Chapter 6. Developer Previews Developer preview features included with AMQ Streams 2.5. As a Kafka cluster administrator, you can toggle a subset of features on and off using feature gates in the Cluster Operator deployment configuration. The feature gates available as developer previews are at an alpha level of maturity and disabled by default. Important Developer 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 Developer Preview features in production environments. This Developer 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 the support scope, see Developer Preview Support Scope . 6.1. KafkaNodePools feature gate To use KafkaNodePool resources to manage the configuration of pools of Kafka nodes, try the KafkaNodePools feature gate. For more information, see Section 3.5, "(Preview) Node pools for managing nodes in a Kafka cluster" . 6.2. UnidirectionalTopicOperator feature gate To set up the Topic Operator so that it only manages Kafka topics associated with KafkaTopic resources, try the UnidirectionalTopicOperator feature gate. For more information, see Section 3.6, "(Preview) Unidirectional topic management using the Topic Operator" . 6.3. StableConnectIdentities feature gate To use StrimziPodSet resources to manage Kafka Connect and Kafka MirrorMaker 2 pods, try the StableConnectIdentities feature gate. The StableConnectIdentities feature gate controls the use of StrimziPodSet resources to manage Kafka Connect and Kafka MirrorMaker 2 pods instead of using OpenShift Deployment resources. This helps to minimize the number of rebalances of connector tasks. To enable the StableConnectIdentities feature gate, specify +StableConnectIdentities as a value for the STRIMZI_FEATURE_GATES environment variable in the Cluster Operator configuration. Enabling the StableConnectIdentities feature gate env: - name: STRIMZI_FEATURE_GATES value: +StableConnectIdentities See StableConnectIdentities feature gate . 6.4. UseKRaft feature gate Apache Kafka is in the process of phasing out the need for ZooKeeper. With the new UseKRaft feature gate enabled, you can try deploying a Kafka cluster in KRaft (Kafka Raft metadata) mode without ZooKeeper. Caution This feature gate is experimental, intended only for development and testing, and must not be enabled for a production environment. To use KRaft mode, you must also use KafkaNodePool resources to manage the configuration of groups of nodes. To enable the UseKRaft feature gate, specify +UseKRaft,+KafkaNodePools as values for the STRIMZI_FEATURE_GATES environment variable in the Cluster Operator configuration. Enabling the UseKRaft feature gate env: - name: STRIMZI_FEATURE_GATES value: +UseKRaft,+KafkaNodePools Currently, the KRaft mode in AMQ Streams has the following major limitations: Moving from Kafka clusters with ZooKeeper to KRaft clusters or the other way around is not supported. Controller-only nodes cannot undergo rolling updates or be updated individually. Upgrades and downgrades of Apache Kafka versions or the Strimzi operator are not supported. Users might need to delete the cluster, upgrade the operator and deploy a new Kafka cluster. Only the Unidirectional Topic Operator is supported in KRaft mode. You can enable it using the UnidirectionalTopicOperator feature gate. The Bidirectional Topic Operator is not supported and when the UnidirectionalTopicOperator feature gate is not enabled, the spec.entityOperator.topicOperator property must be removed from the Kafka custom resource. JBOD storage is not supported. The type: jbod storage can be used, but the JBOD array can contain only one disk. See the following: UseKRaft feature gate Feature gate releases

Commands:
env: - name: STRIMZI_FEATURE_GATES value: +StableConnectIdentities
env: - name: STRIMZI_FEATURE_GATES value: +UseKRaft,+KafkaNodePools