I'm about to embark on creating 12000 vhosts

[rick_pri]

Our current setup is pretty simple, we have a regex capture to ensure that
the incoming request is a valid ascii domain name and we serve all our
traffic from that.  Great ... for us.

However, our customers, with about 12000 domain names at present have
started to become quite vocal about having HTTPS on their websites, to which
we provide a custom CMS and website package, which means we're about to
create a new Nginx layer in front of our current servers to terminate TLS. 
This will require us to set up vhosts for each certificate issued with
server names which match what's in the certificate's SAN.

To keep this simple we're currently thinking about just having each domain,
and www subdomain, on its own certificate (LetsEncrypt) and vhost but that
is going to lead, approximately, to the number of vhosts mentioned in the
subject line.  As such I wanted to put the feelers out to see if anyone else
had tried to work with large numbers of vhosts and any issues which they may
have come across.

Kind regards,

Richard

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,282986,282986#msg-282986