TL;DR: Make sure to run “SET persist_only disabled_storage_engines=’MyISAM’, persist sql_generate_invisible_primary_key=ON;” on all instances and restart each one in your MySQL InnoDB Cluster.

Ok, what does “safe from naughtiness” mean?:
– Anyone creating tables that aren’t InnoDB, as this doesn’t make sense, after all, it is an “InnoDB” cluster.
– Making sure all tables have a Primary Key (invisible or not).
– Making sure that my (invisible) primary keys are visible to the cluster as it will rightfully complain if they aren’t!

This basically means that once you’ve got it all up and running you won’t run into those horrible situations whereby someone, somewhere, creates a MyISAM table that didn’t have a Primary Key and thus leave you with a broken cluster.

Eg.

MySQL rtnode-01:3306 ssl JS > vlc.status()
{
 "clusterName": "VLC",
 "clusterRole": "PRIMARY", …