Manage configurations with Apache Kafka® CLI tools
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Aiven for Apache Kafka® services are fully manageable and customizable via either :doc:`advanced configuration flags in the Aiven Console <use-zookeeper>` or the :doc:`Aiven CLI </docs/tools/cli>`. To guarantee the service stability, direct Apache ZooKeeper™ access isn't available, but our tooling provides you all the options that you need - whether your Apache Kafka version has Apache ZooKeeper™ in it or not.

Some of the configuration changes don't need ZooKeeper access, and therefore you can use the standard client tools shipped with the Apache Kafka® binaries. The example below shows how to create a topic using one of such tools, the ``kafka-topics.sh``.

Example: Create a topic with retention time to 30 minutes with ``kafka-topics.sh``
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Each topic in Apache Kafka can have a different retention time, defining for the messages' time to live. The Aiven web console and API offer the ability to set the retention time as part of the topic :ref:`creation <avn_cli_service_topic_create>` or :ref:`update <avn-cli-topic-update>`.

The same can be achieved using the ``kafka-topics.sh`` script included in the `Apache Kafka binaries <https://kafka.apache.org/downloads>`_ with the following steps:

1. Download the `Apache Kafka binaries <https://kafka.apache.org/downloads>`_ and unpack the archive
2. Navigate to the ``bin`` folder containing the Apache Kafka client tools commonly used
3. Create a :doc:`Java keystore and truststore <keystore-truststore>` for the Aiven for Apache Kafka service where you want to create a new topic
4. Create a :doc:`client configuration file <kafka-tools-config-file>` pointing at the keystore and truststore created at the previous steps
5. Run the following command to check the connectivity to the Aiven for Apache Kafka service, replacing the ``<KAFKA_SERVICE_URI>`` with the URI of the service available in the `Aiven Console <https://console.aiven.io/>`_.
   
   .. code::

        ./kafka-topics.sh                           \
            --bootstrap-server <KAFKA_SERVICE_URI>  \
            --command-config consumer.properties    \
            --list


   If successful, the above command lists all the available topics

6. Run the following command to create a new topic named ``new-test-topic`` with a retention rate of 30 minutes.
   Use the kafka-topics script for this and set the retention value in milliseconds ``((100 * 60) * 30 = 180000)``.

   .. code::

        ./kafka-topics.sh  \
            --bootstrap-server <KAFKA_SERVICE_URI>  \
            --command-config consumer.properties    \
            --topic new-test-topic                  \
            --create                                \
            --config retention.ms=180000

7. Run the same command as step 5 to check the topic creation. Optionally you could also run the ``kafka-topics.sh`` command with the ``--describe`` flag to check the details of your topic and the retention rate.

.. Note:: 

    It is currently not possible to change the configurations for an existing topic via ``kafka-topics.sh`` as that requires a connection to ZooKeeper.