Assign a Managed Service Identity (MSI) access to a resource using Azure CLI

Managed Service Identity (MSI) is a public preview feature of Azure Active Directory. Make sure you review the known issues before you begin. For more information about previews, see Supplemental Terms of Use for Microsoft Azure Previews.

Once you've configured an Azure resource with an MSI, you can give the MSI access to another resource, just like any security principal. This example shows you how to give an Azure virtual machine or virtual machine scale set's MSI access to an Azure storage account, using Azure CLI.

Prerequisites

If you're unfamiliar with MSI, check out the Managed Service Identity overview. If you don't already have an Azure account, sign up for a free account before continuing.

To run the CLI script examples, you have three options:

  • Use Azure Cloud Shell from the Azure portal (see next section).
  • Use the embedded Azure Cloud Shell via the "Try It" button, located in the top right corner of each code block.
  • Install the latest version of CLI 2.0 (2.0.13 or later) if you prefer to use a local CLI console.

Open Azure Cloud Shell

Azure Cloud Shell is a free, interactive shell that you can use to run the steps in this article. Common Azure tools are preinstalled and configured in Cloud Shell for you to use with your account. Just select the Copy button to copy the code, paste it in Cloud Shell, and then press Enter to run it. There are a few ways to open Cloud Shell:

Select Try It in the upper-right corner of a code block. Cloud Shell in this article
Open Cloud Shell in your browser. https://shell.azure.com/bash
Select the Cloud Shell button on the menu in the upper-right corner of the Azure portal. Cloud Shell in the portal

Use RBAC to assign the MSI access to another resource

After you've enabled MSI on an Azure resource, such as an Azure virtual machine or Azure virtual machine scale set:

  1. If you're using the Azure CLI in a local console, first sign in to Azure using az login. Use an account that is associated with the Azure subscription under which you would like to deploy the VM or virtual machine scale set:

    az login
    
  2. In this example, we are giving an Azure virtual machine access to a storage account. First we use az resource list to get the service principal for the virtual machine named "myVM":

    spID=$(az resource list -n myVM --query [*].identity.principalId --out tsv)
    

    For an Azure virtual machine scale set, the command is the same except here, you get the service principal for the virtual machine scale set named "DevTestVMSS":

    spID=$(az resource list -n DevTestVMSS --query [*].identity.principalId --out tsv)
    
  3. Once you have the service principal ID, use az role assignment create to give the virtual machine or virtual machine scale set "Reader" access to a storage account called "myStorageAcct":

    az role assignment create --assignee $spID --role 'Reader' --scope /subscriptions/<mySubscriptionID>/resourceGroups/<myResourceGroup>/providers/Microsoft.Storage/storageAccounts/myStorageAcct
    

Troubleshooting

If the MSI for the resource does not show up in the list of available identities, verify that the MSI has been enabled correctly. In our case, we can go back to the Azure virtual machine or virtual machine scale set in the Azure portal and:

  • Look at the "Configuration" page and ensure MSI enabled = "Yes."
  • Look at the "Extensions" page and ensure the MSI extension deployed successfully (Extensions page is not available for an Azure virtual machine scale set).

If either is incorrect, you may need to redeploy the MSI on your resource again, or troubleshoot the deployment failure.

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