RegistryUI settings can only be managed by an administrator.
The Registry > Settings page is used to configure RegistryUI.
The Garbage Collection tab is used to perform garbage collection using the Docker Registry. For more information about registry garbage collection see https://docs.docker.com/registry/garbage-collection/. RegistryUI uses the official Docker Registry image and uses the standard method to perform garbage collection documented at https://docs.docker.com/registry/garbage-collection/.
The "Daily At" field is used to define the time at which garbage collection is automatically performed every day. The field can be left empty to disable automatic garbage collection.
The "Perform Garbage Collection" button can be used to immediately perform garbage collection. Garbage collection is performed in the background and may take a significant amount of time, depending on the registry size (number tags and deleted blobs).
While garbage collection is performed, the Docker Registry is automatically taken offline and is brought back online when garbage collection has completed. While the registry is offline, users cannot push/pull images or log into the Docker Registry. The RegistryUI website is still available, but certain functionality is limited while the registry is offline. The RegistryUI Extended API and the Docker Registry API are both unavailable while the registry is offline. Users accessing the registry in any way are notified that the registry is offline.
Garbage collection could also be triggered using a cron job, by using the RegistryUI Extended API.
Using a simple curl command, garbage collection can be invoked outside of RegistryUI.
curl -u username:usertoken -d "" https://registry.yoursite.com/udr/v1api/garbagecollection
For more information see /udr/v1api/garbagecollection.