三台7.3的虚拟机：
server1
server2
server3
单机模式（standalone）：单机模式是Hadoop的默认模式。这种模式在一台单机上运行，没有分布式文件系统，而是直接读写本地操作系统的文件系统。
1.建立hadoop用户：
[root@server1 ~]# useradd hadoop [root@server1 ~]# id hadoop uid=1000(hadoop) gid=1000(hadoop) groups=1000(hadoop) [root@server1 ~]# passwd hadoop Changing password for user hadoop. New password: BAD PASSWORD: The password is shorter than 8 characters Retype new password: passwd: all authentication tokens updated successfully. [root@server1 ~]#2.安装hadoop和jdk
[root@server1 ~]# mv * /home/hadoop/ [root@server1 ~]# su - hadoop [hadoop@server1 ~]$ tar zxf hadoop-3.0.3.tar.gz [hadoop@server1 ~]$ tar zxf jdk-8u181-linux-x64.tar.gz [hadoop@server1 ~]$ ln -s hadoop-3.0.3 hadoop [hadoop@server1 ~]$ ln -s jdk1.8.0_181/ java [hadoop@server1 ~]$ cd hadoop [hadoop@server1 hadoop]$ ls [hadoop@server1 hadoop]$ cd etc/ [hadoop@server1 etc]$ ls hadoop [hadoop@server1 etc]$ cd hadoop/ [hadoop@server1 hadoop]$ ls [hadoop@server1 hadoop]$ vim hadoop-env.sh 54 export JAVA_HOME=/home/hadoop/java配置环境变量：
[hadoop@server1 hadoop]$ cd [hadoop@server1 ~]$ cd java/ [hadoop@server1 java]$ vim ~/.bash_profile #配置环境变量 PATH=$PATH:$HOME/.local/bin:$HOME/bin:$HOME/java/bin [hadoop@server1 java]$ source ~/.bash_profile [hadoop@server1 java]$ jps #查看java进程 10452 Jps3.测试：
[hadoop@server1 ~]$ cd hadoop [hadoop@server1 hadoop]$ pwd /home/hadoop/hadoop [hadoop@server1 hadoop]$ mkdir input [hadoop@server1 hadoop]$ cp etc/hadoop/*.xml input/ [hadoop@server1 hadoop]$ ls input/ capacity-scheduler.xml hdfs-site.xml kms-site.xml core-site.xml httpfs-site.xml mapred-site.xml hadoop-policy.xml kms-acls.xml yarn-site.xml [hadoop@server1 hadoop]$ [hadoop@server1 hadoop]$ bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-3.0.3.jar grep input output 'dfs[a-z.]+' [hadoop@server1 hadoop]$ cd output/ [hadoop@server1 output]$ ls part-r-00000 _SUCCESS [hadoop@server1 output]$ cat part-r-00000 1 dfsadmin这种模式也是在一台单机上运行，但用不同的Java进程模仿分布式运行中的各类结点。
没有所谓的在多台机器上进行真正的分布式计算，故称为"伪分布式"。
伪分布模式在“单节点集群”上运行Hadoop，其中所有的守护进程都运行在同一台机器上。该模式在单机模式之上增加了代码调试功能，允许你检查内存使用情况，HDFS输入输出，以及其他的守护进程交互。
1.编辑配置文件
[hadoop@server1 ~]$ cd hadoop [hadoop@server1 hadoop]$ cd etc/hadoop/ [hadoop@server1 hadoop]$ vim core-site.xml 19 <configuration> 20 <property> 21 <name>fs.defaultFS</name> 22 <value>hdfs://172.25.60.1:9000</value> 23 </property> 24 </configuratioN> [hadoop@server1 hadoop]$ vim hdfs-site.xml 20 <property> 21 <name>dfs.replication</name> 22 <value>1</value> ##自己充当节点 23 </property>2.为了方便，设置免密
[hadoop@server1 hadoop]$ cd [hadoop@server1 ~]$ ssh-keygen [hadoop@server1 ~]$ ssh-copy-id 172.25.60.1 [hadoop@server1 ~]$ ssh-copy-id localhost [hadoop@server1 ~]$ ssh-copy-id server13.格式化，并开启服务
[hadoop@server1 ~]$ cd hadoop [hadoop@server1 hadoop]$ bin/hdfs namenode -format [hadoop@server1 hadoop]$ cd sbin/ [hadoop@server1 sbin]$ ./start-dfs.sh Starting namenodes on [server1] Starting datanodes Starting secondary namenodes [server1] [hadoop@server1 sbin]$ jps 4417 DataNode 4314 NameNode 4602 SecondaryNameNode 4746 Jps4.打开浏览器：http://172.25.60.1:9000
http://172.25.60.1:9870
5.测试：创建目录，并上传
[hadoop@server1 hadoop]$ pwd /home/hadoop/hadoop [hadoop@server1 hadoop]$ bin/hdfs dfs -mkdir -p /user/hadoop [hadoop@server1 hadoop]$ bin/hdfs dfs -ls [hadoop@server1 hadoop]$ bin/hdfs dfs -put input/ [hadoop@server1 hadoop]$ bin/hdfs dfs -ls Found 1 items drwxr-xr-x - hadoop supergroup 0 2019-05-23 02:41 input刷新浏览器：
