Static docker manifests should not be considered as expired resource

Artifactory has a mechanism to re-fetch stale resources on demand once these are expired (i.e. docker manifest with a 'latest' tag which is a dynamic tag, or index file that includes versions in it or an other dynamic data that might get updated in the proxied server after it was cached in Artifactory). The resource expiry is based on the remote repository Retrieval Cache Period configuration.
Unlike dynamic manifests such the latest tag and docker manifest lists, static manifest tags should never get 'expired' and Artifactory should not query the proxied server to check if the file was updated.

To control the list of dynamic tags that are considered as expirable and add additional tags but latest, there is a system property that can be added to the artifactory.system.properties file. For example, to ensure that latest, tag-x, tag-y will be expirable, the following property can be added:
artifactory.docker.expired.tags=latest,tag-x,tag-y