Unexpected error in the timer
An error appeared a few days back with the bot (I do not have the log the day it appeared anymore) :
Sep 6 17:23:09 hastur python3[6846]: 2018-09-06 17:23:09,048 - CRITICAL - Unexpected error in the timer: "[Errno 24] Too many open files: '/home/john/dnsresolver/dns-bot-ekm0yvn0.heartbeat'"
Sep 6 17:23:09 hastur python3[6846]: 2018-09-06 17:23:09,549 - CRITICAL - Unexpected error in the timer: "[Errno 24] Too many open files: '/home/john/dnsresolver/dns-bot-62xetzjx.heartbeat'"
Sep 6 17:23:10 hastur python3[6846]: 2018-09-06 17:23:10,050 - CRITICAL - Unexpected error in the timer: "[Errno 24] Too many open files: '/home/john/dnsresolver/dns-bot-n5xoq__d.heartbeat'"
Sep 6 17:23:10 hastur python3[6846]: 2018-09-06 17:23:10,551 - CRITICAL - Unexpected error in the timer: "[Errno 24] Too many open files: '/home/john/dnsresolver/dns-bot-664xtfzr.heartbeat'"
Sep 6 17:23:11 hastur python3[6846]: 2018-09-06 17:23:11,052 - CRITICAL - Unexpected error in the timer: "[Errno 24] Too many open files: '/home/john/dnsresolver/dns-bot-v6smg4qz.heartbeat'"
Sep 6 17:23:11 hastur python3[6846]: 2018-09-06 17:23:11,553 - CRITICAL - Unexpected error in the timer: "[Errno 24] Too many open files: '/home/john/dnsresolver/dns-bot-f8z5uswb.heartbeat'"
Sep 6 17:23:12 hastur python3[6846]: 2018-09-06 17:23:12,055 - CRITICAL - Unexpected error in the timer: "[Errno 24] Too many open files: '/home/john/dnsresolver/dns-bot-k5prfiqv.heartbeat'"
None of these heartbeat files seem to exist. A restart of the service I use to manage the bot did the trick to stop this bug