Using Certbot with Knot DNS (knsupdate)

This is a note about the integration of the Certbot with Let’s encrypt DNS–01 authentication mechanism. Will not use any cloud services (fuck cloud), just self-hosted DNS instances, like good old times. I’ll show how to configure Knot DNS to accept dynamic DNS updates from knsupdate and how to create a rudimentary hook for Certbot which will use knsupdate to set TXT records with _acme-challenge.