Hadoop的安装和配置，Hadoop集群搭建

一，Hadoop的安装：

vim /etc/hosts
172.25.38.7    server7
useradd hadoop
su - hadoop
pwd 
/home/hadoop
tar zxf hadoop-2.7.3.tar.gz
 tar zxf jdk-7u79-linux-x64.tar.gz 
 ln -s jdk1.7.0_79/ jdk
ln -s hadoop-2.7.3 hadoop
vim /home/hadoop/.bash_profile 
10 PATH=$PATH:$HOME/bin:/home/hadoop/jdk/bin

 vim hadoop/etc/hadoop/hadoop-env.sh   
 25 export JAVA_HOME=/home/hadoop/jdk

测试使用Hadoop自带的wordcount：

cd /home/hadoop/hadoop
mkdir input
cp etc/hadoop/* input/

bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.3.jar wordcount input output
cd output
hadoop@server7 output]$ ls
part-r-00000  _SUCCESS              #对input执行mapreduce的结果
cat part-r-00000        #可以看见wordcount功能已经完成了mapreduce任务；
!=      3
""      6
"".     4
"$HADOOP_CLASSPATH"     1
"$JAVA_HOME"    2
"$YARN_HEAPSIZE"        1
"$YARN_LOGFILE" 1
"$YARN_LOG_DIR" 1
"$YARN_POLICYFILE"      1
"*"     18
"AS     24
"Error: 1
"License");     24
"alice,bob      18
"console"       1
"dfs"   3
"hadoop.root.logger".   1
"jks".  4
"jvm"   3
"mapred"        3
"rpc"   3
"run    1
"ugi"   3
"x"     1

单节点集群：NN DN SNN在一台主机上：

cd /home/hadoop/hadoop/etc/hadoop
vim core-site.xml19 <configuration>
 20 <property>
 21         <name>fs.defaultFSname>
 22                 <value>hdfs://172.25.38.7:9000value>
 23                     property>
 24 configuration>


vim hdfs-site.xml
19 <configuration>
 20 <property>
 21         <name>dfs.replicationname>
 22                 <value>1value>        #此时数据块仅仅保存一份，默认保存三份
 23                     property>
 24 configuration>

vim /home/hadoop/hadoop/etc/hadoop/slaves 
172.25.38.7

ssh-keygen
ssh-copy-id 172.25.38.7
ssh-copy-id server7

bin/hdfs namenode -format
/home/hadoop/hadoop/sbin/start-dfs.sh 
jps

Hadoop集群搭建：

server7:namenode，SecondaryNameNode
server8,server9:datanode
1,配置集群节点时间同步：设置集群节点同步主机的时间：

主机上：vim /etc/chrony.conf
7 server time1.aliyun.com  iburst    #设置主机同步阿里云的时间
23 allow 172.25.38/24           #允许同步的主机网段

server7，server8，server9上：

yum install -y ntp
 vim /etc/ntp.conf 22 server 172.25.38.250 iburst      设置集群节点同步主机的时间
 /etc/init.d/ntpd start

2，配置nfs共享配置：
server7上：

yum install -y nfs-utils
/etc/init.d/rpcbind  start
/etc/init.d/nfs start
/home/hadoop    *(rw,anonuid=500,anongid=500)
exportfs -rv

server8,server9上：

useradd hadoop
yum install -y nfs-utils
/etc/init.d/rpcbind  start
/etc/init.d/nfs start
showmount -e 172.25.38.7
mount 172.25.38.7:/home/hadoop/ /home/hadoop/
vim /home/hadoop/.bash_profile 

PATH=$PATH:$HOME/bin:/home/hadoop/jdk/bin

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