Landmark “corporate” technical blog post from Willy Tarreau titled “Truly Seamless Reloads with HAProxy – No More Hacks!”
Summary is that there is progress concerning HAProxy zero-downtime reloads on linux, even under heavy connection load.
Interestingly, microservice owners doing frequent updates and reloads have been driving the interest behind this.
Thanks to Willy for both the improvements, and the very detailed (and lengthy) blog post explaining the history and status of the fixes.