CODEWITHSUNDEEP
docker
Juicy
Juicy

Reputation: 12520

Can you tag a docker image in a remote repository without pulling it?

I occasionally need to do some manual promotion for a docker image.

The flow I use is:

$ docker pull registry.digitalocean.com/foo/bar:dev-123
$ docker tag registry.digitalocean.com/foo/bar:dev-123 registry.digitalocean.com/foo/bar:prd-123
$ docker push registry.digitalocean.com/foo/bar:prd-123

This involves pulling the image to my local host, tagging it there, and pushing it up again.

It seems to me there should be a way of tagging the image in the remote repository without the above faff, but I couldn't find an answer on Google.

Upvotes: 10

Views: 4959

Answers (3)

tom
tom

Reputation: 22969

Docker Buildx now supports efficient copying (docs):

docker buildx imagetools create --tag NEWIMAGE OLDIMAGE

(credit)

Upvotes: 0

davidxxx
davidxxx

Reputation: 131346

This involves pulling the image to my local host, tagging it there, and pushing it up again.

It seems to me there should be a way of tagging the image in the remote repository without the above faff, but I couldn't find an answer on Google.

Fundamentally these 3 steps (pull/tag/push) are required if the registry is remote but there are some tricks to fast up that if the registry is own.

1.If the current docker host has the updated image in its local repository you can can skip the pull :

docker tag registry.digitalocean.com/foo/bar:dev-123 registry.digitalocean.com/foo/bar:prd-123
docker push registry.digitalocean.com/foo/bar:prd-123

2.If the remote registry is a private registry that you can connect to, you can strongly improve that (pulling and pushing may be slow according to the image size) by performing the task from the machine hosting that registry.
It would be only two quite fast steps now :

docker tag registry.digitalocean.com/foo/bar:dev-123 registry.digitalocean.com/foo/bar:prd-123
docker push registry.digitalocean.com/foo/bar:prd-123

3.If you cannot perform these tasks from that machine directly, you can still use the docker -H HOST way to connect to the remote Docker Daemon of that registry (if that is enabled of course):

docker -H registry.digitalocean.com tag registry.digitalocean.com/foo/bar:dev-123 registry.digitalocean.com/foo/bar:prd-123
docker -H registry.digitalocean.com  push registry.digitalocean.com/foo/bar:prd-123

For series of large images that I have to tag in private registries, I always favor these ways when possible.

Upvotes: 2

larsks
larsks

Reputation: 311606

You can do this using skopeo, like this:

skopeo copy docker://some/image:oldtag docker://some/image:newtag

For example, if I have:

$ skopeo list-tags docker://larsks/skopeo-example
{
    "Repository": "docker.io/larsks/skopeo-example",
    "Tags": [
        "latest"
    ]
}

I can run:

$ skopeo copy docker://larsks/skopeo-example:latest docker://larsks/skopeo-example:newtag
Getting image source signatures
Copying blob df20fa9351a1 skipped: already exists
Copying config 0bce593a08 [--------------------------------------] 0.0b / 741.0b
Writing manifest to image destination
Storing signatures

And now I have:

$ skopeo list-tags docker://larsks/skopeo-example
{
    "Repository": "docker.io/larsks/skopeo-example",
    "Tags": [
        "latest",
        "newtag"
    ]
}

Upvotes: 4

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