Make Zookeeper usage optional for KafkaContainer

Hi

Starting since Kafka 2.8 Zookeeper is now an optional component because Kafka node can act as an active controller (new “process.roles” property). However I see from the code (configure method in the KafkaContainer class), that zookeeper.connect property is always added via environment variables:

if (externalZookeeperConnect != null) {
            withEnv("KAFKA_ZOOKEEPER_CONNECT", externalZookeeperConnect);
        } else {
            addExposedPort(ZOOKEEPER_PORT);
            withEnv("KAFKA_ZOOKEEPER_CONNECT", "localhost:" + ZOOKEEPER_PORT);
            command += "echo 'clientPort=" + ZOOKEEPER_PORT + "' > zookeeper.properties\n";
            command += "echo 'dataDir=/var/lib/zookeeper/data' >> zookeeper.properties\n";
            command += "echo 'dataLogDir=/var/lib/zookeeper/log' >> zookeeper.properties\n";
            command += "zookeeper-server-start zookeeper.properties &\n";
}

And by default Zookeeper is always started (externalZookeeperConnect is not initialized). Also there’s no API to distinguish between two modes (with and without Zookeeper) which I guess will be useful for the developers.

[danielpetisme]

Hi,

A made a Kraft POC. https://github.com/testcontainers/testcontainers-java/pull/6129

Feedbacks are welcome!

[pkeugine]

thanks for the update @kiview, @ecsimsw and I read the comments as well. We’ll focus on this issue from now on.