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When the controller handles RaftClient.Listener#handleLoadSnapshot if the checkpoint id has an epoch of 0 and a base offset of 0, the controller will consider these records as the bootstrapping records. The controller will rewrite bootstrap records to the log if they haven't been successfully written in the past. If the controller doesn't load a checkpoint at epoch 0 and offset 0, the controller will load the bootstrap.checkpoint and rewrite the bootstrapping record to the cluster metadata partition if they haven't been successfully written in the past.

Node

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.

Compatibility, Deprecation, and Migration Plan

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