hadoop 伪分布式搭建

下载hadoop1.0.4版本，和jdk1.6版本或更高版本：
1. 安装JDK，安装目录大家可以自定义，下面是我的安装目录：

/usr/jdk1.6.0_22

配置环境变量：

[root@hadoop hadoop-1.0.4]# vi /etc/profile

将环境变量添加到profile文件底部：

export JAVA_HOME=/usr/jdk1.6.0_22
export PATH=$PATH:$JAVA_HOME/bin

激活环境变量：

[root@hadoop hadoop-1.0.4]# source /etc/profile

2. 安装hadoop
创建hadoop用户及其hadoop组。
配置IP对应域名在

[root@hadoop hadoop-1.0.4]$ vi /etc/hosts

在hosts文件底部中添加如下：

192.168.0.101   hadoop.master

接下来下载hadoop安装包，大家可以到apache官网下载1.0.4版本
我这里将hadoop安装到hadoop用户目录下，解压hadoop安装文件，hadoop有三个核心配置文件core-site.xml,hdfs-site.xml,mapred-site.xml，
配置core-site.xml

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
  <name>fs.default.name</name>
  <value>hdfs://hadoop.master:9000</value>
</property>
<property>
  <name>hadoop.tmp.dir</name>
  <value>/home/hadoop/tmp</value>
</property>
</configuration>

配置hdfs-site.xml

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
   <name>dfs.replication</name>
   <value>1</value>
</property>
<property>
  <name>dfs.name.dir</name>
  <value>/home/hadoop/hdfs/name</value>
</property>
<property>
  <name>dfs.data.dir</name>
  <value>/home/hadoop/hdfs/data</value>
</property>
</configuration>

配置 mapred-site.xml

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
   <name>mapred.job.tracker</name>
   <value>hadoop.master:9001</value>
</property>
</configuration>

最后配置haoop-env.sh文件

# Set Hadoop-specific environment variables here.

# The only required environment variable is JAVA_HOME.  All others are
# optional.  When running a distributed configuration it is best to
# set JAVA_HOME in this file, so that it is correctly defined on
# remote nodes.

# The java implementation to use.  Required.
export JAVA_HOME=/usr/jdk1.6.0_22

# Extra Java CLASSPATH elements.  Optional.
  export HADOOP_HOME=/home/hadoop/hadoop-1.0.4
# export HADOOP_CLASSPATH=

# The maximum amount of heap to use, in MB. Default is 1000.
# export HADOOP_HEAPSIZE=2000

# Extra Java runtime options.  Empty by default.
# export HADOOP_OPTS=-server

# Command specific options appended to HADOOP_OPTS when specified
export HADOOP_NAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_NAMENODE_OPTS"
export HADOOP_SECONDARYNAMENODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_SECONDARYNAMENODE_OPTS"
export HADOOP_DATANODE_OPTS="-Dcom.sun.management.jmxremote $HADOOP_DATANODE_OPTS"
export HADOOP_BALANCER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_BALANCER_OPTS"
export HADOOP_JOBTRACKER_OPTS="-Dcom.sun.management.jmxremote $HADOOP_JOBTRACKER_OPTS"
# export HADOOP_TASKTRACKER_OPTS=
# The following applies to multiple commands (fs, dfs, fsck, distcp etc)
# export HADOOP_CLIENT_OPTS

# Extra ssh options.  Empty by default.
# export HADOOP_SSH_OPTS="-o ConnectTimeout=1 -o SendEnv=HADOOP_CONF_DIR"

# Where log files are stored.  $HADOOP_HOME/logs by default.
# export HADOOP_LOG_DIR=${HADOOP_HOME}/logs

# File naming remote slave hosts.  $HADOOP_HOME/conf/slaves by default.
# export HADOOP_SLAVES=${HADOOP_HOME}/conf/slaves

# host:path where hadoop code should be rsync'd from.  Unset by default.
# export HADOOP_MASTER=master:/home/$USER/src/hadoop

# Seconds to sleep between slave commands.  Unset by default.  This
# can be useful in large clusters, where, e.g., slave rsyncs can
# otherwise arrive faster than the master can service them.
# export HADOOP_SLAVE_SLEEP=0.1

# The directory where pid files are stored. /tmp by default.
# export HADOOP_PID_DIR=/var/hadoop/pids

# A string representing this instance of hadoop. $USER by default.
# export HADOOP_IDENT_STRING=$USER

# The scheduling priority for daemon processes.  See 'man nice'.
# export HADOOP_NICENESS=10

  export PATH=$PATH:$HADOOP_HOME/bin

最后在配置hadoop环境变量在跟jdk在同一个文件，在jdk环境变量下面增加hadoop环境变量：

export JAVA_HOME=/usr/jdk1.8.0_151
export HADOOP_HOME=/usr/hadoop-2.6.1
export PATH=$JAVA_HOME/bin:$HADOOP_HOME/bin:$PATH

source /etc/profile

到这里所有环境配置已经完成：
再一次启动时需要namenode format，命令如下：

[hadoop@hadoop bin]$ hadoop namenode -format

格式完成后，启动hadoop，使用命令

[hadoop@hadoop bin]$ ./start-all.sh

使用jps查看hadoop启动的守护进程：

[hadoop@hadoop bin]$ jps
2734 NameNode
2860 DataNode
2996 SecondaryNameNode
3090 JobTracker
3261 TaskTracker

hadoop 伪分布式安装已经完成。