Which command publishes a locally built image to quay.io using skopeo?

Which command publishes a locally built image to quay.io using skopeo?

• A. docker push quay.io/<user>/<name>
• B. oc import-image <name> --from quay.io/<user>/<name>
• C. sudo skopeo copy containers-storage:localhost/<name> docker://quay.io/<user>/<name>
• D. skopeo copy docker://quay.io/<user>/<name> containers-storage:localhost/<name>

Answer: (C)

Transferring an image from local storage to a remote registry with skopeo uses the copy command, taking the local image as the source and the registry as the destination. The local image lives in container storage, referenced as containers-storage:localhost/<name>, while the target registry uses the docker:// transport, such as docker://quay.io/<user>/<name>. Executing sudo skopeo copy containers-storage:localhost/<name> docker://quay.io/<user>/<name> copies the locally built image from your machine up to quay.io, effectively publishing it. This works because skopeo copy can move images between storages and registries without a daemon, and the docker:// transport is what communicates with the registry API to push the image. The other options either rely on Docker push (not using skopeo), import an image into OpenShift (not publishing to quay.io), or copy in the reverse direction (pulling from quay.io back into local storage), which isn’t publishing to the registry.

Transferring an image from local storage to a remote registry with skopeo uses the copy command, taking the local image as the source and the registry as the destination. The local image lives in container storage, referenced as containers-storage:localhost/, while the target registry uses the docker:// transport, such as docker://quay.io//. Executing sudo skopeo copy containers-storage:localhost/ docker://quay.io// copies the locally built image from your machine up to quay.io, effectively publishing it.

This works because skopeo copy can move images between storages and registries without a daemon, and the docker:// transport is what communicates with the registry API to push the image. The other options either rely on Docker push (not using skopeo), import an image into OpenShift (not publishing to quay.io), or copy in the reverse direction (pulling from quay.io back into local storage), which isn’t publishing to the registry.