Since you may wish to have access to your data after spinning down your cluster, Cortex's bucket, stackdriver logs, and Prometheus volume are not automatically deleted when running cortex cluster-gcp down.

cortex cluster-gcp down

The cortex cluster-gcp down command doesn't wait for the cluster to spin down. You can ensure that the cluster has spun down by checking the GKE console.

Delete Volumes

The volumes used by Cortex's Prometheus and Grafana instances are not deleted by default, as they might contain important information. If these volumes are not required anymore, you can delete them in the GCP console. Navigate to the Disks page (be sure to set the appropriate project), select the volumes, and click "Delete". The Prometheus and Grafana volumes that Cortex created have a name that starts with gke-<cluster name>-, and the kubernetes.io/created-for/pvc/name tag starts with prometheus- and grafana- respectively.