注意：安装之前最好删除hadoop-2.6.0/dfs/data下的所有文件，避免出现各种问题。尤其安装包不是官方现下载的。
需要重新编译的教程：http://blog.****.net/ggz631047367/article/details/42460589
在Ubuntu下创建hadoop用户组和用户
hadoop的管理员最好就是以后要登录桌面环境运行eclipse的用户，否则后面会有拒绝读写的问题出现。当然不是也有办法办法解决。
1. 创建hadoop用户组;
sudo addgroup hadoop2. 创建hadoop用户;
sudo adduser -ingroup hadoop hadoop3. 给hadoop用户添加权限，打开/etc/sudoers文件;
sudo gedit /etc/sudoers
在root ALL=(ALL:ALL) ALL下添加hadoop ALL=(ALL:ALL) ALL.
在Ubuntu下安装JDK
具体见：http://blog.****.net/ggz631047367/article/details/42366687
//JAVA_HOME=/usr/lib/jvm/jdk1.8.0_25
安装ssh服务
sudo apt-get install ssh openssh-server
建立ssh无密码登录本机
切换到hadoop用户，执行以下命令：
su - hadoopssh生成密钥有rsa和dsa两种生成方式，默认情况下采用rsa方式。
1. 创建ssh-key，，这里我们采用rsa方式;
ssh-keygen -t rsa -P "" （注：回车后会在~/.ssh/下生成两个文件：id_rsa和id_rsa.pub这两个文件是成对出现的）
2. 进入~/.ssh/目录下，将id_rsa.pub追加到authorized_keys授权文件中，开始是没有authorized_keys文件的;
cd ~/.ssh cat id_rsa.pub >> authorized_keys （完成后就可以无密码登录本机了。）
3. 登录localhost;
ssh localhost
4. 执行退出命令;
exit
安装hadoop
下载地址：http://apache.fayea.com/hadoop/common/stable/hadoop-2.6.0.tar.gz
因多次修改，可能会有Hadoop实际路径和配置文件中Hadoop路径不同，可能会产生错误
1. 把hadoop解压到/usr/local下:
sudo tar -zxvf hadoop-2.6.0.tar.gz sudo mv hadoop-2.6.0 /usr/local/hadoop sudo chmod -R 775 /usr/local/hadoop sudo chown -R hadoop:hadoop /usr/local/hadoop //否则ssh会拒绝访问2.配置
修改bashrc的配置：
sudo gedit ~/.bashrc
在文件末尾添加：
#HADOOP VARIABLES START export JAVA_HOME=/usr/lib/jvm/jdk1.8.0_25 export HADOOP_INSTALL=/usr/local/hadoop export PATH=$PATH:$HADOOP_INSTALL/bin export PATH=$PATH:$JAVA_HOME/bin export PATH=$PATH:$HADOOP_INSTALL/sbin export HADOOP_MAPRED_HOME=$HADOOP_INSTALL export HADOOP_COMMON_HOME=$HADOOP_INSTALL export HADOOP_HDFS_HOME=$HADOOP_INSTALL export YARN_HOME=$HADOOP_INSTALL export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_INSTALL/lib/native export HADOOP_OPTS="-Djava.library.path=$HADOOP_INSTALL/lib" #HADOOP VARIABLES END如果不知道JAVA_HOME可以通过命令获得：update-alternatives --config java目录取到java根目录即可。
执行下面命令使改动生效：
source ~/.bashrc修改hadoop-env.sh的配置：
sudo gedit /usr/local/hadoop/etc/hadoop/hadoop-env.sh
找到JAVA_HOME改为上面的值。
测试
- 通过执行hadoop自带实例WordCount验证是否安装成功
/usr/local/hadoop路径下创建input文件夹
mkdir input cp README.txt input在hadoop目录下执行WordCount：bin/hadoop jar share/hadoop/mapreduce/sources/hadoop-mapreduce-examples-2.6.0-sources.jar org.apache.hadoop.examples.WordCount input output
Hadoop伪分布式配置
sudo gedit /usr/local/hadoop/etc/hadoop/core-site.xml
<configuration> <property> <name>hadoop.tmp.dir</name> <value>/usr/local/hadoop/tmp</value> <description>Abase for other temporary directories.</description> </property> <property> <name>fs.defaultFS</name> <value>hdfs://localhost:9000</value> </property> </configuration>sudo gedit /usr/local/hadoop/etc/hadoop/yarn-site.xml
<property> <name>yarn.resourcemanager.hostname</name> <value>master</value> </property> <property> <description>The address of the applications manager interface in the RM.</description> <name>yarn.resourcemanager.address</name> <value>${yarn.resourcemanager.hostname}:8032</value> </property> <property> <description>The address of the scheduler interface.</description> <name>yarn.resourcemanager.scheduler.address</name> <value>${yarn.resourcemanager.hostname}:8030</value> </property> <property> <description>The http address of the RM web application.</description> <name>yarn.resourcemanager.webapp.address</name> <value>${yarn.resourcemanager.hostname}:8088</value> </property> <property> <description>The https adddress of the RM web application.</description> <name>yarn.resourcemanager.webapp.https.address</name> <value>${yarn.resourcemanager.hostname}:8090</value> </property> <property> <name>yarn.resourcemanager.resource-tracker.address</name> <value>${yarn.resourcemanager.hostname}:8031</value> </property> <property> <description>The address of the RM admin interface.</description> <name>yarn.resourcemanager.admin.address</name> <value>${yarn.resourcemanager.hostname}:8033</value> </property> <property> <name>yarn.nodemanager.aux-services</name> <value>mapreduce_shuffle</value> </property>
