Creating user managed identity considering secure and automatic

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Creating user managed identity considering secure and automatic

Varma 1,495

Creating user managed identity

I need to use this user managed identity for the virtual machine which gets created in the backend and gets deleted after process is over when we run packer build command.

https://learn.microsoft.com/en-us/entra/identity/managed-identities-azure-resources/how-to-use-vm-token#get-a-token-using-powershell

Please suggest how we can create user managed identity consider secure and automatic

I was going through above link but not sure which one to pick and how to use

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Answer 1

RevelinoB 3,675

Hi Varma,

When reading your query, creating and using a User Managed Identity (UMI) in Azure for a scenario like yours, where a virtual machine (VM) is dynamically created and deleted as part of a process (e.g., via Packer), involves several steps. The goal is to ensure that the process is both secure and automated. Managed identities for Azure resources provide an Azure Active Directory identity that your application can use to connect to resources that support Azure AD authentication, without needing credentials in your code.

Here's how you can proceed, based on the information you've found and your requirements:

Create a User Managed Identity

First, you'll need to create a User Managed Identity in Azure. This can be done through the Azure portal, Azure CLI, or PowerShell. Given that you're looking for an automated approach, here's how to do it via Azure CLI:

az identity create --resource-group <ResourceGroupName> --name <IdentityName>

Replace <ResourceGroupName> with the name of your Azure resource group, and <IdentityName> with a name for your new identity.

Assign the Identity to the VM

When you're creating a VM with Packer, you can assign the managed identity to the VM. If you're using an Azure Resource Manager (ARM) template with Packer, you can specify the identity under the identity property of the VM resource. Here's an example snippet:

"identity": {

"type": "UserAssigned",

"userAssignedIdentities": {

"/subscriptions/<SubscriptionId>/resourcegroups/<ResourceGroupName>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/<IdentityName>": {}

}

Make sure to replace <SubscriptionId>, <ResourceGroupName>, and <IdentityName> with your actual subscription ID, resource group name, and the name of the managed identity, respectively.

Use the Managed Identity to Access Resources

Once the VM is assigned a managed identity, applications running on the VM can use this identity to access Azure resources that support Azure AD authentication, without needing to manage credentials. To obtain an access token for the managed identity, you can use the following command on the VM:

$response = Invoke-RestMethod -Method 'GET' -Headers @{Metadata="true"} -Uri 'http://169.254.169.254/metadata/identity/oauth2/token?api-version=2018-02-01&resource=https://management.azure.com/'

$accessToken = $response.access_token

This token can then be used to authenticate API calls to Azure services.

Automate and Secure the Process

Automation: Ensure that the process of creating the identity, assigning it to a VM, and using it within your application is automated as part of your CI/CD pipeline. This can be achieved by scripting these steps using Azure CLI or PowerShell scripts.
Security: Always follow the principle of least privilege by assigning only the necessary permissions to the managed identity. You can control these permissions through Azure role-based access control (RBAC) by assigning appropriate roles to the managed identity.

Clean-up

Since your VMs are ephemeral, you might also want to automate the clean-up process. This includes removing the managed identity from the VM before deletion and, if the identity is no longer needed, deleting the managed identity itself. This can be scripted as part of your process to ensure resources are not left unused.

By following these steps, you should be able to securely and automatically use a User Managed Identity with your VMs in Azure, leveraging the managed identity for authentication without embedding credentials in your code or configuration.

I hope this help with your query. If you have any questions please let me know.

Varma 1,495 Reputation points

2024-03-03T06:42:03.9266667+00:00

Hi Revelino B,

I have created the identity using the command you have given in CG resource group

But i have not found that identity in CG resource group, please see below

ad my second question:

I need to give my user managed identity details in the below template ex:

https://developer.hashicorp.com/packer/integrations/hashicorp/azure/latest/components/builder/arm

i the below highlighted line i need to give user managed identity details, how to give

please assist o this , thank you
RevelinoB 3,675 Reputation points

2024-03-03T06:51:46.2266667+00:00
Hi Varma,

For your first question, concerning the visibility of the created identity in the resource group, here are the steps you can take:

Confirm the Identity Creation: Ensure that the identity has been created successfully by checking the output of the command you ran. The JSON output should provide an id field with the resource identifier for the identity.

Check in the Correct Scope: Managed identities are not displayed alongside other resources like VMs or storage accounts. They are typically listed under the "Managed Identities" section within the Azure portal. Make sure you are looking in the right place within the Azure portal.

Refresh the Azure Portal: Sometimes, the Azure portal UI might not immediately reflect new resources due to caching. Try refreshing the portal or re-navigating to the resource group.

Check with Azure CLI or PowerShell: To confirm the existence of the managed identity, you can list all managed identities within the resource group using the Azure CLI or PowerShell.

