> A solution I use is to delay next reload in systemd unit until a > reload is in progress.
Unfortunately, even when doing this you can end up in the situation described before, because for systemd a reload is basically a SIGUSR2 to send. You do not wait for some callback saying "I'm now OK and fully reloaded" (if I'm wrong, I could be interested in your systemd setup). I naively tried such approach by adding a grace period of 2s (sleep) and avoid to send another reload during that period, but at some point you'll encounter the same issue when upstream contention will be higher (meaning that you'll have ton of things to reload, you'll then add delay and decrease real-time aspect of your solution etc etc).
