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Compatibility, Deprecation, and Migration Plan

Shared interface for plugable consensus and metadata storage systems should be compatible for Zookeeper-based implementation. Also this implementation will likely be the default one.

As part of this KIP it will be required to rework some system and replication tools. It will not be possible anymore to rely on Zookeeper as a default metadata storage system, it will also not be possible to use it to trigger particular administrative commands. Most of the tools are related to topic management (create topics, reassign partitions etc) and consumer group management (offset checker etc).

The approach to topic tools is covered in KIP-4 - we will move all administrative logic to brokers. KIP-4 is currently under development and has agreed Wire Protocol changes.

The consumer group tools should be covered separately. Having New Java Consumer in 0.9 release with server-side coordinator may let us deprecate old consumer and thus all tools related with it. Consumer group tools should work as usual if brokers are run with Zookeeper based implementation of the shared interfaceThe use of zookeeper.connect in server.properties will still be honored. In the code we should have the default value of the new configuration.

Rejected Alternatives

If there are alternative ways of accomplishing the same thing, what were they? The purpose of this section is to motivate why the design is the way it is and not some other way.

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