See containers/conmon#84.
Basically, no matter how good a log scraper is, if it can't keep up with the rate at which logs are written (through no fault of its own), log rotation will cause significant log loss.
Either one has to accept log loss, or we can fix the inherent problems with container logging as described in containers/conmon#84.
One also needs to fix container run times to write logs in a reasonable manner (not interpreting the byte stream, that is for the log reader, or later, to do), see containers/conmon#265.