doc how to use custom domain for sdk

docs/vendor/custom-domains-using.md

@@ -1,6 +1,6 @@
 # Use Custom Domains
 
-This topic describes how to use the Replicated Vendor Portal to add and manage custom domains to alias the Replicated registry, the Replicated proxy registry, the Replicated app service, the Replicated Enterprise Portal and the Replicated Download Portal.
+This topic describes how to use the Replicated Vendor Portal to add and manage custom domains to alias Replicated endpoints, including the Replicated registry, the Replicated proxy registry, the Replicated app service, the Replicated Enterprise Portal, and the Replicated Download Portal.
 
 For information about adding and managing custom domains with the Vendor API v3, see the [customHostnames](https://replicated-vendor-api.readme.io/reference/createcustomhostname) section in the Vendor API v3 documentation.
 
@@ -89,6 +89,16 @@ To configure Embedded Cluster to use your custom domains for the proxy registry
 
 1. Add the Embedded Cluster Config to a new release. Promote the release to a channel that your team uses for testing, and install with Embedded Cluster in a development environment to test your changes.
 
+### Use a Custom Domain for the Replicated SDK Image {#sdk}
+
+The default location for the image used by the Replicated SDK Helm chart is `proxy.replicated.com/library/replicated-sdk-image`. The SDK image is automatically pulled through the Replicated proxy registry during deployment.
+
+You can see the Replicated SDK image properties in the SDK Helm chart [values.yaml](https://github.com/replicatedhq/replicated-sdk/blob/main/chart/values.yaml#L33) file in GitHub.
+
+To use a custom domain for the SDK image:
+
+* Add a custom domain for the Replicated proxy registry. See [Add a Custom Domain in the Vendor Portal](#add-domain) above.
+
 ### Set a Default Domain
 
 Setting a default domain is useful for ensuring that the same domain is used across channels for all your customers.

docs/vendor/custom-domains.md

@@ -14,13 +14,17 @@ You can configure custom domains for the following services:
 
 - **Proxy registry:** Images can be proxied from external private registries using the Replicated proxy registry. By default, the proxy registry uses the domain `proxy.replicated.com`. Replicated recommends using a CNAME such as `proxy.{your app name}.com`. 
 
+     :::note
+     The default location for the image used by the Replicated SDK Helm chart is `proxy.replicated.com/library/replicated-sdk-image`. When you configure a custom domain for the Replicated proxy registry, the SDK is pulled from that custom domain. For more information about the Replicated SDK, see [About the Replicated SDK](/vendor/replicated-sdk-overview).
+     :::
+
 - **Replicated app service:** Upstream application YAML and metadata, including a license ID, are pulled from the app service. By default, this service uses the domain `replicated.app`. Replicated recommends using a CNAME such as `updates.{your app name}.com`. 
 
 - **Enterprise Portal:** The Enterprise Portal is a web-based portal that provides end customers with a centralized location for managing their installation. By default, the Enterprise Portal uses the domain **`[DOMAIN].replicated.com`**. Replicated recommending using a CNAME such as `portal.{your app name}.com` or `enterprise.{your app name}.com`.
 
 - **Download Portal:** The Download Portal can be used to share customer license files, air gap bundles, and so on. By default, the Download Portal uses the domain `get.replicated.com`. Replicated recommends using a CNAME such as `portal.{your app name}.com` or `enterprise.{your app name}.com`. 
 
-- **Replicated registry:** Images and Helm charts can be pulled from the Replicated registry. By default, this registry uses the domain `registry.replicated.com`. Replicated recommends using a CNAME such as `registry.{your app name}.com`.
+- **Replicated registry:** Images and Helm charts can be pulled from the Replicated registry. By default, the Replicated registry uses the domain `registry.replicated.com`. Replicated recommends using a CNAME such as `registry.{your app name}.com`.
 
 ## Limitations
 

docs/vendor/helm-image-registry.mdx

@@ -9,7 +9,9 @@ This topic describes how to use the Replicated proxy registry to proxy images fo
 
 With the Replicated proxy registry, each customer's unique license can grant proxy access to images in an external private registry.
 
-During Helm installations, after customers provide their license ID, a `global.replicated.dockerconfigjson` field that contains a base64 encoded Docker configuration file is automatically injected in the Helm chart values. You can use this `global.replicated.dockerconfigjson` field to create the pull secret required to authenticate with the proxy registry.
+During Helm installations, after customers provide their license ID, a `global.replicated.dockerconfigjson` field that contains a base64 encoded Docker configuration file is automatically injected in the Helm chart values. You can use this `global.replicated.dockerconfigjson` field to create the pull secret required to authenticate with the proxy registry, allowing you to use the proxy registry for images in your Helm charts.
+
+Additionally, if you include the Replicated SDK as a dependency in your Helm chart, the image used by the Replicated SDK is automatically proxied through the proxy registry.
 
 ## Pull Private Images Through the Proxy Registry in Helm Installations
 

docs/vendor/replicated-sdk-customizing.md

@@ -1,8 +1,8 @@
 # Customize the Replicated SDK
 
-This topic describes various ways to customize the Replicated SDK, including customizing RBAC, setting environment variables, adding tolerations, and more.
+This topic describes various ways to customize the Replicated SDK, including customizing RBAC, setting environment variables, adding tolerations, and more. For a complete list of supported configuration options for the SDK, see the [`values.yaml`](https://github.com/replicatedhq/replicated-sdk/blob/main/chart/values.yaml) file for the SDK Helm chart in GitHub.
 
-For a complete list of supported configuration options for the SDK, see the [`values.yaml`](https://github.com/replicatedhq/replicated-sdk/blob/main/chart/values.yaml) file for the SDK Helm chart in GitHub.
+For information about how to use a custom domain for the Replicated SDK image, see [Use a Custom Domain for the Replicated SDK Image](custom-domains-using#sdk) in _Using Custom Domains_.
 
 ## Customize RBAC for the SDK