点击：Browse the system
点击：user-->hadoop-->input
6.删除input和output文件，重新执行命令
[hadoop@server1 hadoop]$ rm -fr input/ output/ [hadoop@server1 hadoop]$ ls bin include libexec logs README.txt share etc lib LICENSE.txt NOTICE.txt sbin [hadoop@server1 hadoop]$ bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-3.0.3.jar wordcount input output #计算文件里的每个单词出现的次数此时input和output不会出现在当前目录下，而是上传到了分布式文件系统中，网页上可以看到
刷新浏览器：
点击output-->_SUCCESS(如果要查看结果，就可以点击下载)
命令查看：
[hadoop@server1 hadoop]$ bin/hdfs dfs -cat output/* [hadoop@server1 hadoop]$ bin/hdfs dfs -get output #从分布式系统中get下来output目录 [hadoop@server1 hadoop]$ cd output/ [hadoop@server1 output]$ ls part-r-00000 _SUCCESS [hadoop@server1 output]$ cat part-r-00000真正的分布式，由3个及以上的实体机或者虚拟机组件的集群。Hadoop守护进程运行在一个集群上。
1.清除原来的数据
[hadoop@server1 hadoop]$ sbin/stop-dfs.sh Stopping namenodes on [server1] Stopping datanodes Stopping secondary namenodes [server1] [hadoop@server1 hadoop]$ cd /tmp/ [hadoop@server1 tmp]$ ls hadoop hadoop-hadoop hsperfdata_hadoop [hadoop@server1 tmp]$ rm -fr * [hadoop@server1 tmp]$ logout2.新开两个虚拟机，当做新节点
[root@server2 ~]# useradd -u 1000 hadoop [root@server3 ~]# useradd -u 1000 hadoop3.安装nfs
[root@server1 ~]# yum install -y nfs-utils [root@server2 ~]# yum install -y nfs-utils [root@server3 ~]# yum install -y nfs-utils [root@server1 ~]# systemctl start rpcbind [root@server1 ~]# systemctl is-enabled rpcbind indirect [root@server2 ~]# systemctl start rpcbind [root@server3 ~]# systemctl start rpcbind4.在server1上开启服务，配置
[root@server1 ~]# systemctl start nfs-server [root@server1 ~]# vim /etc/exports /home/hadoop *(rw,anonuid=1000,anongid=1000) [root@server1 ~]# exportfs -rv exporting *:/home/hadoop [root@server1 ~]# exportfs -v /home/hadoop <world>(rw,wdelay,root_squash,no_subtree_check,anonuid=1000,anongid=1000,sec=sys,rw,secure,root_squash,no_all_squash)5.server2/server3：挂载nfs
[root@server2 ~]# showmount -e server1 Export list for server1: /home/hadoop * [root@server2 ~]# mount 172.25.60.1:/home/hadoop/ /home/hadoop/ [root@server2 ~]# df 172.25.60.1:/home/hadoop 17811456 2817792 14993664 16% /home/hadoop [root@server3 ~]# showmount -e server1 Export list for server1: /home/hadoop * [root@server3 ~]# mount 172.25.60.1:/home/hadoop/ /home/hadoop/ [root@server3 ~]# df6.此时发现可以免密登录（因为是挂载上的）
[hadoop@server1 ~]$ ssh 172.25.60.2 Last login: Thu May 23 06:00:34 2019 from server1 [hadoop@server2 ~]$ ssh 172.25.60.3 Last login: Thu May 23 06:07:42 2019 from server17.重新编辑文件
[hadoop@server1 ~]$ cd hadoop [hadoop@server1 hadoop]$ ls bin include libexec logs output sbin etc lib LICENSE.txt NOTICE.txt README.txt share [hadoop@server1 hadoop]$ cd etc/hadoop/ [hadoop@server1 hadoop]$ vim workers 172.25.60.2 172.25.60.3修改节点数：
[hadoop@server3 hadoop]$ vim hdfs-site.xml <value>2</value>在一个地方编辑，其他节点都有了:
8.格式化，并启动服务
[hadoop@server1 hadoop]$ bin/hdfs namenode -format [hadoop@server1 hadoop]$ sbin/start-dfs.sh Starting namenodes on [server1] Starting datanodes Starting secondary namenodes [server1]从节点可以看到datanode信息:
[hadoop@server2 ~]$ jps 10834 Jps 10772 DataNode [hadoop@server3 ~]$ jps 10842 Jps 10780 DataNode9.测试:刷新浏览器，点击Datanodes，有两个节点
[hadoop@server1 hadoop]$ bin/hdfs dfs -mkdir -p /user/hadoop [hadoop@server1 hadoop]$ bin/hdfs dfs -mkdir input [hadoop@server1 hadoop]$ bin/hdfs dfs -put etc/hadoop/*.xml input [hadoop@server1 hadoop]$ bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-3.0.3.jar grep input output 'dfs[a-z.]+'
