Configuration Options for the rebalancer tool

The following configuration options are specific to the rebalancer tool. For any configuration options related to metrics reporting, see Confluent Metrics Reporter configuration.

The configuraton file path is passed using the --config-file option. There are no required configurations to test the tool, although confluent.rebalancer.license is required after 30 days. The following configurations are supported.

confluent.license or confluent.rebalancer.license

Confluent will issue a license key to each subscriber. The license key will be a short snippet of text that you can copy and paste. Without the license key, you can use the Confluent Rebalancer for a 30-day trial period. If you are a subscriber and don’t have a license key, contact Confluent Support at

  • Type: string
  • Valid Values: Confluent Platform license
  • Importance: high

The maximum amount of time the rebalancer will collect metrics for. If the collection does not succeed before the timeout elapses, then the rebalance command will fail.

  • Type: int
  • Default: 60000
  • Importance: low

The topic in which the metrics reporter publishes its metrics.

  • Type: string
  • Default: “_confluent-metrics”
  • Importance: low

The log.dir volume will have at least the specified percentage of free space during and after the rebalance. For example, if the total volume space is 100 GB and this configuration is defined as 20, then the rebalancer will use up to 80 GB during the rebalance. This is supported in Confluent 3.2 only (for both rebalancer and brokers), and only if every broker in the cluster has a single log.dir. In versions where this attribute supported, it is enabled by default; otherwise, it is disabled.

  • Type: double
  • Default: 20.0
  • Valid Values: [0,…,100]
  • Importance: low

You can configure the consumer used to retrieve metrics data by prefixing the consumer configuration name with confluent.rebalancer.metrics.. For example, to configure the consumer to use SASL_SSL, specify the following:
confluent.rebalancer.metrics.sasl.mechanism=GSSAPI required \
        useKeyTab=true \
        storeKey=true \
        keyTab="/path/to/kerberos/kafka.user.keytab" principal="kafka@KAFKA.SECURE";