[KAFKA-12254] MirrorMaker 2.0 creates destination topic with default configs

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.4.0, 2.5.0, 2.4.1, 2.6.0, 2.5.1, 2.7.0, 2.6.1, 2.8.0
• Fix Version/s: 2.8.0
• Assignee: Dhruvil Shah
• Reporter: Dhruvil Shah
• Reviewer: Rajini Sivaram
• Created: 29/Jan/21 20:06
• Updated: 02/Mar/21 22:37
• Resolved: 01/Mar/21 09:33

Description

`MirrorSourceConnector` implements the logic for replicating data, configurations, and other metadata between the source and destination clusters. This includes the tasks below:

1. `refreshTopicPartitions` for syncing topics / partitions from source to destination.
2. `syncTopicConfigs` for syncing topic configurations from source to destination.

A limitation is that `computeAndCreateTopicPartitions` creates topics with default configurations on the destination cluster. A separate async task `syncTopicConfigs` is responsible for syncing the topic configs. Before that sync happens, topic configurations could be out of sync between the two clusters.

In the worst case, this could lead to data loss eg. when we have a compacted topic being mirrored between clusters which is incorrectly created with the default configuration of `cleanup.policy = delete` on the destination before the configurations are sync'd via `syncTopicConfigs`.

Here is an example of the divergence:

Source Topic:

```

Topic: foobar PartitionCount: 1 ReplicationFactor: 1 Configs: cleanup.policy=compact,segment.bytes=1073741824

```

Destination Topic:

```

Topic: A.foobar PartitionCount: 1 ReplicationFactor: 1 Configs: segment.bytes=1073741824

```

A safer approach is to ensure that the right configurations are set on the destination cluster before data is replicated to it.

Issue Links

• links to: GitHub Pull Request #10217