The setup I need to build with HAProxy is the high availability solution consisting of http (http to https redirection must be configured in HAProxy) and https frontends with two backends. Backend servers have HTTPS enabled so HAProxy must establish HTTPS connection to backend servers. We have four backend servers and we want first two servers serve one specific app (/app path) and the other two – all other requests so we need path-based routing in HAProxy. In addition, there are multiple domains that must be served by backend servers (and HAProxy).

As we need path-based routing, HAProxy must operate in http mode (on the 7th level) allowing it to examine contents of HTTP headers and extract Host and Path headers. Later, the incoming request must be sent to a proper backend based on the Path header and connection to backend server must be established via HTTPS. As multiple domains must be served by HAProxy and backends we need to install multiple certificates in HAProxy and enable Server Name Indication (SNI) with backend servers.

Here is how configure HAProxy in that way step by step. Continue reading