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在Centos7中安装Hadoop实战

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更新limits.conf

[root@master ~]# vim /etc/security/limits.conf 

hdfs            -       nofile          32768
hbase           -       nofile          32768

hdfs            soft    nproc           32000
hdfs            hard    nproc           32000

hbase           soft    nproc           32000
hbase           hard    nproc           32000

参考

更新hostname

[root@master ~]# hostnamectl set-hostname master
[root@master ~]# hostname
[root@master ~]# vim /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

192.168.10.68 master.hadoop.lan

创建hadoop用户

[root@localhost ~]# useradd -m hadoop -s /bin/bash
[root@localhost ~]# passwd hadoop
[root@localhost ~]# visudo

## Allow root to run any commands anywhere
root    ALL=(ALL)       ALL
hadoop  ALL=(ALL)       ALL

安装配置Jdk和JAVA_HOME

参考: Centos7安装jdk实战

安装配置Hadoop

下载Hadoop 2.7.3 binary

[hadoop@localhost ~]$ cd /usr/local/
[hadoop@localhost local]$ sudo tar -zxvf hadoop-2.7.3.tar.gz -C /usr/local/
[hadoop@localhost local]$ sudo mv ./hadoop-2.7.3 ./hadoop
[hadoop@localhost local]$ sudo chown -R hadoop ./hadoop
[hadoop@localhost local]$ cd hadoop/
[hadoop@localhost hadoop]$ ./bin/hadoop version
[hadoop@localhost hadoop]$ vim ~/.bashrc

# User specific aliases and functions
export HADOOP_HOME=/usr/local/hadoop
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native

export JAVA_HOME=/usr/java/jdk1.8.0_112
export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin

export PATH=$PATH:/usr/local/hadoop/sbin:/usr/local/hadoop/bin

[hadoop@localhost hadoop]$ source ~/.bashrc

Hadoop 附带了丰富的例子

[hadoop@localhost hadoop]$ ./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.3.jar

grep 例子

我们将 input 文件夹中的所有文件作为输入,筛选当中符合正则表达式 dfs[a-z.]+ 的单词并统计出现的次数,最后输出结果到 output 文件夹中。

[hadoop@localhost hadoop]$ ./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.3.jar grep ./input ./output 'dfs[a-z.]+'
[hadoop@localhost hadoop]$ cat ./output/*
[hadoop@localhost hadoop]$ rm -r ./output

Hadoop伪分布式配置

Update core-site.xml

[hadoop@localhost hadoop]$ cp ./etc/hadoop/core-site.xml ./etc/hadoop/core-site.xml.bak
[hadoop@localhost hadoop]$ vim ./etc/hadoop/core-site.xml

[BEFORE]

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
</configuration>

[AFTER]

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>


<configuration>
    <property>
        <name>hadoop.tmp.dir</name>
        <value>file:/usr/local/hadoop/tmp</value>
        <description>Abase for other temporary directories.</description>
    </property>
    <property>
        <name>fs.defaultFS</name>
        <value>hdfs://master.hadoop.lan:9000</value>
    </property>
</configuration>

Update hdfs-site.xml

[hadoop@localhost hadoop]$ cp ./etc/hadoop/hdfs-site.xml ./etc/hadoop/hdfs-site.xml.bak
[hadoop@localhost hadoop]$ vim ./etc/hadoop/hdfs-site.xml

[BEFORE]

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<configuration>

</configuration>

[AFTER]

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<configuration>
    <property>
        <name>dfs.replication</name>
        <value>1</value>
    </property>
    <property>
        <name>dfs.namenode.name.dir</name>
        <value>file:/usr/local/hadoop/tmp/dfs/name</value>
    </property>
    <property>
        <name>dfs.datanode.data.dir</name>
        <value>file:/usr/local/hadoop/tmp/dfs/data</value>
    </property>
</configuration>

