If I create a master database by itself

docker-compose up -d

Then connect to this database and load in some initial content. I have two databases. One is about .5Gb the other about 1Gb.

Then when I try to create a slave

docker-compose scale mysql=2

The replication fails with a line about Can't create database because it exists. I'm guessing this is maybe a race condition between the initial backup and replication starting. I've reproduced this scenario twice in a row.