For Azure CLI, the command is:

az identity list --resource-group <ResourceGroupName>

For the second question, regarding how to specify the user managed identity in the Packer template, you need to use the resource ID of the managed identity you created. It looks like you've already retrieved this information as seen in the first attachment.

Here's how you can specify it in the Packer template:

Locate the User Managed Identity Section: Find the section in your Packer template where you can specify user managed identities. It should be within the builder section for Azure.

Specify the Managed Identity ID: Use the user_assigned_managed_identities field to list your managed identity ID(s). The ID should be the full resource ID as given in the id field from the JSON output when you created the identity.

For example:

{

"builders": [

{

"type": "azure-arm",

...

"user_assigned_managed_identities": [

"/subscriptions/{subscription-id}/resourcegroups/{resource-group-name}/providers/Microsoft.ManagedIdentity/userAssignedIdentities/{identity-name}"

],

...

}

]

}

Replace {subscription-id}, {resource-group-name}, and {identity-name} with your actual subscription ID, resource group name, and the name of the managed identity, respectively.

If you're still having trouble finding the managed identity or configuring it in your Packer template, please let me know, and we can delve deeper into troubleshooting the issue

Varma 1,495

HI Revelino B,

Thank you for the response.

I have created as per your command I can see it in the resource group

User's image

and instead of creating can we do it like at storage account level or at blob level? and use it for packer virtual machine?

am I missing something after creating the identity? because I am seeing following error

User's image

azure-arm.autogenerated_1: I:\packers>az storage blob download --account-name sa123 --container-name con123 --file 'C:\software\SampleZIPFile_100mbmb.ZIP' --blob-url 'https://sa123.blob.core.windows.net/con123/SampleZIPFile_100mbmb.zip'
==> azure-arm.autogenerated_1: WARNING:

==> azure-arm.autogenerated_1: There are no credentials provided in your command and environment, we will query for account key for your storage account.

**==> azure-arm.autogenerated_1: It is recommended to provide --connection-string, --account-key or --sas-token in your command as credentials.**

**==> azure-arm.autogenerated_1:**

**==> azure-arm.autogenerated_1: You also can add `--auth-mode login` in your command to use Azure Active Directory (Azure AD) for authorization if your login account is assigned required RBAC roles.**

==> azure-arm.autogenerated_1: For more information about RBAC roles in storage, visit [https://docs.microsoft.com/azure/storage/common/storage-auth-aad-rbac-cli]().

==> azure-arm.autogenerated_1:

==> azure-arm.autogenerated_1: In addition, setting the corresponding environment variables can avoid inputting credentials in your command. Please use --help to get more information about environment variable usage.

==> azure-arm.autogenerated_1: ERROR: The command failed with an unexpected error. Here is the traceback:

==> azure-arm.autogenerated_1: ERROR: Unable to determine account name for shared key credential.

==> azure-arm.autogenerated_1: Traceback (most recent call last):

2nd question:

can we create a user managed identity at the blob level and use it for packer machine?

how we need to add role to that particular identity and what role we need to grant in my case?

RevelinoB 3,675 Reputation points

2024-03-03T09:52:38.33+00:00
Hi Varma,

It looks like you're trying to use the Azure Managed Identity to authenticate and download a blob from an Azure Storage account. Here's how to resolve the issues you're facing:

Assign Role to Managed Identity: After creating a managed identity, you need to assign it appropriate roles. For accessing blobs in a storage account, you can assign the "Storage Blob Data Contributor" role to the managed identity at the storage account level. This will give the identity permission to read and write to the storage account's blobs.

You can assign the role using the Azure portal or Azure CLI. Here's an example Azure CLI command to assign a role to the managed identity:

az role assignment create --assignee <PrincipalId> --role "Storage Blob Data Contributor" --scope /subscriptions/<SubscriptionId>/resourceGroups/<ResourceGroupName>/providers/Microsoft.Storage/storageAccounts/<StorageAccountName>

Replace <PrincipalId>, <SubscriptionId>, <ResourceGroupName>, and <StorageAccountName> with your managed identity's principal ID, your subscription ID, your resource group name, and the storage account name, respectively.

Authenticating with Managed Identity: To use the managed identity for authentication, you need to set the --auth-mode to login in your az storage blob download command if you are running the command from a VM or environment where the managed identity is available. Ensure the Azure CLI is logged in with an account that has the Managed Identity Operator role.

az storage blob download --account-name <StorageAccountName> --container-name <ContainerName> --file <LocalFilePath> --name <BlobName> --auth-mode login

Replace <StorageAccountName>, <ContainerName>, <LocalFilePath>, and <BlobName> with your storage account name, container name, the path to the file on your local machine, and the blob name, respectively.

