The service account used to run the registry instances requires additional permissions in order to list some resources. 

a. Get the service account name: 

$ service_account=$(oc get -n openshift-image-registry \ -o jsonpath='{.spec.template.spec.serviceAccountName}' deploy/image-registry) 

b. Add the system:image-pruner  cluster role to the service account: 

5. Optional: Run the pruner in dry-run mode. 

$ oc adm policy add-cluster-role-to-user \ system:image-pruner -z \ ${service_account} -n openshift-image-registry 

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 '/usr/bin/dockerregistry -prune=check' 

Alternatively, to get the exact paths for the prune candidates, increase the logging level: 

$ 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 

