1 把定制的配置文件和hadoop源码分开，这样升级hadoop版本的时候，不需要重新修改配置文件；
2 经常要在集群模式/单点模式下进行切换
硬件准备情况：
有4台机器，一台作为namenode，三台作为datanode，机器名分配如下
10.2.224.24 namenode
10.2.224.25 datanode1
10.2.224.26 datanode2
10.2.224.27 datanode3
环境搭建步骤
1.在每台机器上创建一个admin用户，打通从namenode到各个datanode的ssh通道，这个在网上资料很多，不再描述；
2.mkdir /home/admin/hadoop-installed
3. 在 /home/admin/hadoop-installed目录下解压hadoop压缩包，解压为hadoop
4. mkdir /home/admin/hadoop-installed/cluster-conf
5. 在cluster-conf目录下创建如下四个文件
masters
[quote]
namenode #namenode机器的机器名
[/quote]
slaves
[quote]
datanode1
datanode2
datanode3
[/quote]
hadoop-site.xml
[quote]
<?xml version=”1.0″?>
<?xml-stylesheet type=”text/xsl” href=”configuration.xsl”?>
<configuration>
<property>
<name>hadoop.tmp.dir</name>
<value>/home/admin/hadoop-installed/filesystem</value>
</property>
<property>
<name>fs.default.name</name>
<value>hdfs://namenode:54310</value>
</property>
<property>
<name>mapred.job.tracker</name>
<value>hdsf://namenode:54311</value>
</property>
<property>
<name>dfs.replication</name>
<value>3</value>
</property>
<property>
<name>mapred.child.java.opts</name>
<value>-Xmx512m</value>
</property>
</configuration>
[/quote]
hadoop-env.sh
[quote]
export JAVA_HOME=/usr/ali/java
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_LOG_DIR=/home/admin/hadoop-installed/logs
[/quote]
6.增加环境变量HADOOP_CONF_DIR
[quote]
export HADOOP_CONF_DIR=/home/alisoft/hadoop-installed/conf
[/quote]
7.增加single-conf目录，在该目录下也增加如下四个文件
masters
[quote]
localhost #namenode机器的机器名
[/quote]
slaves
[quote]
localhost
[/quote]
hadoop-site.xml
[quote]
<?xml version=”1.0″?>
<?xml-stylesheet type=”text/xsl” href=”configuration.xsl”?>
<!– Put site-specific property overrides in this file. –>
<configuration>
<property>
<name>hadoop.tmp.dir</name>
<value>/home/admin/hadoop-installed/filesystem</value>
</property>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:54310</value>
</property>
<property>
<name>mapred.job.tracker</name>
<value>hdsf://localhost:54311</value>
</property>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
<property>
<name>mapred.child.java.opts</name>
<value>-Xmx512m</value>
</property>
</configuration>
[/quote]
hadoop-env.sh
[quote]
export JAVA_HOME=/usr/ali/java
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_LOG_DIR=/home/alisoft/hadoop-installed/logs
[/quote]
8. ln -s cluster-conf/ conf 集群模式
或者 ln -s single-conf/ conf 单机调试模式
9. 增加一个同步脚本
[quote]
DESTSERVER=’datanode1 datanode2 datanode3′
for DEST in $DESTSERVER
do
rsync -v -r -l -H -p -g -t -S -e ssh –exclude “.svn” –delete /home/admin/hadoop-installed/conf/ admin@$DEST:/home/admin/hadoop-installed/conf/
rsync -v -r -l -H -p -g -t -S -e ssh –delete /home/admin/hadoop-installed/hadoop/ alisoft@$DEST:/home/admin/hadoop-ins
talled/hadoop/
done
exit 0
[/quote]