In this post we will see a case study of a Galera Cluster migration to AWS Aurora and quick solution to the replication issue.
A friend received an error in a Master-Master replication as follows:
Could not execute Write_rows event on table _database._table; Duplicate entry '65eJ8RmzASppBuQD2Iz73AAy8gPKIEmP-2018-08-03 08:30:03' for key 'PRIMARY', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log mysql-bin-changelog.000010, end_log_pos 1107814
We talked about it and I immediately started blabbering cons of writing on both masters, how to handle, roles of apps and so on. He intervened and revealed, it is Galera Cluster replicated to Aurora and he is not writing on Aurora.
He was actually migrating his Galera Cluster to Aurora and master-master was to support his rollback plans. Consider following diagram for simplicity of understanding: