How to deploy Charmed Kafka

To deploy a Charmed Kafka cluster on a bare environment, it is necessary to:

1. Set up a Juju Controller
2. Set up a Juju Model
3. Deploy Charmed Kafka and Charmed ZooKeeper
4. (Optionally) Create an external admin user

In the next subsections, we will cover these steps separately by referring to relevant Juju documentation and providing details on the Charmed Kafka specifics. If you already have a Juju controller and/or a Juju model, you can skip the associated steps.

Juju controller setup

Before deploying Kafka, make sure you have a Juju controller accessible from your local environment using the Juju client snap.

The properties of your current controller can be listed using juju show-controller. Make sure that the controller’s back-end cloud is not K8s. The cloud information can be retrieved with the following command

juju show-controller | yq '.[].details.cloud'

IMPORTANT If the cloud is k8s, please refer to the Charmed Kafka K8s documentation instead.

You can find more information on how to bootstrap and configure a controller for different clouds here. Make sure you bootstrap a machine Juju controller.

Juju model setup

You can create a new Juju model using

juju add-model <model>

Alternatively, you can use a pre-existing Juju model and switch to it by running the following command:

juju switch <model-name>

Make sure that the model is not a k8s type. The type of the model can be obtained by

juju show-model | yq '.[].type'

IMPORTANT If the model is k8s, please refer to the Charmed Kafka K8s documentation instead.

Deploy Charmed Kafka and Charmed ZooKeeper

The Kafka and ZooKeeper charms can both be deployed as follows:

$ juju deploy kafka --channel 3/stable -n <kafka-units> --trust
$ juju deploy zookeeper --channel 3/stable -n <zookeeper-units>

where <kafka-units> and <zookeeper-units> – the number of units to deploy for Kafka and ZooKeeper. We recommend values of at least 3 and 5 respectively.

NOTE The --trust option is needed for the Kafka application if NodePort is used. For more information about the trust options usage, see the Juju documentation.

After this, it is necessary to connect them:

$ juju relate kafka zookeeper

Once all the units show as active|idle in the juju status output, the deployment should be ready to be used.

(Optional) Create an external admin users

Charmed Kafka aims to follow the secure by default paradigm. As a consequence, after being deployed the Kafka cluster won’t expose any external listener. In fact, ports are only opened when client applications are related, also depending on the protocols to be used. Please refer to this table for more information about the available listeners and protocols.

It is however generally useful for most of the use-cases to create a first admin user to be used to manage the Kafka cluster (either internally or externally).

To create an admin user, deploy the Data Integrator Charm with extra-user-roles set to admin

juju deploy data-integrator --channel stable --config topic-name=test-topic --config extra-user-roles=admin

and relate to the Kafka charm

juju relate data-integrator kafka

To retrieve authentication information such as the username, password, etc. use

juju run data-integrator/leader get-credentials