Configure managed identities for Azure resources on a virtual machine scale set using Azure CLI

Managed identities for Azure resources is a feature of Azure Active Directory. Each of the Azure services that support managed identities for Azure resources are subject to their own timeline. Make sure you review the availability status of managed identities for your resource and known issues before you begin.

Managed identities for Azure resources provide Azure services with an automatically managed identity in Azure Active Directory. You can use this identity to authenticate to any service that supports Azure AD authentication, without having credentials in your code.

In this article, you learn how to perform the following managed identities for Azure resources operations on an Azure virtual machine scale set, using the Azure CLI:

  • Enable and disable the system-assigned managed identity on an Azure virtual machine scale set
  • Add and remove a user-assigned managed identity on an Azure virtual machine scale set

If you don't already have an Azure account, sign up for a free account before continuing.

Prerequisites

  • If you're unfamiliar with managed identities for Azure resources, see What are managed identities for Azure resources?. To learn about system-assigned and user-assigned managed identity types, see Managed identity types.

  • To perform the management operations in this article, your account needs the following Azure role-based access control assignments:

    Note

    No additional Azure AD directory role assignments required.

  • Use the Bash environment in Azure Cloud Shell.

    Launch Cloud Shell in a new window

  • If you prefer, install the Azure CLI to run CLI reference commands.

    • If you're using a local installation, sign in to the Azure CLI by using the az login command. To finish the authentication process, follow the steps displayed in your terminal. For additional sign-in options, see Sign in with the Azure CLI.

    • When you're prompted, install Azure CLI extensions on first use. For more information about extensions, see Use extensions with the Azure CLI.

    • Run az version to find the version and dependent libraries that are installed. To upgrade to the latest version, run az upgrade.

System-assigned managed identity

In this section, you learn how to enable and disable the system-assigned managed identity for an Azure virtual machine scale set using Azure CLI.

Enable system-assigned managed identity during creation of an Azure virtual machine scale set

To create a virtual machine scale set with the system-assigned managed identity enabled:

  1. Create a resource group for containment and deployment of your virtual machine scale set and its related resources, using az group create. You can skip this step if you already have a resource group you would like to use instead:

    az group create --name myResourceGroup --location westus
    
  2. Create a virtual machine scale set. The following example creates a virtual machine scale set named myVMSS with a system-assigned managed identity, as requested by the --assign-identity parameter. The --admin-username and --admin-password parameters specify the administrative user name and password account for virtual machine sign-in. Update these values as appropriate for your environment:

    az vmss create --resource-group myResourceGroup --name myVMSS --image win2016datacenter --upgrade-policy-mode automatic --custom-data cloud-init.txt --admin-username azureuser --admin-password myPassword12 --assign-identity --generate-ssh-keys
    

Enable system-assigned managed identity on an existing Azure virtual machine scale set

If you need to Enable the system-assigned managed identity on an existing Azure virtual machine scale set:

az vmss identity assign -g myResourceGroup -n myVMSS

Disable system-assigned managed identity from an Azure virtual machine scale set

If you have a virtual machine scale set that no longer needs the system-assigned managed identity, but still needs user-assigned managed identities, use the following command:

az vmss update -n myVM -g myResourceGroup --set identity.type='UserAssigned' 

If you have a virtual machine that no longer needs system-assigned managed identity and it has no user-assigned managed identities, use the following command:

Note

The value none is case sensitive. It must be lowercase.

az vmss update -n myVM -g myResourceGroup --set identity.type="none"

User-assigned managed identity

In this section, you learn how to enable and remove a user-assigned managed identity using Azure CLI.

Assign a user-assigned managed identity during the creation of a virtual machine scale set

This section walks you through creation of a virtual machine scale set and assignment of a user-assigned managed identity to the virtual machine scale set. If you already have a virtual machine scale set you want to use, skip this section and proceed to the next.

  1. You can skip this step if you already have a resource group you would like to use. Create a resource group for containment and deployment of your user-assigned managed identity, using az group create. Be sure to replace the <RESOURCE GROUP> and <LOCATION> parameter values with your own values. :

    az group create --name <RESOURCE GROUP> --location <LOCATION>
    
  2. Create a user-assigned managed identity using az identity create. The -g parameter specifies the resource group where the user-assigned managed identity is created, and the -n parameter specifies its name. Be sure to replace the <RESOURCE GROUP> and <USER ASSIGNED IDENTITY NAME> parameter values with your own values:

    Important

    When creating user assigned identities, only alphanumeric characters (0-9, a-z, A-Z), the underscore (_) and the hyphen (-) are supported. Additionally, the name should be atleast 3 characters and up to 128 characters in length for the assignment to VM/VMSS to work properly. Check back for updates. For more information, see FAQs and known issues.

    az identity create -g <RESOURCE GROUP> -n <USER ASSIGNED IDENTITY NAME>
    

    The response contains details for the user-assigned managed identity created, similar to the following. The resource id value assigned to the user-assigned managed identity is used in the following step.

