMMON_HOME=${HADOOP_COMMON_HOME:-"/usr/lib/hadoop"}
HADOOP_HDFS_HOME=${HADOOP_HDFS_HOME:-"/usr/lib/hadoop-hdfs"}
HADOOP_MAPRED_HOME=${HADOOP_MAPRED_HOME:-"/usr/lib/hadoop-0.20-mapreduce"}
YARN_HOME=${YARN_HOME:-"/usr/lib/hadoop-yarn"}

#2.指定HDFS和YARN的lib

[plain] view plain copy print ?
  1. HADOOP_COMMON_DIR=${HADOOP_COMMON_DIR:-"share/hadoop/common"}
  2. HADOOP_COMMON_LIB_JARS_DIR=${HADOOP_COMMON_LIB_JARS_DIR:-"share/hadoop/common/lib"}
  3. HADOOP_COMMON_LIB_NATIVE_DIR=${HADOOP_COMMON_LIB_NATIVE_DIR:-"lib/native"}
  4. HDFS_DIR=${HDFS_DIR:-"share/hadoop/hdfs"}
  5. HDFS_LIB_JARS_DIR=${HDFS_LIB_JARS_DIR:-"share/hadoop/hdfs/lib"}
  6. YARN_DIR=${YARN_DIR:-"share/hadoop/yarn"}
  7. YARN_LIB_JARS_DIR=${YARN_LIB_JARS_DIR:-"share/hadoop/yarn/lib"}
  8. MAPRED_DIR=${MAPRED_DIR:-"share/hadoop/mapreduce"}
  9. MAPRED_LIB_JARS_DIR=${MAPRED_LIB_JARS_DIR:-"share/hadoop/mapreduce/lib"}
  11. #therootoftheHadoopinstallation
  12. #SeeHADOOP-6255fordirectorystructurelayout
  13. HADOOP_DEFAULT_PREFIX=$(cd-P--"$common_bin"/..&&pwd-P)
  14. HADOOP_PREFIX=${HADOOP_PREFIX:-$HADOOP_DEFAULT_PREFIX}
  15. exportHADOOP_PREFIX
HADOOP_COMMON_DIR=${HADOOP_COMMON_DIR:-"share/hadoop/common"}
HADOOP_COMMON_LIB_JARS_DIR=${HADOOP_COMMON_LIB_JARS_DIR:-"share/hadoop/common/lib"}
HADOOP_COMMON_LIB_NATIVE_DIR=${HADOOP_COMMON_LIB_NATIVE_DIR:-"lib/native"}
HDFS_DIR=${HDFS_DIR:-"share/hadoop/hdfs"}
HDFS_LIB_JARS_DIR=${HDFS_LIB_JARS_DIR:-"share/hadoop/hdfs/lib"}
YARN_DIR=${YARN_DIR:-"share/hadoop/yarn"}
YARN_LIB_JARS_DIR=${YARN_LIB_JARS_DIR:-"share/hadoop/yarn/lib"}
MAPRED_DIR=${MAPRED_DIR:-"share/hadoop/mapreduce"}
MAPRED_LIB_JARS_DIR=${MAPRED_LIB_JARS_DIR:-"share/hadoop/mapreduce/lib"}

# the root of the Hadoop installation
# See HADOOP-6255 for directory structure layout
HADOOP_DEFAULT_PREFIX=$(cd -P -- "$common_bin"/.. && pwd -P)
HADOOP_PREFIX=${HADOOP_PREFIX:-$HADOOP_DEFAULT_PREFIX}
export HADOOP_PREFIX

#3.对slave文件判断。但cdh的hadoop不是依靠slave来启动集群的，而是要用户自己写集群启动脚本（也许是为了逼用户用他的CloudManager。。。）

