Deleting Broker Data Volumes

Delete broker data volumes to remove persistent MQTT data.

Deleting broker data volumes permanently removes all persistent MQTT data, including client sessions, retained messages, and subscriptions. This operation is typically performed when you need to completely reset the broker state or decommission a broker cluster.

This operation is destructive and cannot be undone. Ensure you have backups if you need to preserve any data.

Kubernetes

Deleting Broker Data Volumes on Kubernetes

Prerequisites

• kubectl access to the installation with the current context namespace set to the target namespace.

• The broker cluster must be scaled down to zero replicas before deleting volumes.

• Note the number of replicas that were running before scaling down, as you'll need this to scale back up.

Procedure

1. Identify all broker data volumes. The number of PersistentVolumeClaims (PVCs) depends on the number of broker replicas that were previously running.

To list all broker data and log volumes, run:

kubectl get pvc -lapp=broker -n ${NAMESPACE}

Example output

NAME                  STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   VOLUMEATTRIBUTESCLASS   AGE
brokerdata-broker-0   Bound    pvc-3e4cbb94-0e59-4e93-b90b-3fa120ac4d23   1Gi        RWO            efs-sc         <unset>                 11m
brokerdata-broker-1   Bound    pvc-1316bdc4-5e27-4319-8a15-69e6e8262e12   1Gi        RWO            efs-sc         <unset>                 8m32s
brokerdata-broker-2   Bound    pvc-6cdbcb83-e7ad-4381-b3ad-bb31484ae7d0   1Gi        RWO            efs-sc         <unset>                 7m58s
brokerlog-broker-0    Bound    pvc-5f7704ab-c64f-4f0c-b611-1d6ccf476ada   200Mi      RWO            efs-sc         <unset>                 11m
brokerlog-broker-1    Bound    pvc-52a2c747-7c20-485b-86e9-60cad9e21a45   200Mi      RWO            efs-sc         <unset>                 8m32s
brokerlog-broker-2    Bound    pvc-467f2e1f-9e64-4981-9c19-cee42b00dfb5   200Mi      RWO            efs-sc         <unset>                 7m58s

1. Note down the number of replicas that were running before scaling down. In the example above, there are 3 replicas (broker-0, broker-1, broker-2).

2. Delete broker data volumes:

kubectl delete pvc -n ${NAMESPACE} ${PVC_NAME}

Example

For each PVC that starts with brokerdata, run:

kubectl delete pvc -n ${NAMESPACE} brokerdata-broker-0

Repeat this command for each brokerdata-* volume you identified in step 1.

Alternative: Automated deletion

To delete all broker data volumes at once, use the following command:

kubectl get pvc -lapp=broker -n ${NAMESPACE} -o name | grep brokerdata | xargs kubectl delete -n ${NAMESPACE}

This automated approach deletes only the brokerdata-* volumes.

1. After deleting the data volumes, scale the StatefulSet back to the original number of replicas. Replace ${NUM_REPLICAS} with the number that you noted before scaling down:

kubectl scale sts broker -n ${NAMESPACE} --replicas ${NUM_REPLICAS}

The broker pods will restart with fresh, empty data volumes.

Docker Compose

Deleting Broker Data Volumes on Docker Compose

1. The broker container must be stopped before deleting the volume. If the Connectware is running, go to the Connectware installation directory (default: /opt/connectware) and run:

docker compose down

1. List all Docker volumes to identify the broker data volume:

docker volume ls

1. Locate the broker data volume in the list. It typically has a name like <connectware_installation>_brokerData.

2. Delete the broker data volume:

docker volume rm <connectware_brokerData>

Replace <connectware_brokerData> with the actual volume name from step 2.

1. Start Connectware again to recreate the broker data volume:

docker compose up -d

The broker will create a fresh, empty data volume when it restarts.