使用Linux配置Hadoop时，使用ssh登录到其它节点：
ssh data1
提示：
sh: Could not resolve hostname data1: Name or service not known
测试发现ping IP是通的，但是ping机器名却不行。解决这个问题的办法：
使用root登录，编辑hosts文件：
vi /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.2.200 master
192.168.2.201 data1
192.168.2.202 data2
192.168.2.203 data3
保存后，再使用ssh即可登录：
ssh data1
The authenticity of host 'data1 (192.168.2.201)' can't be established.
ECDSA key fingerprint is SHA256:QtXnEr32gZTHN0vODRjFsd1MnXsD8AjHv/PslgOT6KE.
ECDSA key fingerprint is MD5:dc:be:1c:c8:40:97:60:2f:05:d3:f3:e9:07:a3:d9:d6.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'data1,192.168.2.201' (ECDSA) to the list of known hosts.
Last login: Tue Jan 21 21:20:46 2020