目录
一、前提
二、具体操作
1、四台机器均需要做的操作，以server1为示例
2、在server1上做，将生成的密钥放在authorized_keys文件中
3、分别登录server2、server3、server4做如下操作，以server2为例。将id_rsa.pub复制到server1上
4、在server1上操作，将server2、server3、server4上的id_rsa.pub内容复制到authorized_keys文件中
5、将server1上authorized_keys的文件复制到server2、server3、server4上
6、在四台机器上都操作，进行文件夹授权
7、验证
一、前提
1、本集群近四台机器，设置其机器名称为server1、server2、server3、server4。
2、四台机器均需要创建用户alanchan，并且加入root用户组
二、具体操作
1、四台机器均需要做的操作，以server1为示例
[alanchan@server1 ~]$ssh-keygen -t rsa2、在server1上做，将生成的密钥放在authorized_keys文件中
[alanchan@server1 .ssh]$ touch ~/.ssh/authorized_keys
[alanchan@server1 .ssh]$ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
[alanchan@server1 .ssh]$ cd ~/.ssh/
[alanchan@server1 .ssh]$ cat authorized_keys
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAtM+WPAtjLuqsaDL3hVcSfwhUCNFCUenLgWlkRvUgJkGOn8Cfg+Ael6zHaL3EhqJU873pmNnn1yR4FQXYQxJ3omsisyugYvbufhmXjrQXrmtL2BJKWmylzgqpvpVBmJ4xjCbpTQvSWPi5oCIEY2crIMVocyGco/NA18qezN08h4hKQd/EScZGBpMmst5os0C1YUoqnWP83rcWxo1f/qXXBGCBCuXLDbLI94XxT6FMhfUXCwgRQxDXTMzqJ7rZRa5W/6lVueTEXivLbXUkis/Xo0CEAVSWt0hlNq4i9A2i2nISZLbB9Fp0GkwQhVZMNuKj8ccDzeNwPh8YxZSOFpCUKw== alanchan@server13、分别登录server2、server3、server4做如下操作，以server2为例。将id_rsa.pub复制到server1上
[alanchan@server2 .ssh]$ scp ~/.ssh/id_rsa.pub alanchan@server1:~/.ssh/server2.id_rsa.pub
alanchan@server1's password:
id_rsa.pub
#登录server1查看发送的结果
[alanchan@server1 .ssh]$ ll
总用量 28
-rw-r--r-- 1 alanchan root 398 9月 8 14:03 authorized_keys
-rw------- 1 alanchan root 1671 9月 8 13:40 id_rsa
-rw-r--r-- 1 alanchan root 398 9月 8 13:40 id_rsa.pub
-rw-r--r-- 1 alanchan root 2805 9月 7 09:07 known_hosts
-rw-r--r-- 1 alanchan root 398 9月 8 14:03 server2.id_rsa.pub
-rw-r--r-- 1 alanchan root 398 9月 8 14:04 server3.id_rsa.pub
-rw-r--r-- 1 alanchan root 398 9月 8 14:05 server4.id_rsa.pub4、在server1上操作，将server2、server3、server4上的id_rsa.pub内容复制到authorized_keys文件中
[alanchan@server1 .ssh]$ cat ~/.ssh/server2.id_rsa.pub >> ~/.ssh/authorized_keys
[alanchan@server1 .ssh]$ cat ~/.ssh/server3.id_rsa.pub >> ~/.ssh/authorized_keys
[alanchan@server1 .ssh]$ cat ~/.ssh/server4.id_rsa.pub >> ~/.ssh/authorized_keys
[alanchan@server1 .ssh]$ ll
总用量 28
-rw-r--r-- 1 alanchan root 1592 9月 8 14:06 authorized_keys
-rw------- 1 alanchan root 1671 9月 8 13:40 id_rsa
-rw-r--r-- 1 alanchan root 398 9月 8 13:40 id_rsa.pub
-rw-r--r-- 1 alanchan root 2805 9月 7 09:07 known_hosts
-rw-r--r-- 1 alanchan root 398 9月 8 14:03 server2.id_rsa.pub
-rw-r--r-- 1 alanchan root 398 9月 8 14:04 server3.id_rsa.pub
-rw-r--r-- 1 alanchan root 398 9月 8 14:05 server4.id_rsa.pub
[alanchan@server1 .ssh]$ cat authorized_keys
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAtM+WPAtjLuqsaDL3hVcSfwhUCNFCUenLgWlkRvUgJkGOn8Cfg+Ael6zHaL3EhqJU873pmNnn1yR4FQXYQxJ3omsisyugYvbufhmXjrQXrmtL2BJKWmylzgqpvpVBmJ4xjCbpTQvSWPi5oCIEY2crIMVocyGco/NA18qezN08h4hKQd/EScZGBpMmst5os0C1YUoqnWP83rcWxo1f/qXXBGCBCuXLDbLI94XxT6FMhfUXCwgRQxDXTMzqJ7rZRa5W/6lVueTEXivLbXUkis/Xo0CEAVSWt0hlNq4i9A2i2nISZLbB9Fp0GkwQhVZMNuKj8ccDzeNwPh8YxZSOFpCUKw== alanchan@server1
