hadoop集群搭建（hdfs）

　　（搭建hadoop集群的前提是服务器已成功安装jdk以及服务器之间已设置免密码登录，服务器之间的免密码登录可参考《linux服务器间ssh免密码登录》）

1、下载hadoop安装包

　　wget http://mirror.bit.edu.cn/apache/hadoop/common/hadoop-3.0.0/hadoop-3.0.0-src.tar.gz

2、解压安装包

　　tar zxvf hadoop-3.0.0-src.tar.gz

3、配置hadoop的环境变量

　　vi /etc/profile（三台机器）

　　增加以下配置

#Hadoop 3.0
export HADOOP_PREFIX=/home/hadoop/hadoop-3.0.0
export PATH=$PATH:$HADOOP_PREFIX/bin:$HADOOP_PREFIX/sbin

export HADOOP_COMMON_HOME=$HADOOP_PREFIX 
export HADOOP_HDFS_HOME=$HADOOP_PREFIX 
export HADOOP_MAPRED_HOME=$HADOOP_PREFIX
export HADOOP_YARN_HOME=$HADOOP_PREFIX 

export HADOOP_INSTALL=$HADOOP_PREFIX
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_PREFIX/lib/native 
export HADOOP_CONF_DIR=$HADOOP_PREFIX 
export HADOOP_PREFIX=$HADOOP_PREFIX 
export HADOOP_LIBEXEC_DIR=$HADOOP_PREFIX/libexec 
export JAVA_LIBRARY_PATH=$HADOOP_PREFIX/lib/native:$JAVA_LIBRARY_PATH 
export HADOOP_CONF_DIR=$HADOOP_PREFIX/etc/hadoop

　　　　source /etc/profile

4、修改配置文件

　　vi /etc/hosts(三台机器)

　　　　增加以下配置

10.9.1.101   node101
10.9.1.102   node102
10.9.1.103   node103

　　vi /home/hadoop/hadoop-3.0.0/etc/hadoop/core-site.xml（三台机器）

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->

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

<configuration>
  <property>
     <name>fs.defaultFS</name>
     <value>hdfs://node101:9000</value> 
     <description>HDFS的URI，文件系统://namenode标识:端口</description>
  </property>
  <property>
     <name>hadoop.tmp.dir</name>
     <value>/opt/hadoop</value>
     <description>namenode上传到hadoop的临时文件夹</description>
  </property>
  <property>
       <name>fs.checkpoint.period</name>
       <value>3600</value>
       <description>用来设置检查点备份日志的最长时间</description>
  </property>
</configuration>

　　vi /home/hadoop/hadoop-3.0.0/etc/hadoop/hdfs-site.xml（三台机器）

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->

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

<configuration>
 <property>
   <name>dfs.replication</name>
   <value>3</value> 
   <description>副本个数，默认配置是3，应小于datanode机器数量</description>
 </property>
 <property>
    <name>dfs.name.dir</name>
    <value>/home/hadoop/hadoop-3.0.0/hdfs/name</value>
    <description>datanode上存储hdfs名字空间元数据</description>
  </property>
 <property>
    <name>dfs.data.dir</name>
    <value>/home/hadoop/hadoop-3.0.0/hdfs/data</value>
    <description>datanode上数据块的物理存储位置</description>
 </property>
</configuration>