Add remote tag to a docker image

Question

On a private registry (myregistry.com), say I have an image tagged with 'v1.2.3'. I then push it by:

docker push myregistry.com/myimage:v1.2.3

If I want to associate another tag, say 'staging', and push that tag to my registry, I can:

docker tag myregistry.com/myimage:v1.2.3 myregistry.com/myimage:staging docker push myregistry.com/myimage:staging 

Though this works, the second docker push still runs through each image, attempting to push it (albeit skipping upload). Is there a better way just to add a remote tag?

Answer 1

The way you've stated, docker tag ...; docker push ... is the best way to add a tag to an image and share it.

In the specific example you've given, both tags were in the same repo (myregistry.com/myimage). In this case you can just docker push myregistry.com/myimage and by default the docker daemon will push all the tags for the repo at the same time, saving the iteration over layers for shared layers.

You can use the same process (docker tag ...; docker push ...) to tag images between repositories as well, e.g.

docker tag myregistry.com/myimage:v1.2.3 otherregistry.com/theirimage:v2 docker push otherregistry.com/theirimage