I have a fresh install of Debian Stretch with all updates and Knot Resolver 1.4.0. installed from CZ.NIC repositories. I've set up a rather simple configuration allowing our users to use the resolver and everything works fine (systemd socket override for listening on LAN). I have however noticed that kresd logs every single query into /var/log/syslog, generating approx. 1 MB/min worth of logs on our server. I've looked into documentation and haven't found any directive to control the logging behavior. Is there something I might be missing? I would preferrably like to see only warnings in the log.

Apparently kresd is in "verbose" mode.  That can be triggered by `-v/--verbose` command-line parameter or even by `verbose(true)` in configuration.  I suspect there's a forgotten flag somewhere, perhaps in the packaging.  For now, adding `verbose(false)` to your configuration should work around that.

--Vladimir