Configure an external container registry

To use an external container registry with Kalix, you need to give Kalix permissions to connect to your registry. To add credentials for your container registry to Kalix, you can use the Kalix CLI or the Kalix Console.

If the container registry you’re using does not require authentication, you don’t have to add any credentials. Kalix will automatically pull the container image using the URL you use to deploy your service.

There are four parameters you need to specify, depending on the registry you want to connect to:

  • Server: The first part of the container image URL. For example, if your image is at, the server is (mandatory).

  • Username: The username (optional).

  • Email: The email address (optional).

  • Password: The password (mandatory).

Use the kalix docker add-credentials command.

kalix docker add-credentials --docker-server <my-server> \ (1)
  --docker-username <my-username> \ (2)
  --docker-email <my-email> \ (3)
  --docker-password <my-password> (4)
1 Server
2 Username
3 Email
4 Password

Listing credentials

To list all container registry credentials for your Kalix project, you can use the Kalix CLI or the Kalix Console. For security purposes, neither the CLI nor the Console will show the password of the configured registry.

Use the kalix docker list-credentials command:

kalix docker list-credentials

The results should look something like:

ID                                     SERVER              USERNAME    EMAIL
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx   _json_key

Removing credentials

To remove container registry credentials from your Kalix project, you can use the Kalix CLI or the Kalix Console.

Use the 'ID' returned from the kalix docker list-credentials command as the ID in the kalix docker delete-credentials command:

kalix docker delete-credentials <credentials-id>

Supported external registries

Private container registries

To connect your Kalix project to private or self-hosted container registries, the parameters you need are:

  • Server: The full URL of your container registry, including the API version (like

  • Username: Your username.

  • Email: Your email address.

  • Password: Your password.

Docker Hub

To connect your Kalix project to Docker Hub, the parameters you need are:

  • Server:

  • Username: Your Docker Hub username.

  • Email: Your Docker Hub email address.

  • Password: Your Docker Hub password or Personal Access Token.

When you use the Kalix Console, you don’t need to provide the Server URL.

Limits on unauthenticated and free usage

Docker has rate limits new tab for unauthenticated and free Docker Hub usage. For unauthenticated users, pull rates are limited based on IP address (anonymous, or unauthenticated, users have a limit of 100 container image pulls per 6 hours per IP address). Kalix leverages a limited set of IP addresses to connect to Docker Hub. This means that unauthenticated image pulls might be rate limited. The limit for unauthenticated pulls is shared by all users of the Kalix platform.

Google Container Registry

To connect your Kalix project to Google Container Registry (GCR), you’ll need:

  • An active Google Cloud Platform account.

  • The Registry API enabled on your Google Cloud project.

  • The ID that corresponds with your GCP project.

    1. Create the service account.

      In the following example the service account is named kalix-docker-reader. Run the create command in your terminal if you have the GCP shell tools installed. Or, run the command from the browser using Cloud Shell Terminal in the Google Cloud Platform (GCP) project.

      gcloud iam service-accounts create kalix-docker-reader
    2. Grant the GCP storage object viewer role to the service account.

      In the following example, replace <gcp-project-id> with the GCP project ID.

      gcloud projects add-iam-policy-binding <gcp-project-id> \
        --member "serviceAccount:kalix-docker-reader@<gcp-project-id>" \
        --role "roles/storage.objectViewer"
    3. Generate the service account _json_key.

      gcloud iam service-accounts keys create keyfile.json \
        --iam-account kalix-docker-reader@<gcp-project-id>
    4. Configure your Kalix project to use these credentials, by passing the contents of the key file as the password.

      kalix docker add-credentials --docker-server \
        --docker-username _json_key \
        --docker-email \
        --docker-password "$(cat keyfile.json)"
      Find detailed configuration instructions in the Google documentation new tab.

Azure Container Registry

To connect your Kalix project to Azure Container Registry (ACR), the parameters you need are:

  • Server: <registry name>

  • Password: The password is based on the "service principal." To create a service principal (like kalix-docker-reader) run the command below.

    ACR_REGISTRY_ID=$(az acr show —name kalix-registry —query id —output tsv)
    SP_PASSWD=$(az ad sp create-for-rbac --name http://kalix-docker-reader --scopes $ACR_REGISTRY_ID --role acrpull --query password --output tsv)
  • Username: The username is the application ID of the "service principal." To retrieve the ID, run the command below.

    SP_APP_ID=$(az ad sp show —id http://kalix-docker-reader —query appId —output tsv)

When you use the Kalix Console, you only need to fill in the registry name for the Server URL.