1. 安装CertBot
$ sudo yum install certbot python2-certbot-nginx
参考官方网址：https://certbot.eff.org/lets-encrypt/centosrhel7-nginx
2. 手动模式
2.1 输入命令：
$ certbot certonly --preferred-challenges dns --manual -d *.cncaq.com --server https://acme-v02.api.letsencrypt.org/directory
参数说明：
- --preferred-challenges dns: 认证方式选择DNS, 泛域名支持DNS
- --manual: 手动模式, 这里为了简单就使用手动认证了, 下面会说自动模式的使用.
- -d *.cncaq.com: 就是要申请的泛域名了
- --server https://acme-v02.api.letsencrypt.org/directory: 泛域名证书是新功能, 如果要使用就得加上这个参数
2.2 敲下回车：
-------------------------------------------------------------------------------
NOTE: The IP of this machine will be publicly logged as having requested this
certificate. If you're running certbot in manual mode on a machine that is not
your server, please ensure you're okay with that.
Are you OK with your IP being logged?
-------------------------------------------------------------------------------
(Y)es/(N)o: y
2.3 再敲下y：
-------------------------------------------------------------------------------
Please deploy a DNS TXT record under the name
_acme-challenge.cncaq.com with the following value:
W2Z_PT1RQX8usavprZ1ly43Je2ayst3ShIBxpgicdEA
Before continuing, verify the record is deployed.
-------------------------------------------------------------------------------
2.4 在阿里云控制台的域名解析服务中添加一个泛解析：
2.5 按下回车
Waiting for verification...
Cleaning up challenges
IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at:
/etc/letsencrypt/live/cncaq.com/fullchain.pem
Your key file has been saved at:
/etc/letsencrypt/live/cncaq.com/privkey.pem
Your cert will expire on 2020-07-16. To obtain a new or tweaked
version of this certificate in the future, simply run certbot
again. To non-interactively renew *all* of your certificates, run
"certbot renew"
- If you like Certbot, please consider supporting our work by:
Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
Donating to EFF: https://eff.org/donate-le
https://www.jianshu.com/p/1eb7060c5ede
https://blog.csdn.net/wc810267705/article/details/79917688
https://www.jianshu.com/p/43e74cddba45
https://www.jianshu.com/p/2c1de124d994