How to Migrate Google Cloud Registry Artifacts to Vultr Container Registry

Container Registry is used to store and manage container images. Migrating your container images from Google Artifact Registry to Vultr Container Registry offers several benefits, such as improved performance, cost efficiency, integration with Vultr's cloud infrastructure, and straightforward management with Vultr's intuitive Vultr Console interface.

Follow this guide to migrate your Google Artifact Registry images with the Docker Artifact format to the Vultr Container Registry. You will migrate all the images and verify data integrity post-migration.

Prerequisites

Before you begin:

• Have access to an Ubuntu 24.04 based server as a non-root sudo user to use as the migration workstation.
• Install Docker on your migration workstation to manage container images.
• Install gcloud CLI and initialize it with access to your GCP project.
• Provision a Vultr Container Registry to use as your destination Registry.
• Assign appropriate roles to your User account or Service account to access your Google Artifact Registry.

Prepare the Source Google Cloud Artifact Registry

In this section, you configure access credentials for your Google Artifact Registry with Docker. There are several methods to configure Google Artifact Registry authentication with Docker. This guide uses the gcloud CLI credential helper.

Follow the steps below on your Ubuntu machine to configure the access credentials for your Google Artifact Registry with Docker.

1. Add your non-root sudo user to the Docker group to grant permission to run the docker command.

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   $ sudo usermod -a -G docker $USER

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2. Authenticate Docker with your Google Artifact Registry.

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   $ gcloud auth configure-docker europe-central2-docker.pkg.dev

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   Replace europe-central2 with the location of your Google Artifact Registry.

   Example output:

   Adding credentials for: europe-central2-docker.pkg.dev
   After update, the following will be written to your Docker config file located at 
   [/home/linuxuser/.docker/config.json]:
    {
     "credHelpers": {
       "europe-central2-docker.pkg.dev": "gcloud"
    }
   }
   
   
   Do you want to continue (Y/n)?

   Enter Y at the prompt to continue.

Now your Docker client can connect to your Google Artifact Registry.

Set Up the Vultr Container Registry

Follow the steps below to authenticate your workstation with the Vultr Container Registry.

1. Log in to your Vultr Console.

2. Choose the newly provisioned Vultr Container Registry.

   

3. Copy the login command from the Overview page.

   

   Also, note the Username and API Key values.

4. Run the copied command to authenticate with your Vultr Container Registry. For example:

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   $ docker login <vultr_registry_url> --username <your_vultr_username> --password <your_vultr_password>

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   Example output indicating successful login:

   WARNING! Using --password via the CLI is insecure. Use --password-stdin.
   
   WARNING! Your credentials are stored unencrypted in '/home/linuxuser/.docker/config.json'.
   ...
   Login Succeeded

Migrate Repositories From the Google Cloud Artifact Registry to the Vultr Container Registry Using Docker

Follow the steps below to migrate all container images with all tags from your Google Artifact Registry to your Vultr Container Registry.

1. List the active registries.

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   $ gcloud artifacts repositories list

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   Example output:

   Listing items under project project-abc123, across all locations.
   
   ARTIFACT_REGISTRY
   
   REPOSITORY     FORMAT  MODE                 DESCRIPTION  LOCATION         LABELS  ENCRYPTION         CREATE_TIME           UPDATE_TIME           SIZE (MB)
   example-repo   DOCKER  STANDARD_REPOSITORY               europe-central2          Google-managed key  2025-02-11T18:58:05   2025-02-12T16:38:05   3.475
   

   Note the location of your source repository, for instance, europe-central2.

2. Create a new file named pull_images.sh.

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   $ nano pull_images.sh

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3. Add the following code to the pull_images.sh. Assign the variables PROJECT_ID, LOCATION, and REPO with your Google Cloud project ID, the location of your Google Artifact Registry, and its name as values.

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   #!/bin/bash
   
   GCP_PROJECT_ID="project-abc123"
   LOCATION="europe-central2"
   GCP_REPO="example-repo"
   HOST="${LOCATION}-docker.pkg.dev"
   
   for image in $(gcloud artifacts docker images list "${HOST}/${GCP_PROJECT_ID}/${GCP_REPO}" --format="value(IMAGE)"); do
       for tag in $(gcloud artifacts docker tags list "${image}" --format="value(TAG)" 2>/dev/null); do
           docker pull "${image}:${tag}"
       done
   done

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   The script above automatically downloads all images and their tags from your artifact registry to your migration workstation.

   Save and exit the file.

4. Make the pull_images.sh file executable.

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   $ chmod +x pull_images.sh

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5. Run the script to pull all GCP images.

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   $ ./pull_images.sh

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6. Create a new file named push_images.sh.

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   $ nano push_images.sh

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7. Add the following code to the push_images.sh file. Replace the value ams.vultrcr.com/example for the variable VULTR_REGISTRY_URL with your Vultr Container Registry URL, without the https:// prefix at the beginning of the URL.

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   #!/bin/bash
   GCP_HOST="europe-central2-docker.pkg.dev"
   GCP_PROJECT_ID="project-abc123"
   GCP_REPO="example-repo"
   VULTR_REGISTRY_URL="ams.vultrcr.com/example"
   
   for image in $(docker images --format "{{.Repository}}:{{.Tag}}" | grep "^${GCP_HOST}/${GCP_PROJECT_ID}/${GCP_REPO}"); do
       
       IMAGE_BASENAME=$(basename "${image}" | cut -d: -f1)
       IMAGE_TAG=$(basename "${image}" | cut -d: -f2)
   
       NEW_IMAGE="${VULTR_REGISTRY_URL}/${IMAGE_BASENAME}:${IMAGE_TAG}"
       
       echo "--- Migrating ${IMAGE_BASENAME}:${IMAGE_TAG} ---"
   
       docker tag "${image}" "${NEW_IMAGE}"
       docker push "${NEW_IMAGE}"
       
       echo "Successfully migrated to ${NEW_IMAGE}"
       echo ""
   done

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   The script above finds local Docker images that originate from the specified Google Artifact Registry. It then automatically retags each image for your Vultr Container Registry and pushes it to the new destination.