For the second question, managed identities cannot be created at the blob level. They are created at the Azure service level (like VM, App Service, etc.) and can be assigned roles at various scopes (subscription, resource group, specific resource like a storage account).

Here are the steps to add a role to the particular identity:

Go to the Azure portal.

Navigate to the storage account where your blob is located.

Click on "Access control (IAM)".

Click on "Add role assignment".

Select the role you wish to assign (e.g., "Storage Blob Data Contributor").

Search for your managed identity by name and select it.

Click "Save" to assign the role.

By following these steps, your managed identity should be able to authenticate using Azure AD and perform actions on the blob as allowed by the role assignments. If the error persists, ensure that your Azure CLI session is logged in with an account that has sufficient permissions and that the managed identity has been granted the correct role assignments. Hope this helps with your query.
Varma 1,495 Reputation points

2024-03-03T09:53:58.14+00:00

test123
Varma 1,495 Reputation points

2024-03-03T10:18:58.99+00:00

Hi Revelinno

After added respective role assignment to storage account that error is gone

but now it is giving add az login error in the packer logs.

can we add az login with out asking for prompt in the below template. I know below will give prompt while executing in the packer build

2nd question

since we create managed identity at the resource group level and every body can use that managed identity for accessing some other resources and by adding role, what is the way to fix this? please suggest.

3rd question

do you think using access token, is it needed in my case? if yes please suggest how to fix following error.
Varma 1,495 Reputation points

2024-03-03T12:05:02.1533333+00:00

test123
RevelinoB 3,675 Reputation points

2024-03-03T12:57:43.01+00:00
Hi Varma,

Let's address each of your questions one by one:

Question 1: Non-interactive az login

In your Packer template, you are trying to perform az login which typically requires an interactive login prompt. To avoid this and allow for non-interactive login, you can do the following:

Use a Service Principal with a Client Secret: Create a service principal and use the client ID, tenant ID, and client secret to log in non-interactively.

az login --service-principal -u [Client_ID] -p [Client_Secret] --tenant [Tenant_ID]

Managed Identity: If you are running this on a VM that has a managed identity assigned and the role assignments are correct, you can use managed identity directly without needing to log in.

For your Packer template, if the environment where Packer is running has a managed identity assigned and the correct role assignments, you can remove the az login line.

Question 2: Restricting Managed Identity Usage

Managed identities are tied to specific Azure resources, and their usage is controlled by the Role-Based Access Control (RBAC) you set. To restrict who can use the managed identity:

Assign roles only to specific resources, not at the resource group level if you want to limit access.

Use RBAC to control which users or groups can manage these identities.

Audit access and assignments regularly to ensure they are still appropriate.

Question 3: Access Token Error

The error you are seeing in the second attachment is likely because you are trying to get a token from an environment that does not have a managed identity enabled or you are not running the command from within an Azure resource that has the managed identity assigned.

Here's how to fix the access token issue:

Ensure you are running the command on an Azure resource that has the managed identity assigned.

If you are running the command on a local machine or outside Azure, you cannot use the managed identity token endpoint (http://169.254.169.254/metadata/identity/oauth2/token). This endpoint is only accessible from within an Azure resource that has a managed identity enabled.

If you need to authenticate to Azure from a non-Azure environment, you'll need to use a service principal or other means of authentication that do not rely on managed identities.

To summarize:

For non-interactive login within Packer, consider using a service principal or leveraging the managed identity directly if Packer runs on an Azure VM with an identity assigned.

Control the usage of managed identities by careful role assignment and RBAC policies.

Access tokens from the managed identity endpoint can only be used within the Azure resource that has the identity enabled. Ensure you're running commands from the right environment or use a service principal outside Azure.

Varma 1,495

HI Revelino B,

I tried to created SP and then provided command below. but still it is asking for az login prompt in the packer logs, please see below and please suggest, thank you

User's image

I have given template here, I just given XXX for subscription and other details.

I am just looking for downloading the blob url from packer machine


 packer {
    required_plugins {
      azure = {
        version = ">= 1.0.0"
        source = "github.com/hashicorp/azure"
      }
    }
  }
 
 
source "azure-arm" "autogenerated_1" {
 
  azure_tags = {
 
    Environment = "Development"
 
    Owner = "Shyam"
 
  }
  use_azure_cli_auth = true
  build_resource_group_name         = "packer"
 
 
 
image_publisher =  "MicrosoftWindowsServer"
 
  image_offer = "WindowsServer"
 
  image_sku = "2019-Datacenter"
 
  shared_image_gallery_destination {
 
    subscription = "XXX"
 
    resource_group = "cg"
 
    gallery_name         = "gallery1"
    image_name           = "webserver"
    image_version        = "1.0.72"
 
    replication_regions = ["eastus2"]
 
    storage_account_type = "Standard_LRS"
 
