ssh客户端无需输入密码登录服务器

原来通过ssh client登录服务器时：

$ ssh root@192.168.1.100
root@192.168.1.100's password:

是需要登录用户输入密码的，如果密码强度设置得比较高的话，还是不太容易记忆的。每次登录前都得把密码记录翻出来看看，工作效率不是很高。

为了提高效率，我们可以在本地（client端）生成一个私钥，一个公钥。

$ cd ~/.ssh

$ ssh-keygen

Generating public/private rsa key pair.
Enter file in which to save the key (/Users/simon/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/simon/.ssh/id_rsa.
Your public key has been saved in /Users/simon/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:aleqVoG5ecZ*****************qWkWaO0BTRG8 simon@Simon.local
The key's randomart image is:
+---[RSA 2048]----+
|       ++.       |
|      B o.+      |
|     * @ BEo     |
|    = O O.= o    |
|   . + XSB.o     |
|    o +.@o.      |
|   o  o*oo       |
|  .  .oo         |
|     ..          |
+----[SHA256]-----+

$ ls
config				id_rsa.pub			
id_rsa				known_hosts

然后登录到远程服务器，在~/.ssh目录下新建authorized_keys文件。

$ touch ~/.ssh/authorized_keys

把公钥（client端）的~/.ssh/id_rsa.pub文件的内容复制到服务器的.ssh/authorized_keys里面保存着。

这时，当你通过ssh root@192.168.1.100登录服务器时，就已经不需要输入密码了。