hadoop 2.8.0在centos7 搭建（初入大数据）

第一步：

①准备三台虚拟机使用 VMware Workstation工具

配置过程参考 https://blog.csdn.net/pucao_cug/article/details/71229416

配置好使用工具CRT 连接

②更改主机名

192.168.220.128 s1

192.168.220.128 s2

192.168.220.128 s3

---------------三台都改---------------------

[root@s1 ~]# hostname        //查看主机名
sss
[root@s1 ~]# hostname s1        //修改主机名
[root@s1 ~]# hostname
s1

修改这3台机器的/etc/hosts文件，在文件中添加以下内容

192.168.220.128  s1

192.168.220.128  s2

192.168.220.128  s3

③将这三台虚拟机配置设置免密登陆

#在192.168.220.128上生产一对钥匙

                             ssh-keygen -t rsa

                             #将公钥拷贝到其他节点，包括自己

                             ssh-copy-id 192.168.220.128

                             ssh-copy-id 192.168.220.129

                             ssh-copy-id 192.168.220.130

我这里只这在 192.168.220.128 节点上免密登陆另外两台节点

配置好后输入 ssh 命令如下第一次登陆会进行一次交互输入 yes即可

退出输 exit 命令

第二步：

①给三台机器安装配置jdk 我用jdk8 参考此链接

http://blog.csdn.net/pucao_cug/article/details/68948639

②安装hadoop

下载地址：http://www.apache.org/dyn/closer.cgi/hadoop/common/hadoop-2.8.0/hadoop-2.8.0.tar.gz

3台机器上都需要下面所讲的步骤。

*****在opt目录下新建一个名为hadoop的目录，并将下载得到的hadoop-2.8.0.tar上传到该目录下

使用下面命令解压

tar -zxvf  ************tar.gz

********在/root目录下新建几个目录，复制粘贴执行下面的命令：

mkdir  /root/hadoop
mkdir  /root/hadoop/tmp
mkdir  /root/hadoop/var
mkdir  /root/hadoop/dfs
mkdir  /root/hadoop/dfs/name
mkdir  /root/hadoop/dfs/data

********修改配置文件 /opt/hadoop/hadoop-2.8.0/etc/hadoop 目录下的

修改core-site.xml

<configuration>
<property>
        <name>hadoop.tmp.dir</name>
        <value>/root/hadoop/tmp</value>
        <description>Abase for other temporary directories.</description>
   </property>
   <property>
        <name>fs.default.name</name>
        <value>hdfs://s1:9000</value>
   </property>
</configuration>

修改 hadoop-env.sh

export JAVA_HOME= ${JAVA_HOME

将${JAVA_HOME} 修改成自己jdk路径

我这里是

export JAVA_HOME=/opt/java/jdk1.8.0_60

修改 hdfs-site.xml

<configuration>
<property>
   <name>dfs.name.dir</name>
   <value>/root/hadoop/dfs/name</value>
   <description>Path on the local filesystem where theNameNode stores the namespace and transactions logs persistently.</description>
</property>
<property>
   <name>dfs.data.dir</name>
   <value>/root/hadoop/dfs/data</value>
   <description>Comma separated list of paths on the localfilesystem of a DataNode where it should store its blocks.</description>
</property>
<property>
   <name>dfs.replication</name>
   <value>2</value>
</property>
</configuration>

修改mapred-site.xml

<configuration>
<property>
  
 <name>mapred.job.tracker</name>
  
 <value>s1:49001</value>
</property>
<property>
      <name>mapred.local.dir</name>
       <value>/root/hadoop/var</value>
</property>

<property>
       <name>mapreduce.framework.name</name>
       <value>yarn</value>
</property>
</configuration>

修改slaves 将localhost删除

s2
s3

修改yarn-site.xml

<configuration>
<property>
        <name>yarn.resourcemanager.hostname</name>
        <value>s1</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>
   <property>
        <name>yarn.scheduler.maximum-allocation-mb</name>
        <value>2048</value>
        <discription>每个节点可用内存,单位MB,默认8182MB</discription>
   </property>
   <property>
        <name>yarn.nodemanager.vmem-pmem-ratio</name>
        <value>2.1</value>
   </property>
   <property>
        <name>yarn.nodemanager.resource.memory-mb</name>
        <value>4096</value>
</property>

   <property>
        <name>yarn.nodemanager.vmem-check-enabled</name>
        <value>false</value>
</property>
</configuration>

第三步：启动hadoop

启动之前配置一下 etc/profile 文件

将配置一下环境变量