Chapter 4. Deprecated features

Support for Java 8 was deprecated in Kafka 3.0.0 and AMQ Streams 2.0. Java 8 will be unsupported for all AMQ Streams components, including clients, in the future.

AMQ Streams supports Java 11. Use Java 11 when developing new applications. Plan to migrate any applications that currently use Java 8 to Java 11.

Two environment variables were removed from the standalone User Operator configuration:

Previously, these environment variables were set in install/user-operator/05-Deployment-strimzi-user-operator.yaml, which is used for deploying the standalone User Operator only.

The User Operator zookeeperSessionTimeoutSeconds property is no longer required and is now deprecated. This property was set in the userOperator property in the Kafka resource.

Kafka MirrorMaker replicates data between two or more active Kafka clusters, within or across data centers. Kafka MirrorMaker 1 is deprecated for Kafka 3.0.0 and will be removed in Kafka 4.0.0. MirrorMaker 2.0 will be the only version available. MirrorMaker 2.0 is based on the Kafka Connect framework, connectors managing the transfer of data between clusters.

As a consequence, the AMQ Streams KafkaMirrorMaker custom resource which is used to deploy Kafka MirrorMaker 1 has been deprecated. The KafkaMirrorMaker resource will be removed from AMQ Streams when Kafka 4.0.0 is adopted.

If you are using MirrorMaker 1 (referred to as just MirrorMaker in the AMQ Streams documentation), use the KafkaMirrorMaker2 custom resource with the IdentityReplicationPolicy. MirrorMaker 2.0 renames topics replicated to a target cluster. IdentityReplicationPolicy configuration overrides the automatic renaming. Use it to produce the same active/passive unidirectional replication as MirrorMaker 1.

See Kafka MirrorMaker 2.0 cluster configuration

The OpenShift templates provided with the AMQ Streams example files have been removed and are no longer supported. The template configuration files were provided to deploy Kafka components from the OpenShift console. For example, templates were included for deploying Kafka with ephemeral or persistent storage. The templates offered some benefit when using OpenShift 3.11. Since OpenShift 4.x, it is easier to use the Cluster Operator to install and manage Kafka components in the OpenShift console.

With the introduction of build configuration to the KafkaConnect resource, AMQ Streams can now automatically build a container image with the connector plugins you require for your data connections.

As a result, support for Kafka Connect with Source-to-Image (S2I) was removed.

You can migrate Kafka Connect S2I instances to Kafka Connect instances.

See Migrating from Kafka Connect with S2I to Kafka Connect