轉載：http://www.jb51.net/article/94599.htm
1.Linux下生成密鑰ssh-keygen的指令手冊，通過”man ssh-keygen“指令：
通過指令”ssh-keygen -t rsa“
生成之後會在使用者的根目錄生成一個 “.ssh”的檔案夾
進入“.ssh”會生成以下幾個檔案
authorized_keys:存放遠端免密登入的公鑰,主要通過這個檔案記錄多台機器的公鑰
id_rsa : 生成的私鑰檔案
id_rsa.pub ： 生成的公鑰檔案
know_hosts : 已知的主機公鑰清單
如果希望ssh公鑰生效需滿足至少下面兩個條件：
1) .ssh目錄的權限必須是700
2) .ssh/authorized_keys檔案權限必須是600
2.遠端免密登入原理圖：
指令： ssh-copy-id -i ~/.ssh/id_rsa.put
舉例：
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[[email protected]]# ssh-copy-id -i ~/.ssh/id_rsa.pub 192.168.91.135
[email protected]'s password:
Now try logging into the machine, with "ssh '192.168.91.135'", and check in:
.ssh/authorized_keys
to makesure we haven't added extra keys that you weren't expecting.
[[email protected]]# ssh [email protected]
Last login: Mon Oct 10 01:25:49 2016 from 192.168.91.133
[root@localhost ~]#
常見錯誤：
[root@test ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub 192.168.91.135
-bash: ssh-copy-id: command not found //提示指令不存在
解決辦法：yum -y install openssh-clients
2.2 通過scp将内容寫到對方的檔案中
指令：scp -p ~/.ssh/id_rsa.pub root@:/root/.ssh/authorized_keys
舉例：
[[email protected]]# scp -p ~/.ssh/id_rsa.pub [email protected]:/root/.ssh/authorized_keys
id_rsa.pub 100% 408 0.4KB/s00:00
Last login: Mon Oct 10 01:27:02 2016 from 192.168.91.133
也可以分為兩步操作：$ scp ~/.ssh/id_rsa.pub root@:pub_key //将檔案拷貝至遠端伺服器
$ cat ~/pub_key >>~/.ssh/authorized_keys //将内容追加到authorized_keys檔案中， 不過要登入遠端伺服器來執行這條指令
2.3 通過Ansible實作批量免密 2.3.1 将需要做免密操作的機器hosts添加到/etc/ansible/hosts下：[Avoid close]
192.168.91.132
192.168.91.133
192.168.91.134
2.3.2 執行指令進行免密操作ansible -m authorized_key -a "user=root key='{{ lookup('file','/root/.ssh/id_rsa.pub') }}'" -k
示例：
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[[email protected]]# ansible test -m authorized_key -a "user=root key='{{ lookup('file','/root/.ssh/id_rsa.pub') }}'" -k
SSH password: ----->輸入密碼
192.168.91.135 | success >> {
"changed": true,
"key": "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEArZI4kxlYuw7j1nt5ueIpTPWfGBJoZ8Mb02OJHR8yGW7A3izwT3/uhkK7RkaGavBbAlprp5bxp3i0TyNxa/apBQG5NiqhYO8YCuiGYGsQAGwZCBlNLF3gq1/18B6FV5moE/8yTbFA4dBQahdtVP PejLlSAbb5ZoGK8AtLlcRq49IENoXB99tnFVn3gMM0aX24ido1ZF9RfRWzfYF7bVsLsrIiMPmVNe5KaGL9kZ0svzoZ708yjWQQCEYWp0m+sODbtGPC34HMGAHjFlsC/SJffLuT/ug/hhCJUYeExHIkJF8OyvfC6DeF7ArI6zdKER7D8M0SM WQmpKUltj2nltuv3w== [email protected]",
"key_options": null,
"keyfile": "/root/.ssh/authorized_keys",
"manage_dir": true,
"path": null,
"state": "present",
"unique": false,
"user": "root"
}
2.4 手工複制粘貼的方式将本地id_rsa.pub檔案的内容拷貝至遠端伺服器的~/.ssh/authorized_keys檔案中