Since `KafkaController.incrementControllerEpoch()` will always print controllerContext.epochZkVersion, the only extra information we are seeking here is the current zkversion of the controller epoch znode. It seems that we only need this information when the broker observes ControllerMovedException when it thinks it is controller. Since `Reelect` is triggered in every broker every time there is controller movement, it may not be very intuitive or necessary to print the extra log here in `Relect.process()`.
Another thing to note that that we would like to know the zkversion of the controller epoch znode that causes the ControllerMovedException, but this zk version may have changed after the controller observes ControllerMovedException but before the controller processes Reelect event. So it is better to read the zkversion earlier (e.g. in `ControllerEventThread.doWork()`) than later. The best solution is probably to include the expected zkversion in the message of `ControllerMovedException` thrown by `maybeThrowControllerMoveException()`. [ Full content available at: https://github.com/apache/kafka/pull/5101 ] This message was relayed via gitbox.apache.org for [email protected]
