Page History

...

The cluster needs to be upgraded before configuring multiple entries in log.dirs. As the upgraded brokers come up, the existing meta.properties  files in each broker are updated with a generated directory.id  and directory.ids . After the upgrade, the metadata.version  is feature  feature flag needs to be upgraded using kafka-features.sh. Then the brokers can be reconfigured with multiple entries in log.dirs.

...

• As per KIP-866, a separate Controller quorum is setup first, and only then the existing brokers are reconfigured and upgraded.
• During the migration, the active controller is still monitoring ZooKeeper relies for log directory failure notifications and still using full LeaderAndIsr requests to process log directory failures for any brokers still running in ZK mode
• The brokers restarting into KRaft mode for the first time update meta.properties to generate and include directory.id  and directory.ids .
• During the migration, the active controller accepts broker registration requests from brokers restarting into KRaft mode, indicating multiple online log directories, but keeps brokers fenced until it learns of all partition to log directory assignments in that broker via the new AssignReplicasToDirs RPC.
• During the migration, replicas are assumed and assigned to log directory Uuid.ZERO until the actual log directory is learnt by the active controller from a broker running in KRaft mode.

...