   Save and exit the file.

8. Make the push_images.sh file executable.

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   $ chmod +x push_images.sh

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9. Run the script to push the images to the Vultr Container Registry.

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   $ ./push_images.sh

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Verify and Test the Vultr Container Registry Images

To ensure the integrity of transferred images, you can compare the SHA256 digests of the images. In this section, you will use a Bash script to automatically compare the digests of the images in the Google Cloud Artifact Registry with the Vultr Container Registry. Follow the steps below to verify the integrity.

1. Create a new file named integrity_check.sh.

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   $ nano integrity_check.sh

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2. Add the following code to the file. Provide GCP_LOCATION, GCP_REPO, GCP_PROJECT_ID, and VULTR_REGISTRY_URL variables with your values.

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   #!/bin/bash
   
   GCP_LOCATION="europe-central2"
   GCP_REPO="example-repo"
   VULTR_REGISTRY_URL="ams.vultrcr.com/example"
   GCP_PROJECT_ID="project-abc123"
   GCP_HOST="${GCP_LOCATION}-docker.pkg.dev"
   
   for image in $(docker images --format "{{.Repository}}:{{.Tag}}" | grep "^${GCP_HOST}/${GCP_PROJECT_ID}/${GCP_REPO}"); do
       
       IMAGE_BASENAME=$(basename "${image}" | cut -d: -f1)
       IMAGE_TAG=$(basename "${image}" | cut -d: -f2)
   
       GCP_IMAGE="${image}"
       VULTR_IMAGE="${VULTR_REGISTRY_URL}/${IMAGE_BASENAME}:${IMAGE_TAG}"
   
       echo "--- Verifying: ${IMAGE_BASENAME}:${IMAGE_TAG} ---"
   
       docker pull "$GCP_IMAGE" > /dev/null 2>&1
       docker pull "$VULTR_IMAGE" > /dev/null 2>&1
   
       GCP_DIGEST=$(docker inspect --format='{{index .RepoDigests 0}}' "$GCP_IMAGE" | awk -F'@' '{print $2}' 2>/dev/null)
       VULTR_DIGEST=$(docker inspect --format='{{index .RepoDigests 0}}' "$VULTR_IMAGE" | awk -F'@' '{print $2}' 2>/dev/null)
       
       if [[ -z "$GCP_DIGEST" || -z "$VULTR_DIGEST" ]]; then
           echo "Error: Could not retrieve digest for one or both images from the local daemon."
       elif [[ "$GCP_DIGEST" == "$VULTR_DIGEST" ]]; then
           echo "Integrity verified, digests match: ${GCP_DIGEST}"
       else
           echo "Digests are different!"
           echo "GCP Digest (local):   $GCP_DIGEST"
           echo "Vultr Digest (local): $VULTR_DIGEST"
       fi
       echo ""
   done

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   The script above finds local Docker images that originate from the specified Google Artifact Registry. For each image tag, it pulls both the Google Artifact Registry and corresponding Vultr Container Registry versions to ensure they are present locally. It then calculates their SHA256 digests from the local Docker daemon and compares them. If there are no differences, it indicates a successful transfer without errors.

3. Make the script executable.

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   $ chmod +x integrity_check.sh

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4. Run the script.

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   $ ./integrity_check.sh

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   Example output indicating a successful transfer:

   Integrity verified, digests match: sha256:7b9b6a044d921dfcaea2a843ff19d725948590352198f93cb878fd2c19d7ba3c

Cutover to the Vultr Container Registry

This section describes transitioning your applications and workflows to use the new registry. Follow the recommendations below to cut over your containers to the Vultr Container Registry.

1. Update your Docker files to use the Vultr Container Registry.

   • Before:

     app:
         image: europe-central2-docker.pkg.dev/example-project/example-repo/my-app:1.0.0

   • After:

     app:
         image: <vultr_registry_url>/my-app:1.0.0

     Replace <vultr_registry_url> with your Vultr Container registry URL without the https:// prefix.

2. Update your Kubernetes Deployments files.

   • Before:

     apiVersion: apps/v1
     kind: Deployment
     metadata:
     name: my-app
     spec:
     replicas: 3
     template:
         spec:
         containers:
         - name: my-app
             image: europe-central2-docker.pkg.dev/project-abc123/example-repo/my-app:1.0.0

   • After:

     apiVersion: apps/v1
     kind: Deployment
     metadata:
     name: my-app
     spec:
     replicas: 3
     template:
         spec:
         containers:
         - name: my-app
             image: <vultr_registry_url>/my-app:1.0.0

     Replace <vultr_registry_url> with your Vultr Container registry URL without the https:// prefix.

3. After transferring your production workloads to the Vultr Container Registry, you may delete the old GCP registry to avoid unnecessary billing costs.

Conclusion

You've migrated your container images from your Google Artifact Registry to your Vultr Container Registry and verified post-migration data integrity. For more information on Vultr Container Registry, refer to the official Vultr Container Registry documentation.