php-fpm Bad file descriptor errors

Solution 1:

Increased:

pm.max_children = 20
pm.min_spare_servers = 2
pm.max_spare_servers = 4
request_terminate_timeout = 300s
request_slowlog_timeout = 300s

and all problems are gone ;)

Solution 2:

I managed to fix this issue by correcting file permissions on the logs.

Make sure your configured log files are both readable and writable by the user running php-fpm.