1、Warning: the ECDSA host key for 'slave2' differs from the key for the IP address '219.244.48.234'
Offending key for IP in /home/hadoop/.ssh/known_hosts:3
Matching host key in /home/hadoop/.ssh/known_hosts:8
問題解決：將Offending key for IP in /home/hadoop/.ssh/known_hosts:3中提示的known_hosts文件打開，（用：set nu 添加里面的編號）刪除第三行內容就ok了，問題完美解決
但是還有提示：Warning: Permanently added the ECDSA host key for IP address '219.244.48.234' to the list of known hosts.
問題解決：在問題主機輸入：ssh-keygen -R 219.244.48.234（注意是在出錯IP主機操作）
完美問題解決
如果ssh slave1 沒有反應就是ssh沒有裝好或是無密碼登錄沒有配好
如果能ssh自己本機，不能ssh Master機器，很可能是hosts/hostname文件裏面添加的Slave和Master的問題，很可能是IP輸入錯誤