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前言

操作前需要准备:

  1. 虚拟机镜像:CentOS-6.5-x86_64-bin-DVD1.iso
    链接:https://pan.baidu.com/s/1O9a-6Sn7riGWG3mVQssTGg  提取码:rud1
  2. jdk:jdk-8u144-linux-x64.tar.gz
    链接:https://pan.baidu.com/s/1TdaCDaT_qriDMjbYFyphPw  提取码:qulj
  3. hadoop:hadoop-2.7.2.tar.gz
    链接:https://pan.baidu.com/s/1Wt0mAUHKJDSYTUM5-u6CYw  提取码:oofe
  4. 或者官网:https://archive.apache.org/dist/hadoop/common/hadoop-2.7.2/

上述的如果百度云下载的慢的话,可以去各大开源论坛或者官网下载
博主使用的工具为Xshell,非常方便的一个软件,感兴趣的话可以动动自己的小手,去官网下载

本文是建立在 CentOS7已经安装,jdk也已安装好的情况下,jdk安装可以参考 jdk安装


一、前期环境配置

关闭防火墙

# 查看防火墙状态
[root@localhost dr]# firewall-cmd --state
running
# 关闭防火墙
[root@localhost dr]# systemctl stop firewalld.service
[root@localhost dr]# firewall-cmd --state
not running
# 禁止 firewall 开机启动
[root@localhost dr]# systemctl disable firewalld.service
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

修改配置hosts文件,并测试是否能ping通

# 查看本机地址 192.168.23.128

[root@localhost dr]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.23.128  netmask 255.255.255.0  broadcast 192.168.23.255
        inet6 fe80::5895:a1c7:da57:e4ad  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:a1:55:a1  txqueuelen 1000  (Ethernet)
        RX packets 213928  bytes 299951288 (286.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 22291  bytes 2345515 (2.2 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

# 修改配置hosts文件
[root@localhost dr]# vi /etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.23.128 master
~

# 测试是否设置成功
[root@localhost dr]# ping master
PING master (192.168.23.128) 56(84) bytes of data.
64 bytes from master (192.168.23.128): icmp_seq=1 ttl=64 time=0.020 ms
64 bytes from master (192.168.23.128): icmp_seq=2 ttl=64 time=0.113 ms
64 bytes from master (192.168.23.128): icmp_seq=3 ttl=64 time=0.023 ms
64 bytes from master (192.168.23.128): icmp_seq=4 ttl=64 time=0.122 ms

设置免密登录

[root@localhost dr]# ssh-keygen # 一直回车
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:8CSgRg7wOr5NWlwL1A17rW3CyA9X7RkpFbvP2MAHL4A root@master
The key's randomart image is:
+---[RSA 2048]----+
|+ . ..     o.    |
| = ...+ o o o    |
|  =. ooE.= *     |
| o. . +=+ = *    |
|o  . = =So B o   |
|... o = o   O    |
| . + . .   . +   |
|  *              |
| o .             |
+----[SHA256]-----+


# 给 master 配置免密
[root@localhost .ssh]# ssh-copy-id master
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed

/usr/bin/ssh-copy-id: WARNING: All keys were skipped because they already exist on the remote system.
                (if you think this is a mistake, you may want to use -f option)

 

二、安装Hadoop

1.解压Hadoop

  • 先把Hadoop的压缩文件放到 本地目录 /home/dr/Datafile/  这是我的目录,下文如是
     
  • 在  /usr/local/ 目录下创建 hadoop 文件夹
     
    [root@localhost /]# mkdir /usr/local/hadoop
    
    [root@localhost /]# cd /usr/local/
    
    [root@localhost local]# ll
    total 0
    drwxr-xr-x. 2 root root  6 Nov  5  2016 bin
    drwxr-xr-x. 2 root root  6 Nov  5  2016 etc
    drwxr-xr-x. 2 root root  6 Nov  5  2016 games
    drwxr-xr-x. 2 root root  6 Mar 29 01:32 hadoop
    drwxr-xr-x. 2 root root  6 Nov  5  2016 include
    drwxr-xr-x. 3 root root 26 Mar 28 04:43 java
    drwxr-xr-x. 2 root root  6 Nov  5  2016 lib
    drwxr-xr-x. 2 root root  6 Nov  5  2016 lib64
    drwxr-xr-x. 2 root root  6 Nov  5  2016 libexec
    drwxr-xr-x. 2 root root  6 Nov  5  2016 sbin
    drwxr-xr-x. 5 root root 49 Mar 28 01:26 share
    drwxr-xr-x. 2 root root  6 Nov  5  2016 src
    

     

  • 把hadoop压缩包解压到 /hadoop文件下
     
    [root@localhost local]# tar -zxvf /home/dr/Datafile/hadoop-2.7.7.tar.gz -C /usr/local/hadoop/
    hadoop-2.7.7/
    hadoop-2.7.7/bin/
    hadoop-2.7.7/bin/hadoop.cmd
    hadoop-2.7.7/bin/rcc
    hadoop-2.7.7/bin/test-container-executor
    hadoop-2.7.7/bin/mapred
    hadoop-2.7.7/bin/yarn
    hadoop-2.7.7/bin/yarn.cmd
    hadoop-2.7.7/bin/hadoop
    

