[root@zk01 ~]# ssh localhost
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:r86jc/Vu8phhiKKDSntetfkmksjQ606ZlUP8XNYe44U.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /root/.ssh/known_hosts:10
Password authentication is disabled to avoid man-in-the-middle attacks.
Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks.
Permission denied (publickey,password,keyboard-interactive).
说明： Add correct host key in /root/.ssh/known_hosts to get rid of this message. 重点在这句话
分析： ssh登录过某机器后，因某机器有变动（更换ip等），再次登录不了，报错！！！
解决过程：
[root@zk01 ~]# mv /root/.ssh/known_hosts /root/.ssh/known_hosts.bak
[root@zk01 ~]# ssh -o StrictHostKeyChecking=no 172.16.38.130
Warning: Permanently added '172.16.38.130' (ECDSA) to the list of known hosts.
root@172.16.38.130's password:
Last login: Sun Oct 1 12:02:21 2017 from 172.16.74.104
[root@zk01 ~]# ssh localhost ## 输入密码，OK！
Warning: Permanently added 'localhost' (ECDSA) to the list of known hosts.
root@localhost's password:
Last login: Sun Oct 1 12:04:59 2017 from zk01