Major Description
Due to a previous CDH-1444 (fix flume node heartbeat hangs with bad configuration) we changed the semants of starting a logical node to force opens into the driver thread by making open lazy. This broke an invariant – a unopenable logical node (due to source or sink) would be recorded as the last good config. If a config failed, the default behavior was to revert to previous last good – which was the broken configuration. There was no throttling, so this would eventaully eat up file handles if they were not cleaned and spin up a lot of threads.