Document custom Nginx configuration in README.md

README.md

@@ -114,3 +114,36 @@ In order to be able to securize your virtual host, you have to create a file nam
     $ docker run -d -p 80:80 -p 443:443 -v /path/to/htpasswd:/etc/nginx/htpasswd -v /path/to/certs:/etc/nginx/certs -v /var/run/docker.sock:/tmp/docker.sock jwilder/nginx-proxy
 
 You'll need apache2-utils on the machine you plan to create de htpasswd file. Follow these [instructions](http://httpd.apache.org/docs/2.2/programs/htpasswd.html)
+
+### Custom Nginx Configuration
+
+If you need to configure Nginx beyond what is possible using environment variables, you can provide custom configuration files on either a proxy-wide or per-`VIRTUAL_HOST` basis.
+
+#### Proxy-wide
+
+To add settings on a proxy-wide basis, add your configuration file under `/etc/nginx/conf.d` using a name ending in `.conf`.
+
+This can be done in a derived image by creating the file in a `RUN` command or by `COPY`ing the file into `conf.d`:
+
+```Dockerfile
+FROM jwilder/nginx-proxy
+RUN { \
+      echo 'server_tokens off;'; \
+      echo 'client_max_body_size 100m;'; \
+    } > /etc/nginx/conf.d/my_custom_proxy.conf
+```
+
+Or it can be done by mounting in your custom configuration in your `docker run` command:
+
+    $ docker run -d -p 80:80 -p 443:443 -v /path/to/my_custom_proxy.conf:/etc/nginx/conf.d/my_custom_proxy.conf:ro -v /var/run/docker.sock:/tmp/docker.sock jwilder/nginx-proxy
+
+#### Per-VIRTUAL_HOST
+
+To add settings on a per-`VIRTUAL_HOST` basis, add your configuration file under `/etc/nginx/vhost.d`. Unlike in the proxy-wide case, which allows mutliple config files with any name ending in `.conf`, the per-`VIRTUAL_HOST` file must be named exactly after the `VIRTUAL_HOST`.
+
+In order to allow virtual hosts to be dynamically configured as backends are added and removed, it makes the most sense to mount an external directory as `/etc/nginx/vhost.d` as oppposed to using derived images or mounting individual configuration files.
+
+For example, if you have a virtual host named `app.example.com`, you could provide a custom configuration for that host as follows:
+
+    $ docker run -d -p 80:80 -p 443:443 -v /path/to/vhost.d:/etc/nginx/vhost.d:ro -v /var/run/docker.sock:/tmp/docker.sock jwilder/nginx-proxy
+    $ { echo 'server_tokens off;'; echo 'client_max_body_size 100m;'; } > /path/to/vhost.d/app.example.com