案例1：安装Hadoop
案例2：安装配置Hadoop
1 案例1：安装Hadoop
1.1 问题
本案例要求安装单机模式Hadoop：
单机模式安装Hadoop
安装JAVA环境
设置环境变量，启动运行
1.2 步骤
实现此案例需要按照如下步骤进行。
步骤一：环境准备
1）配置主机名为nn01，ip为192.168.1.21，配置yum源（系统源）
备注：由于在之前的案例中这些都已经做过，这里不再重复，不会的学员可以参考之前的案例
2）安装java环境
[root@nn01 ~]# yum -y install java-1.8.0-openjdk-devel
[root@nn01 ~]# java -version
openjdk version "1.8.0_131"
OpenJDK Runtime Environment (build 1.8.0_131-b12)
OpenJDK 64-Bit Server VM (build 25.131-b12, mixed mode)
[root@nn01 ~]# jps
1235 Jps
3）安装hadoop
[root@nn01 ~]# tar -xf hadoop-2.7.6.tar.gz
[root@nn01 ~]# mv hadoop-2.7.6 /usr/local/hadoop
[root@nn01 ~]# cd /usr/local/hadoop/
[root@nn01 hadoop]# ls
bin include libexec NOTICE.txt sbin
etc lib LICENSE.txt README.txt share
[root@nn01 hadoop]# ./bin/hadoop //报错，JAVA_HOME没有找到
Error: JAVA_HOME is not set and could not be found.
[root@nn01 hadoop]#
4）解决报错问题
[root@nn01 hadoop]# rpm -ql java-1.8.0-openjdk
[root@nn01 hadoop]# cd ./etc/hadoop/
[root@nn01 hadoop]# vim hadoop-env.sh
25 export \
JAVA_HOME="/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.131-11.b12.el7.x86_64/jre"
33 export HADOOP_CONF_DIR="/usr/local/hadoop/etc/hadoop"
[root@nn01 ~]# cd /usr/local/hadoop/
[root@nn01 hadoop]# ./bin/hadoop
Usage: hadoop [--config confdir] [COMMAND | CLASSNAME]
CLASSNAME run the class named CLASSNAME
or
where COMMAND is one of:
fs run a generic filesystem user client
version print the version
jar <jar> run a jar file
note: please use "yarn jar" to launch
YARN applications, not this command.
checknative [-a|-h] check native hadoop and compression libraries availability
distcp <srcurl> <desturl> copy file or directories recursively
archive -archiveName NAME -p <parent path> <src>* <dest> create a hadoop archive
classpath prints the class path needed to get the
credential interact with credential providers
Hadoop jar and the required libraries
daemonlog get/set the log level for each daemon
trace view and modify Hadoop tracing settings
Most commands print help when invoked w/o parameters.
[root@nn01 hadoop]# mkdir /usr/local/hadoop/aa
[root@nn01 hadoop]# ls
bin etc include lib libexec LICENSE.txt NOTICE.txt aa README.txt sbin share
[root@nn01 hadoop]# cp *.txt /usr/local/hadoop/aa
[root@nn01 hadoop]# ./bin/hadoop jar \
share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.6.jar wordcount aa bb //wordcount为参数 统计aa这个文件夹，存到bb这个文件里面（这个文件不能存在，要是存在会报错，是为了防止数据覆盖）
[root@nn01 hadoop]# cat bb/part-r-00000 //查看
2 案例2：安装配置Hadoop
2.1 问题
本案例要求：
另备三台虚拟机，安装Hadoop
使所有节点能够ping通，配置SSH信任关系
节点验证
2.2 方案
准备四台虚拟机，由于之前已经准备过一台，所以只需再准备三台新的虚拟机即可，安装hadoop，使所有节点可以ping通，配置SSH信任关系，如图-1所示：
图-1
2.3 步骤
实现此案例需要按照如下步骤进行。
步骤一：环境准备
1）三台机器配置主机名为node1、node2、node3，配置ip地址（ip如图-1所示），yum源（系统源）
2）编辑/etc/hosts（四台主机同样操作，以nn01为例）
[root@nn01 ~]# vim /etc/hosts
192.168.1.21 nn01
192.168.1.22 node1
192.168.1.23 node2
192.168.1.24 node3
3）安装java环境，在node1，node2，node3上面操作（以node1为例）
[root@node1 ~]# yum -y install java-1.8.0-openjdk-devel
4）布置SSH信任关系
[root@nn01 ~]# vim /etc/ssh/ssh_config //第一次登陆不需要输入yes
Host *
GSSAPIAuthentication yes
StrictHostKeyChecking no
[root@nn01 .ssh]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
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:Ucl8OCezw92aArY5+zPtOrJ9ol1ojRE3EAZ1mgndYQM root@nn01
The key's randomart image is:
+---[RSA 2048]----+
| o*E*=. |
| +XB+. |
| ..=Oo. |
| o.+o... |
| .S+.. o |
| + .=o |
| o+oo |
| o+=.o |
| o==O. |
+----[SHA256]-----+
[root@nn01 .ssh]# for i in 21 22 23 24 ; do ssh-copy-id 192.168.1.$i; done
//部署公钥给nn01，node1，node2，node3
5）测试信任关系
[root@nn01 .ssh]# ssh node1
Last login: Fri Sep 7 16:52:00 2018 from 192.168.1.21
[root@node1 ~]# exit
logout
Connection to node1 closed.
