Chapter 3. Technology Previews
Technology Preview features are not supported with Red Hat production service-level agreements (SLAs) and might not be functionally complete; therefore, Red Hat does not recommend implementing any Technology Preview features in production environments. This Technology Preview feature provides early access to upcoming product innovations, enabling you to test functionality and provide feedback during the development process. For more information about support scope, see Technology Preview Features Support Scope.
3.1. Cruise Control for cluster rebalancing
Cruise Control remains in Technology Preview, with some new enhancements.
You can install Cruise Control and use it to rebalance your Kafka cluster using optimization goals — defined constraints on CPU, disk, network load, and more. In a balanced Kafka cluster, the workload is more evenly distributed across the broker pods.
Cruise Control helps to reduce the time and effort involved in running an efficient and balanced Kafka cluster.
A zipped distribution of Cruise Control is available for download from the Customer Portal. To install Cruise Control, you configure each Kafka broker to use the provided Metrics Reporter. Then, you set Cruise Control properties, including optimization goals, and start Cruise Control using the provided script.
The Cruise Control server is hosted on a single machine for the whole Kafka cluster.
When Cruise Control is running, you can use the REST API to:
- Generate dry run optimization proposals from multiple optimization goals
- Initiate an optimization proposal to rebalance the Kafka cluster
Other Cruise Control features are not currently supported, including anomaly detection, notifications, write-your-own goals, and changing the topic replication factor.
See Cruise Control for cluster rebalancing.
3.1.1. Enhancements to the Technology Preview
The following enhancements have been added to the Technology Preview of Cruise Control for cluster rebalancing.
New goal: Minimum topic leaders per broker
You can use a new goal named MinTopicLeadersPerBrokerGoal.
For each topic in a defined group of topics, the goal ensures that each active broker has at least a certain number of leader replicas.
MinTopicLeadersPerBrokerGoal is a default goal and is preset as a hard goal.
See Optimization goals overview
Logging enhancement: Log4j 2
Log4j 2 is now used for Cruise Control logging.
You must update existing configurations for Cruise Control logging (in /opt/cruise-control/config/log4j.properties) from Log4j to Log4j 2 compatible syntax.
