Status

Current state: Voting In Progress (vote thread)Accepted

Discussion thread: here

Voting Discussion thread: here

JIRA: KAFKA-5061

Released: 2.3.0

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

...

The change will affect any existing cluster where client.id has not been over-ridden in the worker configuration. Since the current default is not useful for JMX monitoring the change should have minimal impact. 

Any client IDs specified in the worker configuration via producer.client.id or consumer.client.id properties will remain unchanged, as those will take precedence.

While this change will not affect quota limits, in some cases it could have an indirect impact on resource usage by a Connector. For example, a system that was enforcing quotas using the default "consumer-[id]" client ids will need to update their configuration to enforce quota on "connector-consumer-[task-id]" instead. Note that enforcing quotas on default client ids in this way is not recommended, before or after this change. For systems that were not enforcing any quota limits on client ids, or using default quotas, no change is expected.

Rejected Alternatives

Add a worker configuration option to automatically append task ID to the client ID used by producer or consumer instances instantiated by a Worker. This ensures all JMX MBean names used within a Kafka Connect cluster are distinct.

This approach was rejected because adding new configuration options is considered a larger change to public interfaces than necessary.

Allow overriding client.id on a per-connector basis

This option does not give the required level of granularity, individual tasks would still have name conflicts without other tasks create by the same connector.  This could be avoided if the connector could control the client id at the task level, but that would require a much more complex change.