http: Accept error: accept tcp [::]:9253: accept4: too many open files;

[PhilMakower]

I am running php-fpm_exporter on my servers, one of which has a LOT of pools since it is running a lot of websites (48)
The exporter will stop responding after a while, and the logs contain errors as in the title.

May be something like prometheus/blackbox_exporter#288

[itcsoft54]

It seems like you hit fd limitation on your system or inside the container (if you use containerized version of exporter).
You can check with ulimit command or limits.conf file outside for system limitation (with the same user you're using for running containers) or inside container (with root and same user you're using for running)

You can use lsof to check currently open file by exporter

Default limit are 1024 for some Linux distribution. Maybe you need to increase this limit up to your needs.