// Module included in the following assemblies:
//
// assembly-using-the-topic-operator.adoc

[id='proc-configuring-kafka-topic-{context}']
= Configuring a Kafka topic

Use the properties of the `KafkaTopic` resource to configure a Kafka topic.

You can use `kubectl apply` to create or modify topics, and `kubectl delete` to delete existing topics.

For example:

* `kubectl apply -f <topic-config-file>`
* `kubectl delete KafkaTopic <topic-name>`

This procedure shows how to create a topic with 10 partitions and 2 replicas.

.Before you start

It is important that you consider the following before making your changes:

* Kafka does _not_ support making the following changes through the `KafkaTopic` resource:
** Changing topic names using `spec.topicName`
** Decreasing partition size using `spec.partitions`
* You cannot use `spec.replicas` to change the number of replicas that were initially specified.
* Increasing `spec.partitions` for topics with keys will change how records are partitioned, which can be particularly problematic when the topic uses _semantic partitioning_.

.Prerequisites

* A running Kafka cluster xref:con-securing-kafka-authentication-{context}[configured with a Kafka broker listener using TLS authentication and encryption].
* A running Topic Operator (typically xref:assembly-kafka-entity-operator-deployment-configuration-kafka[deployed with the Entity Operator]).
* For deleting a topic, `delete.topic.enable=true` (default) in the `spec.kafka.config` of the `Kafka` resource.

.Procedure

. Prepare a file containing the `KafkaTopic` to be created.
+
.An example `KafkaTopic`
[source,yaml,subs="attributes+"]
----
apiVersion: {KafkaTopicApiVersion}
kind: KafkaTopic
metadata:
  name: orders
  labels:
    strimzi.io/cluster: my-cluster
spec:
  partitions: 10
  replicas: 2
----
+
TIP: When modifying a topic, you can get the current version of the resource using `kubectl get kafkatopic orders -o yaml`.

. Create the `KafkaTopic` resource in Kubernetes.
+
[source,shell,subs=+quotes]
kubectl apply -f _TOPIC-CONFIG-FILE_
