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00000000000000000000-0000000000.checkpoint

This checkpoint file is also created by the kafka-storage tool in the __cluster-metadata-0  directory. Now, it will also contain the data that used to be contained in the bootstrap.checkpoint file. It is important to note that the bootstrap records must be less than 8MB of total size if transactions are not supported, since that is the maximum batch size in bytes supported by KRaft.

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Both the Kafka broker and controller nodes will delete the bootstrap.checkpoint file from the metadata log dir if the node has been asked to load a snapshot that contains at least one metadata record.

Kafka Storage Format Command

The kafka-storage format command is responsible for creating the zero checkpoint (00000000000000000000-0000000000.checkpoint). The metadata that is currently written to the bootstrap.checkpoint will instead be written to the zero checkpoint.

Formatting will fail if the metadata log directory already contains the bootstrap.checkpoint or the zero checkpoint. Formatting will be skip if the metadata log dir already contains the bootstrap.checkpoint or the zero checkpoint, and the --ignore-formatted flag is provided.

Compatibility, Deprecation, and Migration Plan

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