Chapter 3. Technology Previews

The KafkaNodePools feature gate and the new KafkaNodePool custom resource enables the configuration of different pools of Apache Kafka nodes. This feature gate is at an alpha level of maturity, which means that it is disabled by default, and should be treated as a technology preview.

A node pool refers to a distinct group of Kafka nodes within a Kafka cluster. The KafkaNodePool custom resource represents the configuration for nodes only in the node pool. Each pool has its own unique configuration, which includes mandatory settings such as the number of replicas, storage configuration, and a list of assigned roles. As you can assign roles to the nodes in a node pool, you can try the feature with a Kafka cluster that uses ZooKeeper for cluster management or KRaft mode.

To enable the KafkaNodePools feature gate, specify +KafkaNodePools in the STRIMZI_FEATURE_GATES environment variable in the Cluster Operator configuration.

env:
  - name: STRIMZI_FEATURE_GATES
    value: +KafkaNodePools

env:
  - name: STRIMZI_FEATURE_GATES
    value: +KafkaNodePools

See Configuring node pools.

The UnidirectionalTopicOperator feature gate introduces a unidirectional topic management mode. With unidirectional mode, you create Kafka topics using the KafkaTopic resource, which are then managed by the Topic Operator. This feature gate is at an alpha level of maturity, and should be treated as a technology preview.

To enable the UnidirectionalTopicOperator feature gate, specify +UnidirectionalTopicOperator in the STRIMZI_FEATURE_GATES environment variable in the Cluster Operator configuration.

env:
  - name: STRIMZI_FEATURE_GATES
    value: +UnidirectionalTopicOperator

env:
  - name: STRIMZI_FEATURE_GATES
    value: +UnidirectionalTopicOperator

Up to this release, the only way to use the Topic Operator to manage topics was in bidirectional mode, which is compatible with using ZooKeeper for cluster management. Unidirectional mode does not require ZooKeeper for cluster management, which is an important development as Kafka moves to using KRaft mode for managing clusters.

See Using the Topic Operator.

Use the technology preview of the Kafka Static Quota plugin to set throughput and storage limits on brokers in your Kafka cluster. You enable the plugin and set limits by configuring the Kafka resource. You can set a byte-rate threshold and storage quotas to put limits on the clients interacting with your brokers.

apiVersion: kafka.strimzi.io/v1beta2
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    # ...
    config:
      client.quota.callback.class: io.strimzi.kafka.quotas.StaticQuotaCallback
      client.quota.callback.static.produce: 1000000
      client.quota.callback.static.fetch: 1000000
      client.quota.callback.static.storage.soft: 400000000000
      client.quota.callback.static.storage.hard: 500000000000
      client.quota.callback.static.storage.check-interval: 5

apiVersion: kafka.strimzi.io/v1beta2
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    # ...
    config:
      client.quota.callback.class: io.strimzi.kafka.quotas.StaticQuotaCallback
      client.quota.callback.static.produce: 1000000
      client.quota.callback.static.fetch: 1000000
      client.quota.callback.static.storage.soft: 400000000000
      client.quota.callback.static.storage.hard: 500000000000
      client.quota.callback.static.storage.check-interval: 5

See Setting limits on brokers using the Kafka Static Quota plugin.