编译:
0. 环境准备
maven（下载安装，配置环境变量，修改sitting.xml加阿里云镜像）
gcc-c++
zlib-devel
autoconf
automake
libtool
通过yum安装即可，yum -y install gcc-c++ lzo-devel zlib-devel autoconf automake libtool
1. 下载、安装并编译LZO
wget http://www.oberhumer.com/opensource/lzo/download/lzo-2.10.tar.gz
tar -zxvf lzo-2.10.tar.gz
cd lzo-2.10
./configure -prefix=/usr/local/hadoop/lzo/
make
make install
2. 编译hadoop-lzo源码
2.1 下载hadoop-lzo的源码，下载地址：https://github.com/twitter/hadoop-lzo/archive/master.zip
2.2 解压之后，修改pom.xml
<hadoop.current.version>2.7.2</hadoop.current.version>
2.3 声明两个临时环境变量
export C_INCLUDE_PATH=/usr/local/hadoop/lzo/include
export LIBRARY_PATH=/usr/local/hadoop/lzo/lib
2.4 编译
进入hadoop-lzo-master，执行maven编译命令
mvn package -Dmaven.test.skip=true
2.5 进入target，将hadoop-lzo-0.4.21-SNAPSHOT.jar放到hadoop的classpath下，如${HADOOP_HOME}/share/hadoop/common
2.6 修改core-site.xml增加配置支持LZO压缩
<configuration>
<property>
<name>io.compression.codecs</name>
<value>
org.apache.hadoop.io.compress.GzipCodec,
org.apache.hadoop.io.compress.DefaultCodec,
org.apache.hadoop.io.compress.BZip2Codec,
org.apache.hadoop.io.compress.SnappyCodec,
com.hadoop.compression.lzo.LzoCodec,
com.hadoop.compression.lzo.LzopCodec
</value>
</property>
<property>
<name>io.compression.codec.lzo.class</name>
<value>com.hadoop.compression.lzo.LzoCodec</value>
</property>
</configuration>
<mirror>
<id>nexus-aliyun</id>
<mirrorOf>*</mirrorOf>
<name>Nexus aliyun</name>
<url>http://maven.aliyun.com/nexus/content/groups/public</url>
</mirror>
配置lzo：
1）先下载lzo的jar项目
https://github.com/twitter/hadoop-lzo/archive/master.zip
2）下载后的文件名是hadoop-lzo-master，它是一个zip格式的压缩包，先进行解压，然后用maven编译。生成hadoop-lzo-0.4.20.jar。
3）将编译好后的hadoop-lzo-0.4.20.jar 放入hadoop-2.7.2/share/hadoop/common/
[atguigu@hadoop102 common]$ pwd
/opt/module/hadoop-2.7.2/share/hadoop/common
[atguigu@hadoop102 common]$ ls
hadoop-lzo-0.4.20.jar
4）同步hadoop-lzo-0.4.20.jar到hadoop103、hadoop104
[atguigu@hadoop102 common]$ xsync hadoop-lzo-0.4.20.jar
5）core-site.xml增加配置支持LZO压缩
<?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?> <configuration> <property> <name>io.compression.codecs</name> <value> org.apache.hadoop.io.compress.GzipCodec, org.apache.hadoop.io.compress.DefaultCodec, org.apache.hadoop.io.compress.BZip2Codec, org.apache.hadoop.io.compress.SnappyCodec, com.hadoop.compression.lzo.LzoCodec, com.hadoop.compression.lzo.LzopCodec </value> </property> <property> <name>io.compression.codec.lzo.class</name> <value>com.hadoop.compression.lzo.LzoCodec</value> </property> </configuration>
5）同步core-site.xml到hadoop103、hadoop104
[atguigu@hadoop102 hadoop]$ xsync core-site.xml
6）启动及查看集群
[atguigu@hadoop102 hadoop-2.7.2]$ sbin/start-dfs.sh
[atguigu@hadoop103 hadoop-2.7.2]$ sbin/start-yarn.sh
（1）web和进程查看
Ø Web查看：http://hadoop102:50070
Ø 进程查看：jps查看各个节点状态。
（2）当启动发生错误的时候：
Ø 查看日志：/home/atguigu/module/hadoop-2.7.2/logs
Ø 如果进入安全模式，可以通过hdfs dfsadmin -safemode leave
Ø 停止所有进程，删除data和log文件夹，然后hdfs namenode -format 来格式化
hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.2.jar wordcount -Dmapreduce.output.fileoutputformat.compress=true -Dmapreduce.output.fileoutputformat.compress.codec=com.hadoop.compression.lzo.LzopCodec /input /output //测试
