php-fpm and other middleware prometheus monitoring

we have a couple of things like gunicorn and php-fpm out there that bridge our frontend proxies (nginx/apache) and the backend code (django, Drupal/CiviCRM...), yet we have no resource monitoring on those things. like the webservers in front of them, they have specific scalibility needs like number of parallel processes, read queues and so on...

i didn't think much about this before finding https://github.com/Lusitaniae/phpfpm_exporter in FreeBSD ports, but now i wonder if that's something we should keep an eye on somehow.

low priority, obviously.