yum install epel-release -y && yum makecache fast yum install certbot -y
certbot certonly -d mg2.98hg.top --preferred-challenges http --server https://acme-v02.api.letsencrypt.org/directory
certbot certonly -d mg2.98hg.top --preferred-challenges http --server https://acme-v02.api.letsencrypt.org/directory 交互过程