How to delete tags and images?

[jchannon]

I recently ran acr purge and it took 6 hours due to a large amount of images that we had built up. I checked the storage space used using az acr show-usage --name myname --resource-group mygroup before the purge and after and it didn't change.

Some research suggests acr purge only removes tags and/or manifests.

Is there a recommended route to take if I want to delete all tags, manifests and images that are older than x days?

[balcsida]

Hey @jchannon,

Could you please share what command did you run?

[jchannon]

@balcsida acr purge --keep 5 --filter '.*:.*' --ago 60d

[balcsida]

Thanks for the answer!

acr purge un-tags old images by default, so the manifest (and the underlying data) is still kept. To remove everything older than n days you need to include the --untagged switch so that any manifest that no longer has a tag is deleted as well:

acr purge \
  --registry <name> \
  --filter "<repo>:<regex>" \
  --ago <duration> \
  --untagged

After the purge finishes you can re-check with az acr show-usage once the service finishes cleaning up the unreferenced blobs

Be careful, as the --untagged filter doesn't respond to the --ago filter. This will delete all the untagged manifests, regardless of the age of it

[jchannon]

So if I add the --untagged that will delete the actual images and free up space?

I don't have to switch to using az acr repository delete --name myregistry --image acr-helloworld:234123 or should I and that will also delete tags and manifests. The only issue using that command would be finding all images within 60 days

[balcsida]

Yes, --untagged should delete all manifest without tags and it should free up the space from the Container Registry as well. This tool practically uses the same API's as Azure CLI, it is just faster. Here is an example screenshot of an ACR storage metrics while running the --purge command:

The only issue using that command would be finding all images within 60 days

acr purge --keep 5 --filter '.*:.*' --ago 60d --untagged

This would do the following:

1. --filter '.*:.*' matches every repository (.* before the colon) and every tag (.* after it), so all tags in the registry are considered.
2. --ago 60d limits the purge to tags last updated more than 60 days ago, while --keep 5 preserves the five most recent tags in each repository even if they’re older than that cutoff.
3. --untagged then deletes any manifests left without tags, ensuring dangling image data is removed. It does this regardless of the time set in the --ago option, so I would really recommend testing it with --dry-run beforehand. (see, feat: honor --ago cutoff when purging untagged manifests #517 for the feature PR I just made)

For further information, please kindly refer to the Automatically purge images from an Azure container registry article on Azure Learn