[feature] add ability to specify prefix to pull offline/local images from

[Jeff Hillman]

In an offline/local deploy of kubernetes, customer create their own private docker repo/registry.

In these cases, customers are not always wanting to keep the same expected labels for proper organization per team/group/usage.

Specifically, something like

k8s.gcr.io/pause:3.1
docker.io/library/busybox:1.29

they might want to lump them together for

k8s-deploy/pause:3.1
k8s-deploy/busybox:1.29

The current tooling does not allow for this. We can specify an offline/private registry (in some cases), but not a prefix in that registry.

[Kevin W Monroe (kwmonroe)]

I think we can find a nice way to truncate image prefixes, but we would then expect all images to be in a flat structure at the configured image-registry.

That may cover a majority of private registry users, but I think we'll have some that want certain images (maybe storage-related) to come from a ./k8s-storage prefix and others (maybe ingress) to come from a ./k8s-ingress prefix. That scenario would be more difficult to accommodate -- the only solution I have for that today would be to expose config for every image that could possibly be used in a CDK deploy, and that's a mess.

Thanks for the bug report; it's certainly something we'll hash out.

[Mike Wilson (knobby)]

You can include a prefix on the image-registry config option. It wouldn’t smash the paths currently, but it would certainly add to it. Set to 10.0.0.1:5000/my-images would look for 10.0.0.1:5000/my-images/pause:3.1 and 10.0.0.1:5000/my-images/library/busybox:1.29. This may not be 100% what is desired, but it is available today.

[Joe Guo (guoqiao)]

According to doc[0], add a registry as "*" may do the work:

     [plugins.cri.registry]
      [plugins.cri.registry.mirrors]
        ...
        [plugins.cri.registry.mirrors."*"]
          endpoint = ["http://34.235.169.214:5000"]
        ...

The `*` is registry host, which is also image prefix, it will match any image.

[0]: https://github.com/containerd/cri/blob/master/docs/registry.md#configure-registry-endpoint