    {
         "clientId": "73444643-8088-4d70-9532-c3a0fdc190fz",
         "clientSecretUrl": "https://control-westcentralus.identity.azure.net/subscriptions/<SUBSCRIPTON ID>/resourcegroups/<RESOURCE GROUP>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/<USER ASSIGNED IDENTITY NAME>/credentials?tid=5678&oid=9012&aid=73444643-8088-4d70-9532-c3a0fdc190fz",
         "id": "/subscriptions/<SUBSCRIPTON ID>/resourcegroups/<RESOURCE GROUP>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/<USER ASSIGNED IDENTITY NAME>",
         "location": "westcentralus",
         "name": "<USER ASSIGNED IDENTITY NAME>",
         "principalId": "e5fdfdc1-ed84-4d48-8551-fe9fb9dedfll",
         "resourceGroup": "<RESOURCE GROUP>",
         "tags": {},
         "tenantId": "733a8f0e-ec41-4e69-8ad8-971fc4b533bl",
         "type": "Microsoft.ManagedIdentity/userAssignedIdentities"    
    }
    
  3. Create a virtual machine scale set. The following example creates a virtual machine scale set associated with the new user-assigned managed identity, as specified by the --assign-identity parameter. Be sure to replace the <RESOURCE GROUP>, <VMSS NAME>, <USER NAME>, <PASSWORD>, and <USER ASSIGNED IDENTITY> parameter values with your own values.

    az vmss create --resource-group <RESOURCE GROUP> --name <VMSS NAME> --image UbuntuLTS --admin-username <USER NAME> --admin-password <PASSWORD> --assign-identity <USER ASSIGNED IDENTITY>
    

Assign a user-assigned managed identity to an existing virtual machine scale set

  1. Create a user-assigned managed identity using az identity create. The -g parameter specifies the resource group where the user-assigned managed identity is created, and the -n parameter specifies its name. Be sure to replace the <RESOURCE GROUP> and <USER ASSIGNED IDENTITY NAME> parameter values with your own values:

    az identity create -g <RESOURCE GROUP> -n <USER ASSIGNED IDENTITY NAME>
    

    The response contains details for the user-assigned managed identity created, similar to the following.

    {
         "clientId": "73444643-8088-4d70-9532-c3a0fdc190fz",
         "clientSecretUrl": "https://control-westcentralus.identity.azure.net/subscriptions/<SUBSCRIPTON ID>/resourcegroups/<RESOURCE GROUP>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/<USER ASSIGNED IDENTITY >/credentials?tid=5678&oid=9012&aid=73444643-8088-4d70-9532-c3a0fdc190fz",
         "id": "/subscriptions/<SUBSCRIPTON ID>/resourcegroups/<RESOURCE GROUP>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/<USER ASSIGNED IDENTITY>",
         "location": "westcentralus",
         "name": "<USER ASSIGNED IDENTITY>",
         "principalId": "e5fdfdc1-ed84-4d48-8551-fe9fb9dedfll",
         "resourceGroup": "<RESOURCE GROUP>",
         "tags": {},
         "tenantId": "733a8f0e-ec41-4e69-8ad8-971fc4b533bl",
         "type": "Microsoft.ManagedIdentity/userAssignedIdentities"    
    }
    
  2. Assign the user-assigned managed identity to your virtual machine scale set. Be sure to replace the <RESOURCE GROUP> and <VIRTUAL MACHINE SCALE SET NAME> parameter values with your own values. The <USER ASSIGNED IDENTITY> is the user-assigned identity's resource name property, as created in the previous step:

    az vmss identity assign -g <RESOURCE GROUP> -n <VIRTUAL MACHINE SCALE SET NAME> --identities <USER ASSIGNED IDENTITY>
    

Remove a user-assigned managed identity from an Azure virtual machine scale set

To remove a user-assigned managed identity from a virtual machine scale set use az vmss identity remove. If this is the only user-assigned managed identity assigned to the virtual machine scale set, UserAssigned will be removed from the identity type value. Be sure to replace the <RESOURCE GROUP> and <VIRTUAL MACHINE SCALE SET NAME> parameter values with your own values. The <USER ASSIGNED IDENTITY> will be the user-assigned managed identity's name property, which can be found in the identity section of the virtual machine scale set using az vmss identity show:

az vmss identity remove -g <RESOURCE GROUP> -n <VIRTUAL MACHINE SCALE SET NAME> --identities <USER ASSIGNED IDENTITY>

If your virtual machine scale set does not have a system-assigned managed identity and you want to remove all user-assigned managed identities from it, use the following command:

Note

The value none is case sensitive. It must be lowercase.

az vmss update -n myVMSS -g myResourceGroup --set identity.type="none" identity.userAssignedIdentities=null

If your virtual machine scale set has both system-assigned and user-assigned managed identities, you can remove all the user-assigned identities by switching to use only system-assigned managed identity. Use the following command:

az vmss update -n myVMSS -g myResourceGroup --set identity.type='SystemAssigned' identity.userAssignedIdentities=null 

Next steps