How to delete images from a private docker registr

Question

I run a private docker registry, and I want to delete all images but the latest from a repository. I don't want to delete the entire repository, just some of the images inside it. The API docs don't mention a way to do this, but surely it's possible?

Answer 1

This docker image includes a bash script that can be used to remove images from a remote v2 registry : https://hub.docker.com/r/vidarl/remove_image_from_registry/

Answer 2

Simple ruby script based on this answer: registry_cleaner.

You can run it on local machine:

./registry_cleaner.rb --host=https://registry.exmpl.com --repository=name --tags_count=4

And then on the registry machine remove blobs with /bin/registry garbage-collect /etc/docker/registry/config.yml.

Answer 3

Problem 1

You mentioned it was your private docker registry, so you probably need to check Registry API instead of Hub registry API doc, which is the link you provided.

Problem 2

docker registry API is a client/server protocol, it is up to the server's implementation on whether to remove the images in the back-end. (I guess)

DELETE /v1/repositories/(namespace)/(repository)/tags/(tag*)

Detail explanation

Below I demo how it works now from your description as my understanding for your questions.

You run you run private docker registry, I use the default one and listen in 5000 port

docker run -d -p 5000:5000 registry

Then I tag the local image and push into it.

$ docker tag ubuntu localhost:5000/ubuntu
$ docker push localhost:5000/ubuntu
The push refers to a repository [localhost:5000/ubuntu] (len: 1)
Sending image list
Pushing repository localhost:5000/ubuntu (1 tags)
511136ea3c5a: Image successfully pushed
d7ac5e4f1812: Image successfully pushed
2f4b4d6a4a06: Image successfully pushed
83ff768040a0: Image successfully pushed
6c37f792ddac: Image successfully pushed
e54ca5efa2e9: Image successfully pushed
Pushing tag for rev [e54ca5efa2e9] on {http://localhost:5000/v1/repositories/ubuntu/tags/latest}

After that you can use Registry API to check it exists in your private docker registry

$ curl -X GET localhost:5000/v1/repositories/ubuntu/tags
{"latest": "e54ca5efa2e962582a223ca9810f7f1b62ea9b5c3975d14a5da79d3bf6020f37"}

Now I can delete the tag using that API !!

$ curl -X DELETE localhost:5000/v1/repositories/ubuntu/tags/latest
true

Check again, the tag doesn't exist in your private registry server

$ curl -X GET localhost:5000/v1/repositories/ubuntu/tags/latest
{"error": "Tag not found"}

Answer 4

There are some clients (in Python, Ruby, etc) which do exactly that. For my taste, it isn't sustainable to install a runtime (e.g. Python) on my registry server, just to housekeep my registry!

---

So deckschrubber is my solution:

go get github.com/fraunhoferfokus/deckschrubber
$GOPATH/bin/deckschrubber

images older than a given age are automatically deleted. Age can be specified using -year, -month, -day, or a combination of them:

$GOPATH/bin/deckschrubber -month 2 -day 13 -registry http://registry:5000

---

UPDATE: here's a short introduction on deckschrubber.

Answer 5

This is really ugly but it works, text is tested on registry:2.5.1. I did not manage to get delete working smoothly even after updating configuration to enable delete. The ID was really difficult to retrieve, had to login to get it, maybe some misunderstanding. Anyway, the following works:

1. Login to the container

   docker exec -it registry sh
   

2. Define variables matching your container and container version:

   export NAME="google/cadvisor"
   export VERSION="v0.24.1"
   

3. Move to the the registry directory:

   cd /var/lib/registry/docker/registry/v2
   

4. Delete files related to your hash:

   find . | grep `ls ./repositories/$NAME/_manifests/tags/$VERSION/index/sha256`| xargs rm -rf $1
   

5. Delete manifests:

   rm -rf ./repositories/$NAME/_manifests/tags/$VERSION
   

6. Logout

   exit
   

7. Run the GC:

   docker exec -it registry  bin/registry garbage-collect  /etc/docker/registry/config.yml
   

8. If all was done properly some information about deleted blobs is shown.

Answer 6

Below Bash Script Deletes all the tags located in registry except the latest.

for D in /registry-data/docker/registry/v2/repositories/*; do
if [ -d "${D}" ]; then
    if [ -z "$(ls -A ${D}/_manifests/tags/)" ]; then
        echo ''
    else
        for R in $(ls -t ${D}/_manifests/tags/ | tail -n +2); do
            digest=$(curl -k -I -s -H -X GET http://xx.xx.xx.xx:5000/v2/$(basename  ${D})/manifests/${R} -H 'accept: application/vnd.docker.distribution.manifest.v2+json'  | grep Docker-Content-Digest | awk '{print $2}' )
            url="http://xx.xx.xx.xx:5000/v2/$(basename  ${D})/manifests/$digest"
            url=${url%$'\r'}
            curl -X DELETE -k -I -s   $url -H 'accept: application/vnd.docker.distribution.manifest.v2+json' 
        done
    fi
fi
done

After this Run

docker exec $(docker ps | grep registry | awk '{print $1}') /bin/registry garbage-collect /etc/docker/registry/config.yml