#4.再次指定env文件

[plain] view plain copy print ?
  1. if[-f"${HADOOP_CONF_DIR}/hadoop-env.sh"];then
  2. ."${HADOOP_CONF_DIR}/hadoop-env.sh"
  3. fi
if [ -f "${HADOOP_CONF_DIR}/hadoop-env.sh" ]; then
  . "${HADOOP_CONF_DIR}/hadoop-env.sh"
fi

#5.指定java home

[plain] view plain copy print ?
  1. #AttempttosetJAVA_HOMEifitisnotset
  2. if[[-z$JAVA_HOME]];then
  3. #OnOSXusejava_home(or/Libraryforolderversions)
  4. if["Darwin"=="$(uname-s)"];then
  5. if[-x/usr/libexec/java_home];then
  6. exportJAVA_HOME=($(/usr/libexec/java_home))
  7. else
  8. exportJAVA_HOME=(/Library/Java/Home)
  9. fi
  10. fi
  12. #Bailifwedidnotdetectit
  13. if[[-z$JAVA_HOME]];then
  14. echo"Error:JAVA_HOMEisnotsetandcouldnotbefound."1>&2
  15. exit1
  16. fi
  17. fi
# Attempt to set JAVA_HOME if it is not set
if [[ -z $JAVA_HOME ]]; then
  # On OSX use java_home (or /Library for older versions)
  if [ "Darwin" == "$(uname -s)" ]; then
    if [ -x /usr/libexec/java_home ]; then
      export JAVA_HOME=($(/usr/libexec/java_home))
    else
      export JAVA_HOME=(/Library/Java/Home)
    fi
  fi

  # Bail if we did not detect it
  if [[ -z $JAVA_HOME ]]; then
    echo "Error: JAVA_HOME is not set and could not be found." 1>&2
    exit 1
  fi
fi

#6.指定Java程序启动的heapsize，如果用户在hadoop-env.sh中指定了HADOOP_HEAPSIZE字段则会覆盖默认值1000m

[plain] view plain copy print ?
  1. #someJavaparameters
  2. JAVA_HEAP_MAX=-Xmx1000m
  4. #checkenvvarswhichmightoverridedefaultargs
  5. if["$HADOOP_HEAPSIZE"!=""];then
  6. #echo"runwithheapsize$HADOOP_HEAPSIZE"
  7. JAVA_HEAP_MAX="-Xmx""$HADOOP_HEAPSIZE""m"
  8. #echo$JAVA_HEAP_MAX
  9. fi
# some Java parameters
JAVA_HEAP_MAX=-Xmx1000m

# check envvars which might override default args
if [ "$HADOOP_HEAPSIZE" != "" ]; then
  #echo "run with heapsize $HADOOP_HEAPSIZE"
  JAVA_HEAP_MAX="-Xmx""$HADOOP_HEAPSIZE""m"
  #echo $JAVA_HEAP_MAX
fi

#7.指定程序的classpath，一大串代码，总结下就是
HADOOP_CONF_DIR+HADOOP_CLASSPATH+HADOOP_COMMON_DIR+HADOOP_COMMON_LIB_JARS_DIR+
HADOOP_COMMON_LIB_JARS_DIR+HADOOP_COMMON_LIB_NATIVE_DIR+HDFS_DIR+HDFS_LIB_JARS_DIR
+YARN_DIR+YARN_LIB_JARS_DIR+MAPRED_DIR+MAPRED_LIB_JARS_DIR

有一个要注意的，hadoop比较贴心的提供了HADOOP_USER_CLASSPATH_FIRST属性，如何设置了，
则HADOOP_CLASSPATH（用户自定义classpath）会在hadoop自身的jar包前加载，用来解决用户
想最先加载自定义的jar包情况。

