SSH免密码登录设置

　　两台Linux主机需要从其中一台ssh至另外一台需要手动输入密码，通过以下设置免密码登录

　　在需要远程登录的源主机生成秘钥，例如需要在Jenkins远程登录其他主机用于构建发送文件则在Jenkins主机上面执行

ssh-keygen -t rsa

　　会在文件夹/root/.ssh下面生产公钥和私钥

　　把秘钥复制至需要免密登录的目的远程主机，第一次拷贝需要输入一次密码

ssh-copy-id -i ~/.ssh/id_rsa.pub root@10.1.3.4

　　会在远程主机的文件夹/root/.ssh下面自动生成文件authorized_keys 文件内容为公钥id_ras.pub一样

　　也可以直接把公钥复制编辑需要远程登录的主机的/root/.ssh/authorized_keys文件

　　验证能否免密登录

ssh 10.1.3.4

　　拍错

　　在需要登录的远程主机跟换以后但是ip保存原来的进行秘钥拷贝时候会出现以下错误提示

/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed

/usr/bin/ssh-copy-id: ERROR: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
ERROR: @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
ERROR: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
ERROR: IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
ERROR: Someone could be eavesdropping on you right now (man-in-the-middle attack)!
ERROR: It is also possible that a host key has just been changed.
ERROR: The fingerprint for the ECDSA key sent by the remote host is
ERROR: SHA256:pTp06EZ6R6ntAYVjQSD3I2/Zy8BPxWj3NVL10SmrSWI.
ERROR: Please contact your system administrator.
ERROR: Add correct host key in /root/.ssh/known_hosts to get rid of this message.
ERROR: Offending ECDSA key in /root/.ssh/known_hosts:35
ERROR: ECDSA host key for 192.168.1.99 has changed and you have requested strict checking.
ERROR: Host key verification failed.

 　　解决办法

　　删除/root/.ssh/known_hosts对应主机哪行重新拷贝秘钥

　　如果远程主机无法直接root登录可以使用以下命令拷贝秘钥

ssh-copy-id -i ~/.ssh/id_rsa.pub username@$ip

 　　用户名+@+IP地址