At the moment the server log (bitbake-cookerdaemon.log in the build directory) is just a stream of messages and there's no separation between different instances over time. This makes it hard to see which messages are associated with the latest instance, particularly if you're trying to diagnose a startup failure - worse still if the client prints the last 10 lines and some of those lines are unrelated.

We should write a separator when the server starts logging to the file, and also log the date and time as the first entry (probably within the existing "starting bitbake server pid ..." line). The separator should be programmatically identifiable in such a way that it is very unlikely that a normal error message could be mistaken for the separator, and we should then change the code that prints the last 10 (or however many) lines of the log to find the last separator reliably and only print back to that point.