ssh user@host
使用ssh远程登录Centos7会提示：
The authenticity of host 'host (192.168.1.1)' can't be established. RSA key fingerprint is 98:2e:d7:e0:de:9f:ac:67:28:c2:42:2d:37:16:58:4d. Are you sure you want to continue connecting (yes/no)?
意思是无法确认host主机的真实性，只知道他的公钥，需要继续吗？
填写yes后输入密码远程登录进去到Centos，用户的公钥会保存在/root/.ssh/known_hosts中.