[root@nn01 .ssh]# ssh node2
Last login: Fri Sep 7 16:52:05 2018 from 192.168.1.21
[root@node2 ~]# exit
logout
Connection to node2 closed.
[root@nn01 .ssh]# ssh node3
步骤二：配置hadoop
1）修改slaves文件
[root@nn01 ~]# cd /usr/local/hadoop/etc/hadoop
[root@nn01 hadoop]# vim slaves
node1
node2
node3
2）hadoop的核心配置文件core-site
[root@nn01 hadoop]# vim core-site.xml
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://nn01:9000</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/var/hadoop</value>
</property>
</configuration>
[root@nn01 hadoop]# mkdir /var/hadoop //hadoop的数据根目录
[root@nn01 hadoop]# ssh node1 mkdir /var/hadoop
[root@nn01 hadoop]# ssh node2 mkdir /var/hadoop
[root@nn01 hadoop]# ssh node3 mkdir /var/hadoop
3）配置hdfs-site文件
[root@nn01 hadoop]# vim hdfs-site.xml
<configuration>
<property>
<name>dfs.namenode.http-address</name>
<value>nn01:50070</value>
</property>
<property>
<name>dfs.namenode.secondary.http-address</name>
<value>nn01:50090</value>
</property>
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
</configuration>
4）同步配置到node1，node2，node3
[root@nn01 hadoop]# yum –y install rsync //同步的主机都要安装rsync
[root@nn01 hadoop]# for i in 22 23 24 ; do rsync -aSH --delete /usr/local/hadoop/
\ 192.168.1.$i:/usr/local/hadoop/ -e 'ssh' & done
[1] 23260
[2] 23261
[3] 23262
5）查看是否同步成功
[root@nn01 hadoop]# ssh node1 ls /usr/local/hadoop/
bin
etc
include
lib
libexec
LICENSE.txt
NOTICE.txt
bb
README.txt
sbin
share
aa
[root@nn01 hadoop]# ssh node2 ls /usr/local/hadoop/
bin
etc
include
lib
libexec
LICENSE.txt
NOTICE.txt
bb
README.txt
sbin
share
aa
[root@nn01 hadoop]# ssh node3 ls /usr/local/hadoop/
bin
etc
include
lib
libexec
LICENSE.txt
NOTICE.txt
bb
README.txt
sbin
share
aa
步骤三：格式化
[root@nn01 hadoop]# cd /usr/local/hadoop/
[root@nn01 hadoop]# ./bin/hdfs namenode -format //格式化 namenode
[root@nn01 hadoop]# ./sbin/start-dfs.sh //启动
[root@nn01 hadoop]# jps //验证角色
23408 NameNode
23700 Jps
23591 SecondaryNameNode
[root@nn01 hadoop]# ./bin/hdfs dfsadmin -report //查看集群是否组建成功
Live datanodes (3): //有三个角色成功
转载：https://blog.csdn.net/xie_qi_chao/article/details/104725454
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