CHAPTER 8. PRUNING OBJECTS TO RECLAIM RESOURCES The service account used to run the registry instances requires additional permissions in order to list some resources. a. Get the service account name: b. Add the  system:image-pruner  cluster role to the service account: 5.  Optional: Run the pruner in dry-run mode. $ service_account=$(oc get -n openshift-image-registry \ -o jsonpath='{.spec.template.spec.serviceAccountName}' deploy/image-registry) $ oc adm policy add-cluster-role-to-user \ system:image-pruner -z \ ${service_account} -n openshift-image-registry $ oc -n openshift-image-registry exec pod/image-registry-3-vhndw -- /bin/sh -c  '/usr/bin/dockerregistry -prune=check' Alternatively, to get the exact paths for the prune candidates, increase the logging level: To see how many blobs would be removed, run the hard pruner in dry-run mode. No changes are actually made. The following example references an image registry pod called  image- registry-3-vhndw : $ oc -n openshift-image-registry exec pod/image-registry-3-vhndw -- /bin/sh -c  'REGISTRY_LOG_LEVEL=info /usr/bin/dockerregistry -prune=check' Example output time="2017-06-22T11:50:25.066156047Z" level=info msg="start prune (dry-run mode)"  distribution_version="v2.4.1+unknown" kubernetes_version=v1.6.1+$Format:%h$  openshift_version=unknown time="2017-06-22T11:50:25.092257421Z" level=info msg="Would delete blob:  sha256:00043a2a5e384f6b59ab17e2c3d3a3d0a7de01b2cabeb606243e468acc663fa5"  go.version=go1.7.5 instance.id=b097121c-a864-4e0c-ad6c-cc25f8fdf5a6 time="2017-06-22T11:50:25.092395621Z" level=info msg="Would delete blob:  sha256:0022d49612807cb348cabc562c072ef34d756adfe0100a61952cbcb87ee6578a"  go.version=go1.7.5 instance.id=b097121c-a864-4e0c-ad6c-cc25f8fdf5a6 time="2017-06-22T11:50:25.092492183Z" level=info msg="Would delete blob:  sha256:0029dd4228961086707e53b881e25eba0564fa80033fbbb2e27847a28d16a37c"  go.version=go1.7.5 instance.id=b097121c-a864-4e0c-ad6c-cc25f8fdf5a6 time="2017-06-22T11:50:26.673946639Z" level=info msg="Would delete blob:  sha256:ff7664dfc213d6cc60fd5c5f5bb00a7bf4a687e18e1df12d349a1d07b2cf7663"  go.version=go1.7.5 instance.id=b097121c-a864-4e0c-ad6c-cc25f8fdf5a6 time="2017-06-22T11:50:26.674024531Z" level=info msg="Would delete blob:  sha256:ff7a933178ccd931f4b5f40f9f19a65be5eeeec207e4fad2a5bafd28afbef57e"  go.version=go1.7.5 instance.id=b097121c-a864-4e0c-ad6c-cc25f8fdf5a6 time="2017-06-22T11:50:26.674675469Z" level=info msg="Would delete blob:  sha256:ff9b8956794b426cc80bb49a604a0b24a1553aae96b930c6919a6675db3d5e06"  go.version=go1.7.5 instance.id=b097121c-a864-4e0c-ad6c-cc25f8fdf5a6 ... Would delete 13374 blobs Would free up 2.835 GiB of disk space Use -prune=delete to actually delete the data 121