Pruning of docker-registry in Red Hat OpenShift Container Platform not work as expected

Issue

• We saw an increase of the disk space used by our docker-registry on both platforms (7 days +50%). We found 120 images & tags in the file system, which are no longer in OpenShift (neither ImageStream nor ImageStream Tag). We are not sure yet how to reproduce this. But it seems, that the cleanup only takes place based on the information that are in OpenShift. So if there is no longer a imageStream & tag, it will not be pruned. This has a problem, when the pruner fails > The openshift resources could be deleted, but not the actual files. Thus they stay there forever.