在真机上再开启一台快照server4并且连接 在server4上建立hadoop用户并且安装nfs服务
[root@server4 ~]# useradd hadoop [root@server4 ~]# id hadoop [root@server4 ~]# yum install -y nfs-utils [root@server4 ~]# systemctl start rpcbind [root@server4 ~]# mount 172.25.5.1:/home/hadoop/ /home/hadoop/ [root@server4 ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/rhel-root 17811456 1138544 16672912 7% / devtmpfs 495476 0 495476 0% /dev tmpfs 507712 0 507712 0% /dev/shm tmpfs 507712 6856 500856 2% /run tmpfs 507712 0 507712 0% /sys/fs/cgroup /dev/sda1 1038336 132704 905632 13% /boot tmpfs 101544 0 101544 0% /run/user/0 172.25.5.1:/home/hadoop 17811456 2974720 14836736 17% /home/hadoop [root@server4 ~]# su - hadoop [hadoop@server4 ~]$ cd hadoop [hadoop@server4 hadoop]$ bin/hdfs --daemon start datanode [hadoop@server4 hadoop]$ jps在浏览器里面查看发现三个节点全部在线 在server4上传文件测试加入集群的状态是否健康
[hadoop@server4 hadoop]$ dd if=/dev/zero of=bigfile bs=1M count=500 [hadoop@server4 hadoop]$ bin/hdfs dfs -put bigfile在浏览其中查看 说明server4已经成功加入集群当中，并且状态健康
