1. SSH
参考博文：[Hadoop]SSH免密码登录以及失败解决方案（http://blog.csdn.net/sunnyyoona/article/details/51689041#t1）
2. 下载
（1）直接从官网上下载 http://hadoop.apache.org/releases.html
（2）使用命令行下载：
xiaosi@yoona:~$ wget http://mirrors.hust.edu.cn/apache/hadoop/common/hadoop-2.7.3/hadoop-2.7.3.tar.gz--2016-06-16 08:40:07-- http://mirrors.hust.edu.cn/apache/hadoop/common/hadoop-2.7.3/hadoop-2.7.3.tar.gz正在解析主机 mirrors.hust.edu.cn (mirrors.hust.edu.cn)... 202.114.18.160正在连接 mirrors.hust.edu.cn (mirrors.hust.edu.cn)|202.114.18.160|:80... 已连接。已发出 HTTP 请求，正在等待回应... 200 OK长度： 196015975 (187M) [application/octet-stream]正在保存至: “hadoop-2.6.4.tar.gz”
3. 解压缩Hadoop包
解压位于根目录/文件夹下的hadoop-2.7.3.tar.gz到~/opt文件夹下
xiaosi@yoona:~$ tar -zxvf hadoop-2.7.3.tar.gz -C opt/
4. 配置
配置文件都位于安装目录下的 /etc/hadoop文件夹下：
xiaosi@yoona:~/opt/hadoop-2.7.3/etc/hadoop$ lscapacity-scheduler.xml hadoop-env.sh httpfs-log4j.properties log4j.properties mapred-site.xml.templateconfiguration.xsl hadoop-metrics2.properties httpfs-signature.secret log4j.properties slavescontainer-executor.cfg hadoop-metrics.properties httpfs-site.xml mapred-env.cmd ssl-client.xml.examplecore-site.xml hadoop-policy.xml kms-acls.xml mapred-env.sh ssl-server.xml.examplecore-site.xml hdfs-site.xml kms-env.sh mapred-queues.xml.template yarn-env.cmdhadoop-env.cmd hdfs-site.xml kms-log4j.properties mapred-site.xml yarn-env.shhadoop-env.sh httpfs-env.sh kms-site.xml mapred-site.xml yarn-site.xml
Hadoop的各个组件均可利用XML文件进行配置。core-site.xml文件用于配置Common组件的属性，hdfs-site.xml文件用于配置HDFS属性，而mapred-site.xml文件则用于配置MapReduce属性。
备注：
Hadoop早期版本采用一个配置文件hadoop-site.xml来配置Common，HDFS和MapReduce组件。从0.20.0版本开始该文件以分为三，各对应一个组件。
4.1 配置core-site.xml
core-site.xml 配置如下：
<?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 athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed 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 andlimitations under the License. See accompanying LICENSE file.--><!-- Put site-specific property overrides in this file. --><configuration><property><name>hadoop.tmp.dir</name><value>/home/${user.name}/tmp/hadoop</value><description>Abase for other temporary directories.</description></property><property><name>fs.defaultFS</name><value>hdfs://localhost:9000</value></property><property><name>hadoop.proxyuser.xiaosi.hosts</name><value>*</value><description>The superuser can connect only from host1 and host2 to impersonate a user</description></property><property><name>hadoop.proxyuser.xiaosi.groups</name><value>*</value><description>Allow the superuser oozie to impersonate any members of the group group1 and group2</description></property></configuration>
4.2 配置hdfs-site.xml
hdfs-site.xml配置如下：
<?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 athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed 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 andlimitations under the License. See accompanying LICENSE file.--><!-- Put site-specific property overrides in this file. --><configuration><property><name>dfs.replication</name><value>1</value></property><property><name>dfs.namenode.name.dir</name><value>file:/home/xiaosi/tmp/hadoop/dfs/name</value></property><property><name>dfs.datanode.data.dir</name><value>file:/home/xiaosi/tmp/hadoop/dfs/data</value></property></configuration>
4.3 配置 mapred-site.xml
mapred-site.xml配置如下：
<?xml version="1.0"?><?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 athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed 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 andlimitations under the License. See accompanying LICENSE file.--><!-- Put site-specific property overrides in this file. --><configuration><property><name>mapred.job.tracker</name><value>localhost:9001</value></property></configuration>
运行Hadoop的时候可能会找不到jdk，需要我们修改hadoop.env.sh脚本文件，唯一需要修改的环境变量就是JAVE_HOME，其他选项都是可选的：
export JAVA_HOME=/home/xiaosi/opt/jdk-1.8.0
5. 运行
5.1 初始化HDFS系统
在配置完成后，运行hadoop前，要初始化HDFS系统，在bin/目录下执行如下命令：
xiaosi@yoona:~/opt/hadoop-2.7.3$ ./bin/hdfs namenode -format
5.2 启动
开启NameNode和DataNode守护进程：
xiaosi@yoona:~/opt/hadoop-2.7.3$ ./sbin/start-dfs.shStarting namenodes on [localhost]localhost: starting namenode, logging to /home/xiaosi/opt/hadoop-2.7.3/logs/hadoop-xiaosi-namenode-yoona.outlocalhost: starting datanode, logging to /home/xiaosi/opt/hadoop-2.7.3/logs/hadoop-xiaosi-datanode-yoona.outStarting secondary namenodes [0.0.0.0]0.0.0.0: starting secondarynamenode, logging to /home/xiaosi/opt/hadoop-2.7.3/logs/hadoop-xiaosi-secondarynamenode-yoona.out
通过jps命令查看namenode和datanode是否已经启动起来：
xiaosi@yoona:~/opt/hadoop-2.7.3$ jps13400 SecondaryNameNode13035 NameNode13197 DataNode13535 Jps
从启动日志我们可以知道，日志信息存储在
hadoop-2.7.3/logs/目录下，如果启动过程中有任何问题，可以通过查看日志来确认问题原因。
