// Module included in the following assemblies:
//
// assembly-scheduling.adoc

[id='configuring-pod-anti-affinity-in-kafka-components-{context}']
= Configuring pod anti-affinity in Kafka components

.Prerequisites

* A Kubernetes cluster
* A running Cluster Operator

.Procedure

. Edit the `affinity` property in the resource specifying the cluster deployment.
Use labels to specify the pods which should not be scheduled on the same nodes.
The `topologyKey` should be set to `kubernetes.io/hostname` to specify that the selected pods should not be scheduled on nodes with the same hostname.
For example:
+
[source,yaml,subs=attributes+]
----
apiVersion: {KafkaApiVersion}
kind: Kafka
spec:
  kafka:
    # ...
    template:
      pod:
        affinity:
          podAntiAffinity:
            requiredDuringSchedulingIgnoredDuringExecution:
              - labelSelector:
                  matchExpressions:
                    - key: application
                      operator: In
                      values:
                        - postgresql
                        - mongodb
                topologyKey: "kubernetes.io/hostname"
    # ...
  zookeeper:
    # ...
----

. Create or update the resource.
+
This can be done using `kubectl apply`:
[source,shell,subs=+quotes]
kubectl apply -f _KAFKA-CONFIG-FILE_
