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Import container images to a container registry

  • Artikkeli

You can easily import (copy) container images to an Azure container registry, without using Docker commands. For example, import images from a development registry to a production registry, or copy base images from a public registry.

Azure Container Registry handles many common scenarios to copy images and other artifacts from an existing registry:

  • Import images from a public registry

  • Import images or OCI artifacts including Helm 3 charts from another Azure container registry, in the same, or a different Azure subscription or tenant

  • Import from a non-Azure private container registry

Image import into an Azure container registry has the following benefits over using Docker CLI commands:

  • If your client environment doesn't need a local Docker installation, you can Import any container image, regardless of the supported OS type.

  • If you import multi-architecture images (such as official Docker images), images for all architectures and platforms specified in the manifest list get copied.

  • If you have access to the target registry, you don't require the registry's public endpoint.

Important

  • Importing images requires the external registry support RFC 7233. We recommend using a registry that supports RFC 7233 ranges while using az acr import command with the registry URI to avoid failures.

Limitations

  • The maximum number of manifests for an imported image is 50.
  • The maximum layer size for an image imported from a public registry is 2 GiB.

To import container images, this article requires that you run the Azure CLI in Azure Cloud Shell or locally (version 2.0.55 or later recommended). Run az --version to find the version. If you need to install or upgrade, see Install Azure CLI.

Note

If you need to distribute identical container images across multiple Azure regions, Azure Container Registry also supports geo-replication. By geo-replicating a registry (Premium service tier required), you can serve multiple regions with identical image and tag names from a single registry.

Important

Changes to image import between two Azure container registries have been introduced as of January 2021:

  • Import to or from a network-restricted Azure container registry requires the restricted registry to allow access by trusted services to bypass the network. By default, the setting is enabled, allowing import. If the setting isn't enabled in a newly created registry with a private endpoint or with registry firewall rules, import will fail.
  • In an existing network-restricted Azure container registry that is used as an import source or target, enabling this network security feature is optional but recommended.

Prerequisites

If you don't already have an Azure container registry, create a registry. For steps, see Quickstart: Create a private container registry using the Azure CLI.

To import an image to an Azure container registry, your identity must have write permissions to the target registry (at least Contributor role, or a custom role that allows the importImage action). See Azure Container Registry roles and permissions.

Import from a public registry

Important

To import from a public registry to a network-restricted Azure container registry requires the restricted registry to allow access by trusted services to bypass the network.By default, the setting is enabled, allowing import. If the setting isn't enabled in a newly created registry with a private endpoint or with registry firewall rules, import will fail.

Import from Docker Hub

For example, use the az acr import command to import the multi-architecture hello-world:latest image from Docker Hub to a registry named myregistry. Because hello-world is an official image from Docker Hub, this image is in the default library repository. Include the repository name and optionally a tag in the value of the --source image parameter. (You can optionally identify an image by its manifest digest instead of by tag, which guarantees a particular version of an image.)

az acr import \
  --name myregistry \
  --source docker.io/library/hello-world:latest \
  --image hello-world:latest

You can verify that multiple manifests are associated with this image by running the az acr manifest list-metadata command:

az acr manifest list-metadata \
  --name hello-world \
  --registry myregistry

To import an artifact by digest without adding a tag:

az acr import \
   --name myregistry \
   --source docker.io/library/hello-world@sha256:abc123 \
   --repository hello-world

If you have a Docker Hub account, we recommend that you use the credentials when importing an image from Docker Hub. Pass the Docker Hub user name and the password or a personal access token as parameters to az acr import. The following example imports a public image from the tensorflow repository in Docker Hub, using Docker Hub credentials:

az acr import \
  --name myregistry \
  --source docker.io/tensorflow/tensorflow:latest-gpu \
  --image tensorflow:latest-gpu
  --username <Docker Hub user name>
  --password <Docker Hub token>

Import from Microsoft Container Registry

For example, import the ltsc2019 Windows Server Core image from the windows repository in Microsoft Container Registry.

az acr import \
--name myregistry \
--source mcr.microsoft.com/windows/servercore:ltsc2019 \
--image servercore:ltsc2019

Import from an Azure container registry in the same AD tenant

You can import an image from an Azure container registry in the same AD tenant using integrated Microsoft Entra permissions.

  • Your identity must have Microsoft Entra permissions to read from the source registry (Reader role) and to import to the target registry (Contributor role, or a custom role that allows the importImage action).

