# Docker Registries

The `dockerRegistries` key can specify additional Docker Registries to authenticate against during the build and deploy processes. This is often used during a build in order to build from a private base image.

These registry credentials are also used during deployment to allow your cluster to pull additional images from a private repository. 

{% hint style="info" %}
If you are using private images that are not built by Preview as part of your deployment, you will need to provide authentication to your Docker Registry in this way.
{% endhint %}

| Key                                 | Description                                                                                                            |
| ----------------------------------- | ---------------------------------------------------------------------------------------------------------------------- |
| `dockerRegistries[].service`        | The type of Docker registry this is. This determines how Preview authenticates. Current options are \[`docker`, `aws`] |
| `dockerRegistries[].url`            | The URL of the Docker registry                                                                                         |
| `dockerRegistries[].username`       | \[`docker` only] Account username                                                                                      |
| `dockerRegistries[].password`       | \[`docker` only] Account password                                                                                      |
| `dockerRegistries[].AWS_ACCESS_KEY` | \[`aws` only] Access Key of IAM account                                                                                |
| `dockerRegistries[].AWS_SECRET_KEY` | \[`aws` only] Secret Key of IAM account                                                                                |
| `dockerRegistries[].AWS_ACCOUNT`    | \[`aws` only] AWS Account ID of registry                                                                               |
| `dockerRegistries[].AWS_REGION`     | \[`aws` only] AWS Region of registry                                                                                   |