1.登录B主机，先在B主机执行

ssh-keygen

2.设置id_rsa的权限

chmod 600 id_rsa

3.将生成的id_rsa.pub导入到authorized_keys

ssh-copy-id -i ./id_rsa.pub root@127.0.0.1

4.将id_rsa复制到A主机

 scp id_rsa_123 root@1.1.1.A:/home/

5.登录到A主机使用私钥登录

因为我设置了私钥密码   所以会

ssh -i /home/id_rsa_123 root@1.1.1.B