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When users upgrade an existing MM2 cluster they don’t need to change any of their current configuration as this proposal maintains the default behaviour for MM2.

Rejected Alternatives

1- Use the ReplicationPolicy and replication.policy.separator to control the naming convention for internal topics. Reason to reject: Since not all of the internal topics are not replicated it makes more sense to control them from a different interface.

2- Add a configuration for each topic however this would add more complexity for the implementation and more fields to MirrorMaker 2 config, also we will need to find a way to identify if topic is checkpoints for MirrorMaker utils and away to identify if topic is internal topic for MirrorCheckpointTask and MirrorSourceConnector to make sure we not track checkpoint or replicate them.