用ssh登录一个机器（换过ip地址）会出现如下错误
weiguohui@weiguohui1-virtual-machine:~/.ssh$ ssh 172.16.33.53
The authenticity of host ‘172.16.33.53 (172.16.33.53)‘ can‘t be established.
ECDSA key fingerprint is 28:17:f7:c3:58:54:fb:6e:dd:b9:61:61:c4:8a:45:0f.
Are you sure you want to continue connecting (yes/no)?
Host key verification failed.
导致我的secondenamenode 和datanode 无法启动，最后通过查资料解决，是解决的方法为：
weiguohui@weiguohui1-virtual-machine:~/.ssh$ ssh -o StrictHostKeyChecking=no 172.16.33.53
然后再ssh 登录就不会报错了
The authenticity of host '172.16.33.53 (172.16.33.53)' can't be established的问题(日志六)
原文：http://www.cnblogs.com/beigongfengchen/p/5464669.html