输入命令：ssh-keygen -t rsa，一路enter

[root@VM-4-8-centos git]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:GroNNcshlP+ydiQlig0LuhZ1jy3YRG+ufV7hmtdU0zs root@VM-4-8-centos
The key's randomart image is:
+---[RSA 2048]----+
|                 |
|     o           |
|    + .         .|
|. .o +.o.      o.|
|...=*.%oS  .  . o|
|..o.oO.@. . .. E |
| .. o Oo.  oo   .|
|..   =.+..+. .   |
|.   ..o.o+.      |
+----[SHA256]-----+
[root@VM-4-8-centos git]#