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val bootstrapServerOpt = parser.accepts("bootstrap-server", "REQUIRED: The Kafka servers to connect to, separated by commas, for instance "localhost:9091,localhost:9092". In case of providing this, a direct Zookeeper connection won't be required.")
                      .withRequiredArg
                      .describedAs("server to connect to")
                      .ofType(classOf[String])
val commandConfigOpt = parser.accepts("command-config", "Property file containing configs to be passed to Admin Client. " +
                      "This is used only with --bootstrap-server option for describing and altering broker configs.")
                      .withRequiredArg
                      .describedAs("command config property file")
                      .ofType(classOf[String])

Protocol Changes

The kafka-topics.sh is also capable of altering the partition number, we need to add a protocol to implement this behavior. The simplest protocol we can give is where the request contains a list of topics with associated partition numbers and as a response we get the list of topics with the associated errors (or errors nulled out if it was successful).

AlterTopics Request (version: 0) => validate_only [topic_partition_change]
  validate_only => BOOLEAN
  topic_partition_change => topic_name partition_number
    topic_name => STRING
    partition_number => INT32


AlterTopics Response (version: 0) => throttle_time_ms [topic_partition_result]
  throttle_time_ms => INT32
  topic_partition_result => topic_name error_code error_message
    topic_name => STRING
    error_code => INT16
    error_message => NULLABLE_STRING

Authorization implications:

• From the authorization perspective using this protocol would require an ALTER operation on a Topic resource. Both currently available and therefore can be used.

Proposed Changes

The change proposed in this KIP is to add an extra option as stated above and to migrate create, delete, list and describe operations to use a broker connection. This would be a backward compatible change, meaning the zookeeper way would be still available until a further point in time but hopefully would deprecate it as part of this KIP.

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Compatibility, Deprecation, And Migration Plan

This KIP won't implement topic config alternation as that is deprecated in the TopicCommand and should be done by kafka-configs.sh. The only alternation we allow is changing the partition number for topics.

No other existing behavior would be removed and the implementation would be done in a backward compatible way.

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