}
 
  os_type                             = "Windows"
 
  subscription_id                     = "XXX"
 
  tenant_id                           = "XXXX"
 
vm_size                             = "Standard_D16lds_v5"
 
  communicator                        = "winrm"
 
  winrm_insecure                      = true
 
  winrm_timeout                       = "60m"
 
  winrm_use_ssl                       = true
 
winrm_username                        = "packer"
 
}
 
build {
 
  sources = ["source.azure-arm.autogenerated_1"]
 
  
  provisioner "powershell" {
    inline = ["New-Item -ItemType Directory -Path 'c:/software'",
      
      "Invoke-RestMethod -uri 'https://aka.ms/installazurecliwindowsx64' -OutFile 'c:/software/azure-cli-2.57.0-x64.msi'",
      "Start-Process msiexec.exe -Wait -ArgumentList '/I c:\\software\\azure-cli-2.57.0-x64.msi /quiet'"
  
    ]
  }
 
   provisioner "powershell" {
    inline = [
  "az login --service-principal -u 4f81ea7c-2b1d-4f79-8573-000cfdd32ac2 -p EJJ8Q~tOLD.ckvIJL9eIcynPwgx_f2ZlxKIyDcJG --tenant 8e0b6750-ef80-4f5b-98b3-fa2b9f690006",
      "az storage blob download --account-name sa123 --container-name con123 --file 'C:\\software\\SampleZIPFile_100mbmb.ZIP' --blob-url 'https://sa123.blob.core.windows.net/con123/SampleZIPFile_100mbmb.zip' --auth-mode login "
    ]
  }
 
  provisioner "powershell" {
 
    inline = ["while ((Get-Service RdAgent).Status -ne 'Running') { Start-Sleep -s 5 }",
 
     "while ((Get-Service WindowsAzureGuestAgent).Status -ne 'Running') { Start-Sleep -s 5 }",
 
     "& $env:SystemRoot\\System32\\Sysprep\\Sysprep.exe /oobe /generalize /quiet /quit",
 
     "while($true) { $imageState = Get-ItemProperty HKLM:\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Setup\\State | Select ImageState; if($imageState.ImageState -ne 'IMAGE_STATE_GENERALIZE_RESEAL_TO_OOBE') { Write-Output $imageState.ImageState; Start-Sleep -s 10  } else { break } }"
     ]
 
  }
 
}

RevelinoB 3,675 Reputation points

2024-03-03T15:57:26.1766667+00:00
Hi Varma,

The issue you're encountering with the az login prompt within the Packer logs, even after using a service principal, suggests that the login command might not be working as expected. There are a few things we can check to resolve this issue:

Check the Service Principal Credentials: Verify that the service principal ID, tenant ID, and secret are correct and have the necessary permissions.

Ensure Non-Interactive Mode: You're using the service principal for non-interactive mode which is correct, but ensure that the environment where Packer is running does not have any interactive prompts enabled. Packer runs PowerShell scripts non-interactively, and any attempt to open a prompt will cause it to hang or fail.

Auth-Mode for az storage blob download: The --auth-mode parameter should not be set to login when using a service principal. It's meant for use with a logged-in user session. Since you're using a service principal, this parameter is not needed. The service principal's permissions will be used directly if it's properly logged in.

Here is a corrected inline provisioner block:

provisioner "powershell" {

inline = [

"az login --service-principal -u <AppID> -p <Password> --tenant <TenantID>",

"az storage blob download --account-name sa123 --container-name con123 --file 'C:\\software\\SampleZIPFile_100mbmb.ZIP' --blob-url 'https://sa123.blob.core.windows.net/con123/SampleZIPFile_100mbmb.zip'"

]

}

Replace <AppID>, <Password>, and <TenantID> with your actual service principal's application (client) ID, password (client secret), and tenant ID.

Check for Environment Variables: If there are any environment variables related to Azure CLI or authentication set in your system, they might interfere with the Packer script execution.

Ensure SP has Access: Make sure the service principal has the "Storage Blob Data Contributor" role assigned to the storage account you're trying to access.

Logging: You can add additional logging to the script to check if az login was successful by checking the exit code $? right after the az login command.

If these steps do not resolve the issue, you might consider using a Managed Identity if Packer is running within an Azure VM that supports Managed Identities. This would remove the need for handling service principal credentials within your template.

Lastly, ensure that your syntax and parameter passing are correct within the Packer template. Any syntax error might cause the script to fail. If you're still encountering issues, you may want to check the Packer documentation or seek support from the Packer community for more specific guidance related to Packer's execution environment.

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Creating user managed identity considering secure and automatic

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