Expanding an Amazon MSK cluster - Amazon Managed Streaming for Apache Kafka

Expanding an Amazon MSK cluster

Use this Amazon MSK operation when you want to increase the number of brokers in your MSK cluster. To expand a cluster, make sure that it is in the ACTIVE state.


If you want to expand an MSK cluster, make sure to use this Amazon MSK operation . Don't try to add brokers to a cluster without using this operation.

For information about how to rebalance partitions after you add brokers to a cluster, see Reassign partitions.

Expanding a cluster using the AWS Management Console

  1. Open the Amazon MSK console at https://console.aws.amazon.com/msk/.

  2. Choose the MSK cluster whose number of brokers you want to increase.

  3. On the cluster details page, choose the Edit button next to the Cluster-Level Broker Details heading.

  4. Enter the number of brokers that you want the cluster to have per Availability Zone and then choose Save changes.

Expanding a cluster using the AWS CLI

  1. Run the following command, replacing ClusterArn with the Amazon Resource Name (ARN) that you obtained when you created your cluster. If you don't have the ARN for your cluster, you can find it by listing all clusters. For more information, see Listing Amazon MSK clusters.

    Replace Current-Cluster-Version with the current version of the cluster.


    Cluster versions aren't simple integers. To find the current version of the cluster, use the DescribeCluster operation or the describe-cluster AWS CLI command. An example version is KTVPDKIKX0DER.

    The Target-Number-of-Brokers parameter represents the total number of broker nodes that you want the cluster to have when this operation completes successfully. The value you specify for Target-Number-of-Brokers must be a whole number that is greater than the current number of brokers in the cluster. It must also be a multiple of the number of Availability Zones.

    aws kafka update-broker-count --cluster-arn ClusterArn --current-version Current-Cluster-Version --target-number-of-broker-nodes Target-Number-of-Brokers

    The output of this update-broker-count operation looks like the following JSON.

    { "ClusterArn": "arn:aws:kafka:us-east-1:012345678012:cluster/exampleClusterName/abcdefab-1234-abcd-5678-cdef0123ab01-2", "ClusterOperationArn": "arn:aws:kafka:us-east-1:012345678012:cluster-operation/exampleClusterName/abcdefab-1234-abcd-5678-cdef0123ab01-2/0123abcd-abcd-4f7f-1234-9876543210ef" }
  2. To get the result of the update-broker-count operation, run the following command, replacing ClusterOperationArn with the ARN that you obtained in the output of the update-broker-count command.

    aws kafka describe-cluster-operation --cluster-operation-arn ClusterOperationArn

    The output of this describe-cluster-operation command looks like the following JSON example.

    { "ClusterOperationInfo": { "ClientRequestId": "c0b7af47-8591-45b5-9c0c-909a1a2c99ea", "ClusterArn": "arn:aws:kafka:us-east-1:012345678012:cluster/exampleClusterName/abcdefab-1234-abcd-5678-cdef0123ab01-2", "CreationTime": "2019-09-25T23:48:04.794Z", "OperationArn": "arn:aws:kafka:us-east-1:012345678012:cluster-operation/exampleClusterName/abcdefab-1234-abcd-5678-cdef0123ab01-2/0123abcd-abcd-4f7f-1234-9876543210ef", "OperationState": "UPDATE_COMPLETE", "OperationType": "INCREASE_BROKER_COUNT", "SourceClusterInfo": { "NumberOfBrokerNodes": 9 }, "TargetClusterInfo": { "NumberOfBrokerNodes": 12 } } }

    In this output, OperationType is INCREASE_BROKER_COUNT. If OperationState has the value UPDATE_IN_PROGRESS, wait a while, then run the describe-cluster-operation command again.

Expanding a cluster using the API

To increase the number of brokers in a cluster using the API, see UpdateBrokerCount.