Looking at and thinking about:

https://bugzilla.yoctoproject.org/show_bug.cgi?id=5187

We have several issues. Firstly, DATE and TIME are locked in stone when
the base configuration is parsed. This may cause images to overwrite
previous versions for example if DATE and TIME are not re-evaluated. We
could fix this by specifically setting DATE and TIME in bitbake at
BuildStart?

Secondly, there is one cooker log file opened for the duration of the
cooker lifecycle. This is a cooker log, not a log of each build so that
is perhaps not surprising (and is the core problem in the above bug).
There is no overwriting of the log file, it just keeps growing with each
build.

We could trigger knotty to write out build specific log files based on
the BuildStart/Finish events?