sudo gedit /usr/local/Hadoop/etc/Hadoop/mapred-site.xml //伪分布式不用配
<property> <name>mapreduce.framework.name</name> <value>yarn</value> </property> <property> <name>mapreduce.jobhistory.address</name> <value>master:10020</value> <description>MapReduce JobHistory Server IPC host:port</description> </property> <property> <name>mapreduce.jobhistory.webapp.address</name> <value>master:19888</value> <description>MapReduce JobHistory Server Web UI host:port</description> </property>
sudo gedit /usr/local/hadoop/etc/hadoop/hdfs-site.xml
<configuration> <property> <name>dfs.replication</name> <value>1</value> </property> <property> <name>dfs.namenode.name.dir</name> <value>file:/usr/local/hadoop/dfs/name</value> </property> <property> <name>dfs.datanode.data.dir</name> <value>file:/usr/local/hadoop/dfs/data</value> </property> <property> //这个属性节点是为了防止后面eclopse存在拒绝读写设置的 <name>dfs.permissions</name> <value>false</value> </property> </configuration>sudo gedit /usr/local/hadoop/etc/hadoop/
masters 添加：localhostsudo gedit /usr/local/hadoop/etc/hadoop/
slaves添加：localhost
关于配置的一点说明：上面只要配置 fs.defaultFS 和 dfs.replication 就可以运行，不过有个说法是如没有配置 hadoop.tmp.dir 参数，此时 Hadoop 默认的使用的临时目录为 /tmp/hadoo-hadoop，而这个目录在每次重启后都会被干掉，必须重新执行 format 才行（未验证），所以伪分布式配置中最好还是设置一下。
配置完成后，首先在 Hadoop 目录下创建所需的临时目录：
cd /usr/local/hadoop mkdir tmp dfs dfs/name dfs/data
修改pid目录位置（可以不做）
vi hadoop-env.shexport HADOOP_PID_DIR=/usr/local/hadoop-2.6.0/pidvi mapred-env.shexport HADOOP_MAPRED_PID_DIR=/usr/local/hadoop-2.6.0/pidyarn-env.shexport YARN_PID_DIR=/usr/local/hadoop-2.6.0/pid
接着初始化文件系统HDFS。
bin/hdfs namenode -format //每次执行此命令要把dfs/data/文件清空成功的话，最后的提示如下，Exitting with status 0表示成功，Exitting with status 1:则是出错。
sbin/start-dfs.sh sbin/start-yarn.sh开启Jobhistory
sbin/mr-jobhistory-daemon.sh start historyserver <a target=_blank href="http://master:19888/">http://master:19888/</a>
Unable to load native-hadoop library for your platform这个提示,解决方式：
1、重新编译源码后将新的lib/native替换到集群中原来的lib/native
2、修改hadoop-env.sh ，增加
export HADOOP_OPTS="-Djava.library.path=$HADOOP_PREFIX/lib:$HADOOP_PREFIX/lib/native"Namenode information:http://localhost:50070来查看Hadoop的信息。
All Applications：http://http://2xx.81.8x.1xx:8088/，将其中的2xx.81.8x.1xx替换为你的实际IP地址。
运行例子：
1.先在hdfs上建个文件夹 bin/hdfs dfs -mkdir -p /user/ha1/input
bin/hdfs dfs -mkdir -p /user/ha1/output
2.上传一些文件：bin/hdfs dfs -put etc/hadoop/ /user/ha1/input 把etc/hadoop文件上传到hdfs的/user/ha1/input中
3.执行指令
bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.0.jar grep /user/ha1/input/hadoop /user/ha1/output/temp 'dfs[a-z.]+'
错误1：
WARN hdfs.DFSClient: DataStreamer Exception
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /user/ha1/input/hadoop/yarn-env.sh._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1). There are 0 datanode(s) running and no node(s) are excluded in this operation.//删除dfs/data/目录所有文件，关闭所有服务重新执行bin/hdfs namenode -format以及1，2步骤
错误2：
org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.SafeModeException): Cannot delete /user/root/grep-temp-23493900. Name node is in safe mode.
The reported blocks 188 has reached the threshold 0.9990 of total blocks 188. The number of live datanodes 2 has reached the minimum number 0. In safe mode extension. Safe mode will be turned off automatically in 10 seconds.
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkNameNodeSafeMode(FSNamesystem.java:1364)操作太快，未退出安全模式，等退出安全模式
4.查看结果
bin/hdfs dfs -cat /user/ha1/output/temp/*
8 dfs.audit.logger 4 dfs.class 3 dfs.server.namenode. 2 dfs.audit.log.maxbackupindex 2 dfs.period 2 dfs.audit.log.maxfilesize 1 dfsmetrics.log 1 dfsadmin 1 dfs.servers 1 dfs.replication 1 dfs.file 1 dfs.datanode.data.dir 1 dfs.namenode.name.dir终止一个job：
hadoop job -kill job_1447903602796_0001