HAProxy instructions will be included in the expanded HA guide by CF 5.0 or earlier. As we've reformed the current HA guide into instructions for the database tier only, the HAProxy instructions were removed temporarily. The plan is to put these instructions (and more) into a section on configuring the UI tier. Since it will take some time to gather this info and form the content, and some internal customers have been asking about the HAProxy instructions, we've agreed (docs team/engineering) to put this into a Kbase article for now.
The article is live on the Customer Portal: https://access.redhat.com/articles/2967461