Merge pull request #104749 from dlepow/acifresh2

[ACI] No ACR auth w managed identity

Author: PRMerger18

articles/container-instances/container-instances-using-azure-container-registry.md

@@ -1,16 +1,16 @@
 ---
 title: Deploy container image from Azure Container Registry
-description: Learn how to deploy containers in Azure Container Instances using container images in an Azure container registry.
+description: Learn how to deploy containers in Azure Container Instances by pulling container images from an Azure container registry.
 services: container-instances
 ms.topic: article
-ms.date: 12/30/2019
+ms.date: 02/18/2020
 ms.author: danlep
 ms.custom: mvc
 ---
 
 # Deploy to Azure Container Instances from Azure Container Registry
 
-[Azure Container Registry](../container-registry/container-registry-intro.md) is an Azure-based, managed container registry service used to store private Docker container images. This article describes how to deploy container images stored in an Azure container registry to Azure Container Instances.
+[Azure Container Registry](../container-registry/container-registry-intro.md) is an Azure-based, managed container registry service used to store private Docker container images. This article describes how to pull container images stored in an Azure container registry when deploying to Azure Container Instances. A recommended way to configure registry access is to create an Azure Active Directory service principal and password, and store the login credentials in an Azure key vault.
 
 ## Prerequisites
 
@@ -24,6 +24,9 @@ In a production scenario where you provide access to "headless" services and app
 
 Azure Container Registry provides additional [authentication options](../container-registry/container-registry-authentication.md).
 
+> [!NOTE]
+> You can't authenticate to Azure Container Registry to pull images during container group deployment by using a [managed identity](container-instances-managed-identity.md) configured in the same container group.
+
 In the following section, you create an Azure key vault and a service principal, and store the service principal's credentials in the vault. 
 
 ### Create key vault