Chapter 9. Deprecated features

See the Streams for Apache Kafka Custom Resource API Reference.

Support for Java 11 is deprecated from Kafka 3.7.0 and Streams for Apache Kafka 2.7. Java 11 will be unsupported for all Streams for Apache Kafka components, including clients, in release 3.0.

Streams for Apache Kafka supports Java 17. Use Java 17 when developing new applications. Plan to migrate any applications that currently use Java 11 to 17.

If you want to continue using Java 11 for the time being, Streams for Apache Kafka 2.5 provides Long Term Support (LTS). For information on the LTS terms and dates, see the Streams for Apache Kafka LTS Support Policy.

The storage overrides (*.storage.overrides) for configuring per-broker storage are deprecated and will be removed in Streams for Apache Kafka 3.0. If you are using the storage overrides, migrate to KafkaNodePool resources and use multiple node pools with a different storage class each.

For more information, see PersistentClaimStorage schema reference.

You can use configuration providers to load configuration data from external sources for all Kafka components, including producers and consumers.

Previously, you could enable the io.strimzi.kafka.EnvVarConfigProvider environment variable configuration provider using the config.providers properties in the spec configuration of a component. However, this provider is now deprecated and will be removed in Streams for Apache Kafka 3.0. Therefore, it is recommended to update your implementation to use Kafka’s own environment variable configuration provider (org.apache.kafka.common.config.provider.EnvVarConfigProvider) to provide configuration properties as environment variables.

apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaConnect
metadata:
  name: my-connect
  annotations:
    strimzi.io/use-connector-resources: "true"
spec:
  # ...
  config:
    # ...
    config.providers: env
    config.providers.env.class: org.apache.kafka.common.config.provider.EnvVarConfigProvider
  # ...

apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaConnect
metadata:
  name: my-connect
  annotations:
    strimzi.io/use-connector-resources: "true"
spec:
  # ...
  config:
    # ...
    config.providers: env
    config.providers.env.class: org.apache.kafka.common.config.provider.EnvVarConfigProvider
  # ...

Identity replication policy is a feature used with MirrorMaker 2 to override the automatic renaming of remote topics. Instead of prepending the name with the source cluster’s name, the topic retains its original name. This setting is particularly useful for active/passive backups and data migration scenarios.

To implement an identity replication policy, you must specify a replication policy class (replication.policy.class) in the MirrorMaker 2 configuration. Previously, you could specify the io.strimzi.kafka.connect.mirror.IdentityReplicationPolicy class included with the Streams for Apache Kafka mirror-maker-2-extensions component. However, this component is now deprecated and will be removed in Streams for Apache Kafka 3.0. Therefore, it is recommended to update your implementation to use Kafka’s own replication policy class (org.apache.kafka.connect.mirror.IdentityReplicationPolicy).

For more information, see Configuring Kafka MirrorMaker 2.

Kafka MirrorMaker replicates data between two or more active Kafka clusters, within or across data centers. Kafka MirrorMaker 1 was deprecated in Kafka 3.0 and will be removed in Streams for Apache Kafka 3.0, including the KafkaMirrorMaker custom resource, and Kafka 4.0.0. MirrorMaker 2 will be the only version available. MirrorMaker 2 is based on the Kafka Connect framework, connectors managing the transfer of data between clusters. To avoid disruptions, please transition to MirrorMaker 2 before support ends.

If you’re using MirrorMaker 1, you can replicate its functionality in MirrorMaker 2 by using the KafkaMirrorMaker2 custom resource with the IdentityReplicationPolicy class.. By default, MirrorMaker 2 renames topics replicated to a target cluster, but IdentityReplicationPolicy preserves the original topic names, enabling the same active/passive unidirectional replication as MirrorMaker 1.

For more information, see Configuring Kafka MirrorMaker 2.

Support for OpenAPI v2 is now deprecated and will be removed in Streams for Apache Kafka 3.0. OpenAPI v3 is now supported. Plan to move to using OpenAPI v3.

During the transition to using OpenAPI v2, the /openapi endpoint returns the OpenAPI v2 specification using an additional /openapi/v2 endpoint. A new /openapi/v3 endpoint returns the OpenAPI v3 specification.

The following Kafka Bridge span attributes are deprecated with replacements shown where applicable:

Kafka Bridge uses OpenTelemetry for distributed tracing. The changes are inline with changes to OpenTelemetry semantic conventions. The attributes will be removed in a future release of the Kafka Bridge