Thank you for your post, just a couple of quick questions

• What is your use case for choosing HAProxy over ELB? I’ve used both for many years and ELB works very well, also if you know how much traffic you have you can totally avoid the “DDOS” issue by pre-warming the ELB.
• Your cron runs every 3 min that means as you wrote, you will drop connection and it’s very problematic in any application to happen.

HAProxy is a great piece of software that has been around for year but today you have great alternatives that offer the same speed if not more, are more flexible and simpler to use, my preferred option these days is Traefik I recommend you check it out.