Handing 15,000+ SSL certs and nginx configuration

Hello All,

I am running an application that has about 200,000 subdomains and 15,000 custom domains. Each subdomain belongs to a customer and they have an ability to white label my platform by using their own ‘custom domains'

I currently have only 1 nginx configuration file to serve all of these domains. I make use of $http_name variable to dynamically define my websites within single nginx virtual host config but I’d like to implement SSL certificate on all of them.

200,000 subdomains are easy because I can get away with couple of lines of code with a wildcard certificate.

My problem is custom domains. These 15,000 unique domains requires SSL cert and I implemented Let’s encrypt to generate certificate for all of them. It works properly so far.

Here is my question:

My understanding is that I cannot use variables in file paths. Therefore, to be able to point 15k domain to proper SSL cert, I need to create 15,000 nginx configuration. It’s going to be very hard to manage. What can I do to overcome this problem? Is there any other easy way?