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAsOC9NDSK+uKB/D+J6rnpU6BUWyiZftGicYuvGkkNR32xGec5/qe3+dRfSVu1p8NWqlyECWZ15yTmYgwdmd8a72DYpGja4xFHPFBJ41RoCY6Lp35lF/V142MhcnLcpKaNN/h2VbCHEN/zYIVntoQgnLvtw3oIJwIwY4hkD2rmCPsJJfrA+m/c+alnGzWcBVmgy0ALEpx3p6lVqUZmpax6pzobd75RLumf6/5hzKDLeL/LnWbs7N7B74KVqVgHWeSlXSkfe1W4wc9PgpLCoowM9YWmr6B1aeSpdakUnh87/eZ7Owx6dwPGPhI3Y/PrITE9xdcpyq1ZyrX+A95ELLuDMQ== alanchan@server2
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAwew/f2FAVoMnDkZ5yD9YGDMzDLNOciO77B4r70mIEb/mUgZQLncyRbU7zecR4W/gi7u8oq7oVfHSAVKOJneR28Hyk8Icb875y3RO6I9gFOfwID3Qs8TFtXPyCZBtfEeTRWjYtRs/GjF42UeBTeLDn4Y5uHKxe+IAWywRYCTR/ke9Gis4yXbN8fw2I4lkLV2hon4Id2yZsYCK8U8DPcMLZ2aRgowkQ3T/TrBwcFZskUH4sUYqZ3L7G5y4x0hpf2nTcpay1UwyBsryErdcFYoc64Ev/cwyubAmvHy4eZEHIY3S55j4p6tB9TnvkCRJst6v3NzVw1dA2RMZP76blPso9w== alanchan@server3
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAtWzosBg6f6k2pZp7Kt2mjJ3VgUVbdpr/XCIvYAVTKtk5QmFioc9IH8hODRZB2+R6+GiRY0u09LwKhcPOyEngNDtLbas8ACigCFgTyA7jG/eCEs6MO3oxVBgsiyNnvhAJnQS7cYG+gp46B2b/X4dCW9QEoYrV9r0ZAejWXFMHWMw5V3vDA69SJvLfoBoZfvT8C48g1XpEI0me1X+6KpDQk+1CZu4nA1NSmytxbl9OmcoxDo2ywLtclycjfhKfKUYL7uBXNT8oiUbwUc6RTme5WC0sU3oTvQLcHbQjR218+LZi74xszWssRuJmrUlc0zZy/6GjsK2pIieO7Iq5lq9uBQ== alanchan@server45、将server1上authorized_keys的文件复制到server2、server3、server4上
如此可以做到server1到server4的双向免密登录。如果是单向免密登录，这步可以不做。
[alanchan@server1 .ssh]$ scp ~/.ssh/authorized_keys alanchan@server2:~/.ssh/
alanchan@server2's password:
authorized_keys 100% 1592 1.6KB/s 00:00
[alanchan@server1 .ssh]$ scp ~/.ssh/authorized_keys alanchan@server3:~/.ssh/
alanchan@server3's password:
authorized_keys 100% 1592 1.6KB/s 00:00
[alanchan@server1 .ssh]$ scp ~/.ssh/authorized_keys alanchan@server4:~/.ssh/
alanchan@server4's password:
authorized_keys 100% 1592 1.6KB/s 00:00
[alanchan@server1 .ssh]$ ll
总用量 28
-rw-r--r-- 1 alanchan root 1592 9月 8 14:06 authorized_keys
-rw------- 1 alanchan root 1671 9月 8 13:40 id_rsa
-rw-r--r-- 1 alanchan root 398 9月 8 13:40 id_rsa.pub
-rw-r--r-- 1 alanchan root 2805 9月 7 09:07 known_hosts
-rw-r--r-- 1 alanchan root 398 9月 8 14:03 server2.id_rsa.pub
-rw-r--r-- 1 alanchan root 398 9月 8 14:04 server3.id_rsa.pub
-rw-r--r-- 1 alanchan root 398 9月 8 14:05 server4.id_rsa.pub6、在四台机器上都操作，进行文件夹授权
[alanchan@server1 ~]$ chmod 700 ~/.ssh
[alanchan@server1 ~]$ chmod 600 ~/.ssh/authorized_keys7、验证
在server1上测试连接server2、server3、server4的免密登录情况
[alanchan@server1 ~]$ ssh server2
Last login: Thu Sep 8 13:54:04 2022 from 192.168.3.105
[alanchan@server2 ~]$ exit
logout
Connection to server2 closed.
[alanchan@server1 ~]$ ssh server3
Last login: Thu Sep 8 13:54:27 2022 from 192.168.3.105
[alanchan@server3 ~]$ exit
logout
Connection to server3 closed.
[alanchan@server1 ~]$ ssh server4
Last login: Thu Sep 8 05:54:48 2022 from 192.168.3.105
[alanchan@server4 ~]$ exit
注销
Connection to server4 closed.以上完成后，免密登录完成。
