catalog/skopeo

Skopeo

Skopeo is a command line tool for working with remote image registries. Skopeo doesn’t require a daemon to be running while performing its operations. In particular, the handy skopeo command called copy will ease the whole image copy operation. Without further ado, you can copy an image from a registry to another simply by running:

skopeo copy docker://internal.registry/myimage:latest /
docker://production.registry/myimage:v1.0

The copy command will take care of copying the image from internal.registry to production.registry

If your production registry requires credentials to login in order to push the image, skopeo can handle that as well.

skopeo copy --dest-creds prod_user:prod_pass docker://internal.registry/myimage:latest /
docker://production.registry/myimage:v1.0

The same goes for credentials for the source registry (internal.registry) by using the --src-creds flag.

It is also useful for copying images between two remote docker registries, such as the registries of two different OpenShift clusters, as shown

skopeo copy docker://busybox:latest oci:busybox_ocilayout:latest

Skopeo copy isn’t limited to remote containers registries. The image prefix docker:// from the above command define the transport to be used when handling the image.

There are others also similar to that:

• atomic
• containers-storage
• dir
• docker
• docker-daemon
• docker-tar
• oci
• ostree

This task can be used to copy one or more than one images to-and fro various storage mechanisms.

This task uses image from this Dockerfile.

Install the Task

kubectl apply -f https://raw.githubusercontent.com/tektoncd/catalog/v1beta1/skopeo/skopeo.yaml

Parameters

• srcImageURL: The URL of the image to be copied to the destination registry.
• destImageURL: The URL of the image where the image from source should be copied to.

Workspace

• images-url: To mount file containing multiple source and destination images registries URL, which is mounted as configMap.

Secrets and ConfigMap

• Secret to provide the credentials of the source and destination registry where the image needs to be copied from and to.

• ConfigMap to provide support for copying multiple images, this contains file url.txt which stores images registry URL's.

  This example can help to use secrets for providing credentials of image registries.

Usage

This task will use the Service Account with access to the secrets containing source and destination image registry credentials, this will authorize it to the respective image registries.

In case of multiple source and destination image registries that needs to be copied to and fro, a file named url.txt should be created containing all the source and destination image registries URL seperated by a space and each set of images should be written in the new line, as shown below.

docker://quay.io/temp/kubeconfigwriter:v1 docker://quay.io/skopeotest/kube:v1
docker://quay.io/temp/kubeconfigwriter:v2 docker://quay.io/skopeotest/kube:v2

ConfigMap should be created using this file. Following command can be used to create configMap from the file.

kubectl create configmap image-configmap --from-file=url.txt

In case there is only one source and destination image that needs to be copied then, Source and destination image URL needs to be provided in the input params of the task.

This will result in the image getting copied from the source registry to the destination registry.

This will guide the user to use service account for authorization to image registries.

See here for example of TaskRun.

Note

• Source credentials are only required, if the source image registry needs authentication to pull the image, whereas Destination credentials are always required.

• In case of multiple source and destination images, secret containing credentials of all the image registries must be added to the service account and configMap containing url.txt should be mounted into the workspace, as shown

  workspaces:
    - name: images-url
      configmap:
        name: image-configmap
  

• If there is only one source and destination image registry URL, then emptyDir needs to be mounted in the workspace as shown below:

  workspaces:
    - name: images-url
      emptyDir: {}