执行 NameNode 的格式化

[hadoop@localhost hadoop]$ ./bin/hdfs namenode -format

开启 NameNode 和 DataNode 守护进程

[hadoop@localhost hadoop]$ ./sbin/start-dfs.sh

查看是否启动成功

[hadoop@localhost hadoop]$ jps

配置防火墙

[hadoop@localhost ~]$ sudo vim /etc/sysconfig/iptables
-A INPUT -p tcp -m state --state NEW -m tcp --dport 9000 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 50070 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 50010 -j ACCEPT
[hadoop@localhost ~]$ service iptables restart

通过浏览器访问

http://localhost:50070

运行Hadoop伪分布式实例

运行程序

[hadoop@localhost hadoop]$ ./bin/hdfs dfs -mkdir -p /user/hadoop
[hadoop@localhost hadoop]$ ./bin/hdfs dfs -mkdir input
[hadoop@localhost hadoop]$ ./bin/hdfs dfs -put ./etc/hadoop/*.xml input
[hadoop@localhost hadoop]$ ./bin/hdfs dfs -ls input
[hadoop@localhost hadoop]$ ./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar grep input output 'dfs[a-z.]+'
[hadoop@localhost hadoop]$ ./bin/hdfs dfs -cat output/*

取结果到本地

[hadoop@localhost hadoop]$ rm -r ./output
[hadoop@localhost hadoop]$ ./bin/hdfs dfs -get output ./output
[hadoop@localhost hadoop]$ cat ./output/*

[hadoop@localhost hadoop]$ ./bin/hdfs dfs -ls
[hadoop@localhost hadoop]$ ./bin/hdfs dfs -rm -r output

常用命令

[hadoop@localhost hadoop]$ ./sbin/stop-dfs.sh
[hadoop@localhost hadoop]$ rm -r ./tmp
[hadoop@localhost hadoop]$ ./bin/hdfs namenode -format
[hadoop@localhost hadoop]$ ./sbin/start-dfs.sh 

最终,总结下来解决办法大概有三种:

1、在系统的环境变量或java JVM变量里面添加HADOOP_USER_NAME,这个值具体等于多少看自己的情况,以后会运行HADOOP上的Linux的用户名。(修改完重启eclipse,不然可能不生效)

2、将当前系统的帐号修改为hadoop

3、使用HDFS的命令行接口修改相应目录的权限,hadoop fs -chmod 777 /user,后面的/user是要上传文件的路径,不同的情况可能不一样,比如要上传的文件路径为hdfs://namenode/user/xxx.doc,则这样的修改可以,如果要上传的文件路径为hdfs://namenode/java/xxx.doc,则要修改的为hadoop fs -chmod 777 /java或者hadoop fs -chmod 777 /,java的那个需要先在HDFS里面建立Java目录,后面的这个是为根目录调整权限。

我喜欢第一个方法。

其他

https://github.com/srccodes/hadoop-common-2.2.0-bin

http://www.huqiwen.com/2013/07/18/hdfs-permission-denied/


Exception in thread "main" org.apache.hadoop.security.AccessControlException: Permission denied: user=baoguo, access=WRITE, inode="/d100":hadoop:supergroup:drwxr-xr-x

http://blog.csdn.net/xw13106209/article/details/6866072

Name node is in safe mode
bin/hadoop dfsadmin -safemode leave 

用户可以通过dfsadmin -safemode value 来操作安全模式,参数value的说明如下:
enter - 进入安全模式
leave - 强制NameNode离开安全模式
get - 返回安全模式是否开启的信息
wait - 等待,一直到安全模式结束。

参考资料

  1. HDFS简单入门
  2. hadoop集群搭建
  3. Hadoop 集群搭建
  4. 安装并运行hadoop
  5. Ubuntu 14.04下安装JDK8
  6. HDFS主要特性和体系结构
  7. Hadoop安装教程_单机/伪分布式配置_Hadoop2.6.0/Ubuntu14.04
  8. Hadoop集群(第5期)_Hadoop安装配置
  9. Hadoop之——HDFS操作实例
  10. hadoop集群默认配置和常用配置
  11. hadoop http address绑定内网地址
  12. Hadoop上传文件报错解决方法

声明: 本文采用 BY-NC-SA 授权。转载请注明转自: Ding Bao Guo