motd (message of the day) in kea
We could implement a message in Kea, the if configured, would be logged when Kea is started or reconfigured. Trivial to implement.
This would be useful in Docker. We need to put some config file in a Docker image, with the expectation that the user will replace it with a real config. If the user doesn't, Kea should start, but print something like "please edit your config file, map your volume when starting Docker image, etc.". The text would be configurable in a config file.
This is similar to Unix idea of /etc/motd
(its content is printed as a welcome message to the user every time he/she logs in).