Adds doc for HAproxy

examples/haproxy/README.md

@@ -0,0 +1,25 @@
+# HAproxy reverse-proxy
+
+This directory contains sample files that show you how to do reverse-proxying using HAproxy.
+
+This is for when you wish to have your own HAproxy instance sitting in front of Matrix services installed by this playbook.
+See the [Using your own webserver, instead of this playbook's nginx proxy](../../docs/configuring-playbook-own-webserver.md) documentation page.
+
+To use your own HAproxy reverse-proxy, you first need to disable the integrated Nginx server.
+You do that with the following custom configuration (`inventory/host_vars/matrix.<your-domain>/vars.yml`):
+
+```yaml
+matrix_nginx_proxy_enabled: false
+```
+
+You can then use the configuration files from this directory as an example for how to configure your HAproxy reverse proxy.
+
+**NOTE**: this is just an example and may not be entirely accurate. It may also not cover other use cases or performance needs.
+
+### Configuration
+
+HAproxy, unlike Apache, Nginx and others, does not provide you with a webserver to serve static files (i.e., `/.well-known/` directory). For this reason, in this folder you can find an example on how to use HAproxy together with a simple Nginx container whose only task is to serve those files.
+
+* Build the Docker image. `docker build -t local/nginx .` 
+* Start the container. `docker-compose up -d`. Note that if you want to run Nginx on a different port, you will have to change the port both in the `docker-compose.yml` and in `haproxy.cfg` files.
+* Start HAproxy with the proposed configuration.