I have setup a master and slave MySQL running 5.7.17 in Linux machines. Both servers have a unique UUID as specified in the auto.cnf file. Besides, the master server has server-id=10 while slave has server-id=20.
However I keep getting the following error coming in the master's error log. I could not figure out why as the replication is running fine. The error starts to come out when the master's SQL thread is stopped.
2016-12-28T09:00:37.953467Z 27931 [Note] Start binlog_dump to master_thread_id(27931) slave_server(20), pos(hostnameA-bin.000117, 818913948)
2016-12-28T09:01:38.027487Z 27978 [Note] While initializing dump thread for slave with UUID <xxxxxxxx-xxx-xxxx-8bbc-xxxxxxxxxxxx>, found a zombie dump thread with the same UUID. Master is killing the zombie dump thread(27931).
2016-12-28T09:01:38.027652Z 27978 [Note] Start binlog_dump to master_thread_id(27978) slave_server(20), pos(hostnameA-bin.000117, 818913948)
2016-12-28T09:02:38.104298Z 28025 [Note] While initializing dump thread for slave with UUID <xxxxxxxx-xxx-xxxx-8bbc-xxxxxxxxxxxx>, found a zombie dump thread with the same UUID. Master is killing the zombie dump thread(27978).