Expand a Dedicated Kafka Cluster in Confluent Cloud¶

This topic shows you how to expand an existing Dedicated Apache Kafka® cluster. Increasing the number of CKUs for your cluster enables you to seamlessly scale your cluster to meet your streaming needs. To help you decide whether to expand your cluster, see Cluster Load Metric for Dedicated Clusters in Confluent Cloud and Interpret a high cluster load value.

When you scale a Dedicated Kafka cluster, Confluent adds brokers and rebalances the cluster to help ensure a balanced load across the brokers.

Prerequisites:

An existing Dedicated Kafka cluster.
Usage-based billing enabled.

You can expand the number of CKUs in the Confluent Cloud Console. When you expand using the console, you get a preview of the adjusted load of the cluster.

Select your Confluent Cloud cluster.
Click the Cluster Settings, the Capacity tab and on the Adjustable limits pane, select Adjust capacity.
View the current usage on your cluster and determine if you are hitting any usage limits. Use the slider to increase the number of CKUs for the cluster. You will see a preview of the reduced capacity before it is applied. If you are satisfied with the changes, click Apply changes.
Confirm your changes and click Continue. For details on how to shrink a cluster, see Shrink a Dedicated Kafka Cluster in Confluent Cloud.

You can use the Cluster Management APIs to expand the number of CKUs. You use a HTTP PATCH call, specifying the cluster and environment ID in the request URL. The call must include a payload that contains the new number of CKUs. For parameter descriptions and more details, see Update a cluster.

PATCH /cmk/v2/clusters/lkc-00000?environment=env-test1 HTTP/1.1
Host: api.confluent.cloud

{
   "spec": {
         "config": {
               "kind": "Dedicated",
               "cku": 3
         },
         "environment": {
               "id": "env-test1""
         }
   }
}

You can expand the number of CKUs with the kafka cluster update command of the Confluent CLI. Following is an example command that increases the CKUs for the lkc-abc123 cluster. For full details, see confluent kafka cluster update.

confluent kafka cluster update lkc-abc123 --cku 3

See Dedicated cluster provisioning and resizing time for guidance on how long expansion may take and variables that affect that timing.