Configure topics

Hazelcast provides a distribution mechanism for publishing messages that are delivered to multiple subscribers. This is known as a publish/subscribe (pub/sub) messaging model. Publishing and subscription operations are cluster wide. When a member subscribes to a topic, it is registered to receive messages published by any member in the cluster, including any new members that joined after you added the listener. You can create and configure topics using the Topic custom resource.

Configure a topic resource

You can use any of the following configuration options in the Topic resource. For more information, see the API reference.

Field	Description
name	Name of the topic that you're creating. If empty, the custom resource (CR) name is used.
hazelcastResourceName	The name of the Hazelcast resource.
globalOrderingEnabled	When true, all nodes listening to the same topic get their messages in the same order.
multiThreadingEnabled	When true, enables multi-threaded processing of incoming messages. Otherwise, a single thread handles all topic messages. note You cannot enable multi-threading when global ordering is in use.

Example configuration

The following Topic custom resource creates a topic configuration for the Hazelcast custom resource that is defined in the hazelcastResourceName field.

Example configuration

yaml

apiVersion: hazelcast.com/v1alpha1
kind: Topic
metadata:
  name: topic-sample
spec:
  hazelcastResourceName: hazelcast-sample
  globalOrderingEnabled: true
  multiThreadingEnabled: false

After creating the Topic resource, you can check its status:

shell

kubectl get topic topic-sample -o wide

NAME           STATUS    HAZELCAST-RESOURCE   MESSAGE
topic-sample   Success   hazelcast-sample