怎樣部署ssh免密鑰登陸

SSH免密鑰登陸其實很簡單，只需幾步就能部署完成。
測試環境：CentOS Linux release 7.1.1503 (Core)
步驟以下：
1. 在主機上生成公鑰和密鑰！
[ Thegod:~ chengde$ ssh-keygen #一直回車便可！
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/chengde/.ssh/id_rsa):
/Users/chengde/.ssh/id_rsa already exists.
...

2. 第一步執行完成後，會在你當前登陸的用戶的宿主目錄下生成一個.ssh的目錄，在.ssh目錄下會生成兩個文件（id_rsa和id_rsa.pub）私鑰和公鑰

Thegod:~ chengde$ cd .ssh/
Thegod:.ssh chengde$ ls
id_rsa id_rsa.pub known_hosts

3. 將公鑰（id_rsa.pub)移動到要免密碼登陸的服務器的用戶家目錄下的.ssh目錄下並更名爲authorized_keys
Thegod:.ssh chengde$ ssh-copy-id -i ~/.ssh/id_rsa.pub root@103.40.101.59
Remarks: 若是須要免密鑰登陸的服務器的用戶家目錄下的.ssh目錄下已經有authorized_keys這個文件了，那麼就將公鑰追加到這個文件中，若是覆蓋了裏面的內容就更改了！（此內容只適合多臺服務器免密鑰登陸這臺服務器）

4.測試，完成

Thegod:.ssh chengde$ ssh root@103.40.101.59
Last failed login: Sun Jan 28 21:13:04 CST 2018 from 218.65.30.30 on ssh:notty
There were 883 failed login attempts since the last successful login.
Last login: Sun Jan 28 20:30:20 2018 from 139.215.216.12
[root@server59 ~]#