准备epel源
yum -y install epel
直接yum安装
yum -y install certbot
申请证书，期间需要去dns解析页面配置TXT解析
certbot certonly --email 532733691@qq.com --server https://acme-v02.api.letsencrypt.org/directory --agree-tos --manual --preferred-challenges=dns -d *.xx.com
查看生成的公钥私钥
ll /etc/letsencrypt/live/xx.com/fullchain.pem #公钥
ll /etc/letsencrypt/live/xx.com/privkey.pem #私钥
借鉴https://www.zhihu.com/question/484431835/answer/3163134184?utm_id=0