  • The registry can be in the same or a different Azure subscription in the same Active Directory tenant.

  • Public access to the source registry is disabled. If public access is disabled, specify the source registry by resource ID instead of by registry login server name.

  • The source registry and/or the target registry with a private endpoint or registry firewall rules must ensure the restricted registry allows trusted services to access the network.

Import from a registry in the same subscription

For example, import the aci-helloworld:latest image from a source registry mysourceregistry to myregistry in the same Azure subscription.

az acr import \
  --name myregistry \
  --source mysourceregistry.azurecr.io/aci-helloworld:latest \
  --image aci-helloworld:latest

The following example imports the aci-helloworld:latest image to myregistry from a source registry mysourceregistry in which access to the registry's public endpoint is disabled. Supply the resource ID of the source registry with the --registry parameter. Notice that the --source parameter specifies only the source repository and tag, not the registry login server name.

az acr import \
  --name myregistry \
  --source aci-helloworld:latest \
  --image aci-helloworld:latest \
  --registry /subscriptions/aaaa0a0a-bb1b-cc2c-dd3d-eeeeee4e4e4e/resourceGroups/sourceResourceGroup/providers/Microsoft.ContainerRegistry/registries/mysourceregistry

The following example imports an image by manifest digest (SHA-256 hash, represented as sha256:...) instead of by tag:

az acr import \
  --name myregistry \
  --source mysourceregistry.azurecr.io/aci-helloworld@sha256:123456abcdefg

Import from a registry in a different subscription

Note

To import an image from one registry to another, the source and target registries must ensure that both regions are registered for Azure Container Registry (ACR) under the subscription’s resource providers.

In the following example, mysourceregistry is in a different subscription from myregistry in the same Active Directory tenant. Supply the resource ID of the source registry with the --registry parameter. Notice that the --source parameter specifies only the source repository and tag, not the registry login server name.

az acr import \
  --name myregistry \
  --source aci-helloworld:latest \
  --image aci-hello-world:latest \
  --registry /subscriptions/aaaa0a0a-bb1b-cc2c-dd3d-eeeeee4e4e4e/resourceGroups/sourceResourceGroup/providers/Microsoft.ContainerRegistry/registries/mysourceregistry

Import from a registry using service principal credentials

To import from a registry that you can't access using integrated Active Directory permissions, you can use service principal credentials (if available) to the source registry. Supply the appID and password of an Active Directory service principal that has ACRPull access to the source registry. Using a service principal is useful for build systems and other unattended systems that need to import images to your registry.

az acr import \
  --name myregistry \
  --source sourceregistry.azurecr.io/sourcerrepo:tag \
  --image targetimage:tag \
  --username <SP_App_ID> \
  --password <SP_Passwd>

Import from an Azure container registry in a different AD tenant

To import from an Azure container registry in a different Microsoft Entra tenant, specify the source registry by login server name, and provide credentials that enable pull access to the registry.

  • Cross-tenant import over public access disabled registry is not supported.

Cross-tenant import with username and password

For example, use a repository-scoped token and password, or the appID and password of an Active Directory service principal that has ACRPull access to the source registry.

az acr import \
  --name myregistry \
  --source sourceregistry.azurecr.io/sourcerrepo:tag \
  --image targetimage:tag \
  --username <SP_App_ID> \
  --password <SP_Passwd>

Cross-tenant import with access token

  • Cross-tenant import over public access disabled registry is not supported.

To access the source registry using an identity in the source tenant that has registry permissions, you can get an access token:

# Login to Azure CLI with the identity, for example a user-assigned managed identity
az login --identity --username <identity_ID>

# Get access token returned by `az account get-access-token`
az account get-access-token

In the target tenant, pass the access token as a password to the az acr import command. The source registry specifies the login server name. Notice that no username is needed in this command:

az acr import \
  --name myregistry \
  --source sourceregistry.azurecr.io/sourcerrepo:tag \
  --image targetimage:tag \
  --password <access-token>

Import from a non-Azure private container registry

Import an image from a non-Azure private registry by specifying credentials that enable pull access to the registry. For example, pull an image from a private Docker registry:

az acr import \
  --name myregistry \
  --source docker.io/sourcerepo/sourceimage:tag \
  --image sourceimage:tag \
  --username <username> \
  --password <password>

Next steps

In this article, you learned about importing container images to an Azure container registry from a public registry or another private registry.

  • For additional image import options, see the az acr import command reference.