docker pull through cache for private registry not working

Question

I tried the pull through cache docker released in registry 2.1.1 release with docker 1.8. on CentOS7.1 However, I followed these websites and it doesn't act as mirroring, any inputs would be much appreciated. I hope this is the right way of configuring registry service and passing docker daemon arguments.

Websites: https://github.com/docker/distribution/blob/master/docs/mirror.md http://docs.master.dockerproject.org/articles/registry_mirror/

Steps:

1. I added arguments to pass to docker daemon process and restarted it:

   # /etc/sysconfig/docker 
   # 
   # Other arguments to pass to the docker daemon process 
   # These will be parsed by the sysv initscript and appended 
   # to the arguments list passed to docker -d
   OPTIONS="--registry-mirror=http://localhost:5000" 
   

2. Added registry config and mounted to the container:

   version: 0.1
   log:
     fields:
       service: registry
   storage:
       cache:
           blobdescriptor: inmemory
       filesystem:
           rootdirectory: /var/lib/registry
   http:
       addr: :5000
       headers:
           X-Content-Type-Options: [nosniff]
   health:
     storagedriver:
       enabled: true
       interval: 10s
       threshold: 3
   proxy:
     remoteurl: https://registry-1.docker.io
   

3. Launched registry container

   docker run -d -p 5000:5000 --restart=always --name registry-mirror -v /opt/docker-registry/local/images:/var/lib/registry -v /opt/docker-registry/local/config/config.yml:/etc/docker/registry/config.yml -e STANDALONE=false -e MIRROR_SOURCE=https://registry-1.docker.io -e MIRROR_SOURCE_INDEX=https://index.docker.io registry:2.1.1
   

4. Tested pull through cache with commands as follows:

   With my mirror running, pull an image that I haven't pulled before (using time to time it)

   Pulls from docker hub as configured as MIRROR_SOURCE

   $ time docker pull busybox:latest
   

   Remove the image from local machine

   $ docker rmi busybox:latest
   

   Finally, this should re-pull the image from cache, which is not working in my case, rather pulling from docker hub instead.

   $ time docker pull busybox:latest
   

   I also tried looking at the mounted images volume folder in my host file system, couldn't find it.

   $ ls /opt/docker-registry/local/images/docker/registry/v2/repositories/
   

   Tried making rest api call to that new image, returns error message instead:

   $ curl http://localhost:5000/v2/busybox/tags/list     
       {"errors":[{"code":"NAME_UNKNOWN","message":"repository name not known to registry","detail":{"name":"busybox"}}]}
   

Answer 1

It worked for me using ...

docker run -p 5000:5000 \
    -e STANDALONE=false \
    -e MIRROR_SOURCE=https://registry-1.docker.io \
    -e MIRROR_SOURCE_INDEX=https://index.docker.io \
    -e "REGISTRY_LOG_LEVEL=debug" \
    -e "REGISTRY_REDIRECT_DISABLE=true" \
    -v /var/lib/registry:/var/lib/registry \
    --name registry-cache-latest \
    registry

.. and then pointintg --registry-mirror to the http server, not https.