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The Kafka node will delete the bootstrap checkpoint if it is not needed. The checkpoint is not needed if the bootstrapping metadata has been committed to the cluster metadata partition. One implementation is for the node to delete the bootstrap checkpoint if it has loaded a non-empty checkpoint from the cluster metadata partition.

Pre-KIP-1170, both brokers and controllers would create this file during formatting. Post-KIP-1170, this file will no longer be written during formatting.

00000000000000000000-0000000000.checkpoint

This checkpoint file is 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.

Pre-KIP-1170, this file was created by KIP-853-enabled controllers who formatted with either --standalone  or --initial-controllers . Post-KIP-1170, this file is created during formatting by controllers. Brokers will not write this file because they cannot write its contents to the metadata log.

RPC

ApiVersionsResponse

There are two fields in the ApiVersionsResponse that are used to describe the finalized feature version of the cluster. There is an existing issue where ApiVersionsResponse reports finalized feature versions even if the state of the cluster metadata partition is not known. Those two fields are documented as follow:

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