    -C 才可以成功解压到指定目录

2.将Hadoop添加到环境变量

  • 获取Hadoop安装路径
     
    [root@localhost hadoop-2.7.7]# pwd
    /usr/local/hadoop/hadoop-2.7.7
    

     

  • 编辑 /etc/profile 文件,把环境配置加在最后
     
    export HADOOP_HOME=/usr/local/hadoop/hadoop-2.7.7
    export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin
    

     

  • 让修改后的文件生效,并测试Hadoop是否安装成功

     
    [root@localhost hadoop-2.7.7]# source /etc/profile
    
    [root@localhost hadoop-2.7.7]# hadoop version
    Hadoop 2.7.7
    Subversion Unknown -r c1aad84bd27cd79c3d1a7dd58202a8c3ee1ed3ac
    Compiled by stevel on 2018-07-18T22:47Z
    Compiled with protoc 2.5.0
    From source with checksum 792e15d20b12c74bd6f19a1fb886490
    This command was run using /usr/local/hadoop/hadoop-2.7.7/share/hadoop/common/hadoop-common-2.7.7.jar
    

     

3.Hadoop目录结构

[root@localhost hadoop-2.7.7]# ll
total 112
drwxr-xr-x. 2 dr ftp   194 Jul 18  2018 bin # 存放对Hadoop相关服务(HDFS,YARN)进行操作的脚本
drwxr-xr-x. 3 dr ftp    20 Jul 18  2018 etc # Hadoop的配置文件目录,存放Hadoop的配置文件
drwxr-xr-x. 2 dr ftp   106 Jul 18  2018 include 
drwxr-xr-x. 3 dr ftp    20 Jul 18  2018 lib # 存放Hadoop的本地库(对数据进行压缩解压缩功能)
drwxr-xr-x. 2 dr ftp   239 Jul 18  2018 libexec
-rw-r--r--. 1 dr ftp 86424 Jul 18  2018 LICENSE.txt
-rw-r--r--. 1 dr ftp 14978 Jul 18  2018 NOTICE.txt
-rw-r--r--. 1 dr ftp  1366 Jul 18  2018 README.txt
drwxr-xr-x. 2 dr ftp  4096 Jul 18  2018 sbin
drwxr-xr-x. 4 dr ftp    31 Jul 18  2018 share # 存放Hadoop的依赖jar包、文档、和官方案例

 

三、Hadoop伪分布式配置(重点)

1.说明配置文件的一些注意事项

在Hadoop安装目录/etc/下创建一个 hadoop 文件夹,如果没有特别说明,所以下面所有配置文件都要进这个 /usr/local/hadoop/hadoop-2.7.7/etc/hadoop

2.配置 hadoop-env.sh(在hadoop-2.7.7/etc/hadoop/ 下

[root@localhost hadoop]# vi hadoop-env.sh

为了方便查找我们要改的信息,在命令行模式,输入 :se nu 显示行号

然后找到25行,跟33行改成所对应的jdk目录,跟hadoop目录(注意这里是hadoo目录后面还有/ect/hadoop)

# 修改前
24 # The java implementation to use.
25 export JAVA_HOME=${JAVA_HOME}
26
27 # The jsvc implementation to use. Jsvc is required to run secure datanodes
28 # that bind to privileged ports to provide authentication of data transfer
29 # protocol.  Jsvc is not required if SASL is configured for authentication of
30 # data transfer protocol using non-privileged ports.
31 #export JSVC_HOME=${JSVC_HOME}
32
33 export HADOOP_CONF_DIR=${HADOOP_CONF_DIR:-"/etc/hadoop"}

#修改后
24 # The java implementation to use.
25 export JAVA_HOME=/usr/local/java/jdk1.8.0_171
26
27 # The jsvc implementation to use. Jsvc is required to run secure datanodes
28 # that bind to privileged ports to provide authentication of data transfer
29 # protocol.  Jsvc is not required if SASL is configured for authentication of
30 # data transfer protocol using non-privileged ports.
31 #export JSVC_HOME=${JSVC_HOME}
32
33 export HADOOP_CONF_DIR=/usr/local/hadoop/hadoop-2.7.7/etc/hadoop

 保存并退出 ESC :wq! ,使配置文件立即生效

3.配置四个文件 core-site.xml、hdfs-site.xml、mapred-site.xml、yarn-site.xml

首先在hadoop目录下: /usr/local/hadoop/hadoop-2.7.7 ,创建一个新的 tmp 文件夹

编辑  core-site.xml

[root@localhost hadoop]# vi core-site.xml

<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://master:9000</value>   # master 是你自己的主机名
</property>
<property>
  <name>hadoop.tmp.dir</name>
  <value>/usr/local/hadoop/hadoop-2.7.7/tmp</value>  # 改成你自己的文件地址
</property>
</configuration>