#8.指定HADOOP_OPTS，-Dhadoop.log.dir这些类似参数会在conf下的log4j配置中用到

[plain] view plain copy print ?
  1. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.log.dir=$HADOOP_LOG_DIR"
  2. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.log.file=$HADOOP_LOGFILE"
  3. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.home.dir=$HADOOP_PREFIX"
  4. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.id.str=$HADOOP_IDENT_STRING"
  5. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.root.logger=${HADOOP_ROOT_LOGGER:-INFO,console}"
  6. if["x$JAVA_LIBRARY_PATH"!="x"];then
  7. HADOOP_OPTS="$HADOOP_OPTS-Djava.library.path=$JAVA_LIBRARY_PATH"
  8. exportLD_LIBRARY_PATH=$LD_LIBRARY_PATH:$JAVA_LIBRARY_PATH
  9. fi
  10. HADOOP_OPTS="$HADOOP_OPTS-Dhadoop.policy.file=$HADOOP_POLICYFILE"
  12. #Disableipv6asitcancauseissues
  13. HADOOP_OPTS="$HADOOP_OPTS-Djava.net.preferIPv4Stack=true"
  15. <SPANstyle="FONT-SIZE:18px">
  16. </SPAN>
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.log.dir=$HADOOP_LOG_DIR"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.log.file=$HADOOP_LOGFILE"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.home.dir=$HADOOP_PREFIX"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.id.str=$HADOOP_IDENT_STRING"
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.root.logger=${HADOOP_ROOT_LOGGER:-INFO,console}"
if [ "x$JAVA_LIBRARY_PATH" != "x" ]; then
  HADOOP_OPTS="$HADOOP_OPTS -Djava.library.path=$JAVA_LIBRARY_PATH"
  export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$JAVA_LIBRARY_PATH
fi
HADOOP_OPTS="$HADOOP_OPTS -Dhadoop.policy.file=$HADOOP_POLICYFILE"

# Disable ipv6 as it can cause issues
HADOOP_OPTS="$HADOOP_OPTS -Djava.net.preferIPv4Stack=true"

/usr/lib/hadoop-hdfs/bin/hdfs
#1.加载/usr/lib/hadoop/libexec/hdfs-config.sh，但好像没啥作用

#2.根据启动参数指定java的启动mainclass：

[plain] view plain copy print ?
  1. if["$COMMAND"="namenode"];then
  2. CLASS='org.apache.hadoop.hdfs.server.namenode.NameNode'
  3. HADOOP_OPTS="$HADOOP_OPTS$HADOOP_NAMENODE_OPTS"
if [ "$COMMAND" = "namenode" ] ; then
  CLASS='org.apache.hadoop.hdfs.server.namenode.NameNode'
  HADOOP_OPTS="$HADOOP_OPTS $HADOOP_NAMENODE_OPTS"
[plain] view plain copy print ?
  1. #3.启动Java程序
  2. exec"$JAVA"-Dproc_$COMMAND$JAVA_HEAP_MAX$HADOOP_OPTS$CLASS"$@"
#3.启动Java程序
exec "$JAVA" -Dproc_$COMMAND $JAVA_HEAP_MAX $HADOOP_OPTS $CLASS "$@"
[html] view plain copy print ? 
 

 

 

最后介绍几个配置的小例子。
 

1.如何指定hadoop的log目录：
 

从启动脚本中看几个配置的优先级排序是hadoop-env.sh>hadoop-config.sh>/etc/default/hadoop，因此我们如果想指定hadoop的log目录只需在hadoop-env.sh中添加一行：
 

export HADOOP_LOG_DIR=xxxxx
 

2.如何添加自己的jar包到hadoop中被namenode，datanode使用
 

export HADOOP_CLASSPATH=xxxxx
 

3.如何单独设定namenode的java heapsize。
 

比如想设置namenode10G，datanode1G，这个就有点意思了。如果直接指定HADOOP_HEAPSIZE那么此参数会作用于namenode,datanode，而单独在namenode的参数中指定也会有点小问题哦，不过基本是可以使用的。
 

 

总之，由于hadoop的启动脚本极其多而且琐碎，再加上hbase hive的启动脚本都是类似的结构，导致在添加修改一些配置时会产生很多莫名的问题，大家也可以在使用的过程中细细体会啦
 


                

        




    

    
  



    

      

        

            

              
                
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