nginx reverse ssl proxy with multiple subdomains

I'm trying to locate a high level configuration example for my current situation. We have a wildcard SSL certificate for multiple subdomains which are on several internal IIS servers.

site1.example.com (X.X.X.194) -> IISServer01:8081
site2.example.com (X.X.X.194) -> IISServer01:8082
site3.example.com (X.X.X.194) -> IISServer02:8083

I am looking to handle the incoming SSL traffic through one server entry and then pass on the specific domain to the internal IIS application. It seems I have 2 options:

1. Code a location section for each subdomain (seems messy from the examples I have found)

2. Forward the unencrypted traffic back to the same nginx server configured with different server entries for each subdomain hostname. (At least this appears to be an option).

My ultimate goal is to consolidate much of our SSL traffic to go through nginx so we can use HAProxy to load balance servers.

Will approach #2 work within nginx if I properly setup the proxy_set_header entries?

I envision something along the lines of this within my final config file (using approach #2):

server {
  listen Y.Y.Y.174:443; #Internally routed IP address
  server_name *.example.com;

  proxy_pass http://Y.Y.Y.174:8081;
}

server {
  listen Y.Y.Y.174:8081;
  server_name site1.example.com;

  -- NORMAL CONFIG ENTRIES --

  proxy_pass http://IISServer01:8081;
}

server {
  listen Y.Y.Y.174:8081;
  server_name site2.example.com;

  -- NORMAL CONFIG ENTRIES --

  proxy_pass http://IISServer01:8082;
}

server {
  listen Y.Y.Y.174:8081;
  server_name site3.example.com;

  -- NORMAL CONFIG ENTRIES --

  proxy_pass http://IISServer02:8083;
}

This seems like a way, but I'm not sure if it's the best way. Am I missing a simpler approach to this?

Solution 1:

I would do something like this (tested with nginx 1.4.2, seems to work):

server {
  listen 127.0.0.1:443 ssl;
  server_name site1.example.com;

  include common.conf;

  location / {
    proxy_pass http://127.0.0.2:8081;
  }
}

server {
  listen 127.0.0.1:443 ssl;
  server_name site2.example.com;

  include common.conf;

  location / {
    proxy_pass http://127.0.0.2:8082;
  }
}

server {
  listen 127.0.0.1:443 ssl;
  server_name site3.example.com;

  include common.conf;

  location / {
    proxy_pass http://127.0.0.3:8083;
  }
}

With at least this in common.conf:

ssl on;
ssl_certificate  /path/to/cert;
ssl_certificate_key  /path/to/key;

Solution 2:

Believe it or not, you can do this:

ssl_session_cache shared:SSL:2m;
ssl_session_timeout 5m;

server {
    listen Y.Y.Y.174:443 default_server ssl;
    server_name _;
    ssl_certificate /etc/pki/tls/certs/server.chained.crt;
    ssl_certificate_key /etc/pki/tls/private/server.key;
}

server {
    listen Y.Y.Y.174:443 ssl;
    server_name site1.example.com;
    [...]
    proxy_pass http://IISServer01:8081;
}

server {
    listen Y.Y.Y.174:443 ssl;
    server_name site2.example.com;
    [...]
    proxy_pass http://IISServer01:8082;
}

server {
    listen Y.Y.Y.174:443 ssl;
    server_name site3.example.com;
    [...]
    proxy_pass http://IISServer02:8083;
}

No includes, the certificate is loaded into memory just once, and the session should even stay cached as the user moves from subdomain to subdomain, saving you plenty of handshake horsepower.

I can't find any documentation beyond this Server Fault post to suggest why this works, but I can assure you that it does.