Resize a Dedicated Kafka Cluster in Confluent Cloud

This topic shows you how to resize existing Dedicated Apache Kafka® clusters. Dedicated clusters are provisioned and billed in terms of Confluent Unit for Kafka (CKU). Evaluating the number of CKUs your cluster requires helps you to reduce costs or scale to meet your streaming needs.

When you resize a Dedicated Kafka cluster, Confluent rebalances the cluster to help ensure a balanced load across the remaining brokers in the cluster. If you’re reducing the size of the cluster, Confluent removes unused brokers at the end of the rebalance operation.

Expand a Dedicated Kafka Cluster

This section shows you how to expand an existing Dedicated Kafka cluster. 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.

Prerequisites:

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.

  1. Select your Confluent Cloud cluster.

    Confluent Cluster panel
  2. Click the Cluster Settings, the Capacity tab and on the Adjustable limits pane, select Adjust capacity.

    Confluent Cluster capacity
  3. 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.

    Expand Confluent Cluster capacity
  4. Confirm your changes and click Continue. For details on how to shrink a cluster, see Shrink a Dedicated Kafka Cluster.

    Confirm cluster expansion

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

Shrink a Dedicated Kafka Cluster

This section shows you how to shrink an existing Dedicated Kafka cluster. You can reduce the capacity of a cluster one CKU at a time. Multi-zone Dedicated clusters require a minimum capacity of 2 CKUs. For more information, see CKU limits per cluster.

Prerequisites:

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

  1. Select your Confluent Cloud cluster.

    Confluent Cluster panel
  2. Click the Cluster Settings, the Capacity tab and on the Adjustable limits pane, select Adjust capacity.

    Confluent Cluster capacity
  3. View the current usage on your cluster and determine if your cluster load is low enough to support a shrink operation. In general, shrinking a highly loaded cluster will result in application performance issues. For more information, see Cluster Load Metric for Dedicated Clusters in Confluent Cloud, and Kafka Cluster.

  4. Use the slider to reduce the number of CKUs for the cluster. You can reduce the capacity 1 CKU at a time.

    You will see a preview of the reduced capacity before it is applied. If you are satisfied with the changes, click Apply changes. For details on how to expand a cluster, see Expand a Dedicated Kafka Cluster.

    Expand Confluent Cluster capacity

    Note

    In rare scenarios, such as when you have just expanded your cluster, you might see the following warning in the Cloud Console. If this occurs, wait 1-2 hours and retry the shrink operation.

    ../_images/ccloud-shrink-metrics-delayed.png
  5. Confirm your changes and click Continue.

    Confirm cluster expansion

Important

If the shrink operation fails, the cluster will expand to its original capacity, and you will be notified when the expansion operation is complete.

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