For weird historical reasons we have 2.14Tb of data in a GCS bucket that stores docker images for Google Container Registry (GCR).
gcloud container images delete <image> to delete thousands of unused images, however stackdriver says there's been no change in the total bytes stored in the underlying GCS bucket.
It looks like
gcloud container images delete has deleted the image metadata from the registry, but not the underlying layers.
Is there a way we can garbage collect the unused data from GCS and reduce our monthly bill?
Update after accepting an answer
Here's a chart of the total object size in our GCS bucket - it looks like objects are garbage collected about once every 24 hours (around midday UTC in our case)