 编辑 hdfs-site.xml

vim  hdfs-site.xml

# 照抄

<configuration>
<property>
  <name>dfs.replication</name>
 <value>1</value>
</property>

<!--设置hdfs的操作权限,false表示任何用户都可以在hdfs上操作文件-->
<property>
  <name>dfs.permissions</name>
  <value>false</value>
 </property>
</configuration>

 编辑 mapred-site.xml

这个文件初始时是没有的,但是有一个模板文件,mapred-site.xml.template

所以需要拷贝一份,并重命名为mapred-site.xml使用命令:

cp ./mapred-site.xml.template ./mapred-site.xml

 然后编辑打开 mapred-site.xml

vim mapred-site.xml

# 直接复制

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

 编辑 yarn-site.xml

vim yarn-site.xml


# 直接复制, 修改 master

<configuration>
<property>
   <!--指定yarn的老大 resoucemanager的地址-->
   <name>yarn.resourcemanager.hostname</name>:
   <value>master</value>
</property>       
<property>
      <!--NodeManager获取数据的方式-->
     <name>yarn.nodemanager.aux-services</name>
     <value>mapreduce_shuffle</value>
</property>
</configuration>

 编辑slaves文件

vim slaves


# 修改 localhost 为 master

四、查看及启动

 用命令 jps 查看在线的工作节点

[root@localhost hadoop]# jps
50451 Jps

# 我们可以看到没有启动hadoop,是没有任何节点在线的

格式化namenode

 在第一次安装hadoop的时候,需要对namenode进行格式化,以后请不要随便在去用这个命令格式化namenode

[root@localhost hadoop]# hadoop namenode -format

# 如果成功会有 有 successfully 提示

21/03/29 02:43:46 INFO common.Storage: Storage directory /usr/local/hadoop/hadoop-2.7.7/tmp/dfs/name has been successfully formatted.
21/03/29 02:43:46 INFO namenode.FSImageFormatProtobuf: Saving image file /usr/local/hadoop/hadoop-2.7.7/tmp/dfs/name/current/fsimage.ckpt_0000000000000000000 using no compression
21/03/29 02:43:46 INFO namenode.FSImageFormatProtobuf: Image file /usr/local/hadoop/hadoop-2.7.7/tmp/dfs/name/current/fsimage.ckpt_0000000000000000000 of size 321 bytes saved in 0 seconds.
21/03/29 02:43:46 INFO namenode.NNStorageRetentionManager: Going to retain 1 images with txid >= 0
21/03/29 02:43:46 INFO util.ExitUtil: Exiting with status 0
21/03/29 02:43:46 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at master/192.168.23.128
************************************************************/

 启动hadoop

因为我们已经配置hadoop的环境变量了,所以不要在sbin 目录下启动,在任何目录下直接用这个命令都能启动hadoop

直接使用这个命令

start-dfs.sh


[root@localhost hadoop]# jps
50788 DataNode
51093 Jps
50649 NameNode
50970 SecondaryNameNode


# 出现上面这些说明hadoop伪分布式配置好了。

 打开浏览器输入 http://master:50070 查看能成功打开 namenode状态信息

五、实例测试

既然已经装好了hadoop了,那么我们来试试官方给出的wordcount实例操作一下,感受hadoop的强大吧。

1.创建一个本地文件1.txt:

目录我选择为:/home/dr/test.txt

输入命令:

vim test.txt

# 输入下面内容

i like hadoop
and i like study
i like java
i like jdk
i like java jdk hadoop

# 退出保存

2.上传到hdfs文件系统上

 我的test.txt是在/home/dr/下

首先先在hdfs的根目录下创建一个input目录,使用命令:

hdfs dfs -mkdir /input

然后上传到hdfs上:(确保你当前的路径在/home/dr下)

hdfs dfs -put ./test.txt  /input

 然后查看是否成功上传:

hdfs dfs -ls /input

 3.使用命令让hadoop工作

在上面的启动hadoop中,我们只启动hdfs,没有启动yarn,因此我们先使用命令启动yarn:

start-yarn.sh

 然后直接使用命令:

# 因hadoopb版本不一致,因此解压缩后 share 文件夹内的 jar 包名版本会有些不一致
hadoop jar ./hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.7.jar wordcount /input /output

我们看到hadoop已经跑起来了,最后的successful代表工作成功! 

4.查看输出结果

hadoop工作成功后会自己在指定路径/output 生成两个文件
我们看一下

 hdfs dfs -ls /output

第一个文件/output/_SUCCESS:是表示工作成功的文件,没有具体的文本,这个我们忽略

第二个文件/output/part-r-00000:才是我们真正的输出文件

查看一下结果:

hdfs dfs -cat /output/part-r-00000

最后得出了每个单词出现的次数 


本文借鉴了 Centos Linux上安装hadoop伪分布式详细过程