WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED

 ssh node2
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@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
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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 the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
f3:5f:6b:f6:0f:6b:e1:55:79:78:9a:07:34:59:26:8b.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending key in /root/.ssh/known_hosts:3
RSA host key for node2 has changed and you have requested strict checking.
Host key verification failed.
[root@node1 ~]#

解决办法：
先cat一下家目录的.ssh/know_hosts
cat ~/.ssh/known_hosts

[root@node1 ~]# cat .ssh/known_hosts
node3,192.168.2.163 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAurtPR34TxJ8XGLjsSgHorIc25oa8btjMa4nJ2oO83HfFesXhKxk1MUKW1QE1VIsuSct1BGSnKGEHdJ+YfogGsZ7+EOOT/Ems9rtIQuAKinHOISdGX0T18dpnSkCdqPifVvo5rswRWFByiKMgDSg6pIDWnpSubABHvkPL1VNk2zLjIBHhjN43xnNAxY8m6Swx5wDAUP6O1UL5ZGr3a4jyzoYHjyMWQ8XVh8OlUpnSYeHNUjM15TKwZBLr9txffYAwFEjcNBNPP5ubno4SRCMULI2MvKM83sRq1tvju2mKRcd7IRkZZZvEMnYgnxNOz3/Tref6rm62KtwKEoB5j0q/tQ==
node1,192.168.2.161 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA1t5cVbnEO1WLflupG8vfsVpKo3iCWG7AM4wBqp7YpWFQ0weE2sHw7Vfv5JbSEsZlueLsxG24yk61UujztUqDGXXP6qC1Wy17I9Eu+AqNH5DeVY8lZZ1HHo1q0YJFEGU9ZVZLLAbpfebF5DYtW5XTZWFgTuKhG1Dwp6NCc7ECJLLmi4+cFy6sgvBlA/xYsdNtQ8z8ldp/4CTe3VeW08h6/ad0XqU24DAHdMf6Koqsc6/jwOKImxQ89x112xMuSoWLWduzraYWt5PrwwYKFKkty4cuG2NZPYqSuauuxHLPSQlUUj/bclgA8DlbQucA57BYwVhWe8Ta4IZwJrDQoULIDQ==
node2,192.168.2.162 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAurtPR34TxJ8XGLjsSgHorIc25oa8btjMa4nJ2oO83HfFesXhKxk1MUKW1QE1VIsuSct1BGSnKGEHdJ+YfogGsZ7+EOOT/Ems9rtIQuAKinHOISdGX0T18dpnSkCdqPifVvo5rswRWFByiKMgDSg6pIDWnpSubABHvkPL1VNk2zLjIBHhjN43xnNAxY8m6Swx5wDAUP6O1UL5ZGr3a4jyzoYHjyMWQ8XVh8OlUpnSYeHNUjM15TKwZBLr9txffYAwFEjcNBNPP5ubno4SRCMULI2MvKM83sRq1tvju2mKRcd7IRkZZZvEMnYgnxNOz3/Tref6rm62KtwKEoB5j0q/tQ==
node4,192.168.2.164 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAurtPR34TxJ8XGLjsSgHorIc25oa8btjMa4nJ2oO83HfFesXhKxk1MUKW1QE1VIsuSct1BGSnKGEHdJ+YfogGsZ7+EOOT/Ems9rtIQuAKinHOISdGX0T18dpnSkCdqPifVvo5rswRWFByiKMgDSg6pIDWnpSubABHvkPL1VNk2zLjIBHhjN43xnNAxY8m6Swx5wDAUP6O1UL5ZGr3a4jyzoYHjyMWQ8XVh8OlUpnSYeHNUjM15TKwZBLr9txffYAwFEjcNBNPP5ubno4SRCMULI2MvKM83sRq1tvju2mKRcd7IRkZZZvEMnYgnxNOz3/Tref6rm62KtwKEoB5j0q/tQ==

进入此文件
vim ~/.ssh/known_hosts

删除node2的相关rsa的信息即可.