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Azure Automation for IT Pros
I’ve spent a lot of time working with Azure Automation over the last few years. It’s an extremely useful facility for tenant administrators who want to run PowerShell scripts using a more modern mechanism than offered by Windows Scheduler. This is especially true so in large tenants where processing hundreds or thousands of objects is common, which is why I started to use Run As accounts with Azure Automation.
Converting scripts to run on Azure Automation isn’t too difficult, once you understand the headless nature of the beast and that PowerShell runs on virtual machines spun up for the purpose. The biggest issue often faced when moving scripts from running interactively to being an Azure Automation runbook is how to create output from scripts, but it’s possible to send email, post to Teams channels, and create files in SharePoint document libraries.
Microsoft seems to communicate with developers and administrators (aka IT Pros) in different ways. For instance, the news about the retirement of Azure Automation Run As accounts on September 30, 2023, didn’t appear in any notification in the Microsoft 365 admin center. In fact, apart from the notices posted in Azure Automation documentation (like that shown in Figure 1), I can’t find a formal announcement from Microsoft.
Informing the Technical Community About the Run As Retirement
The possibility exists that I might not be looking hard enough. Normally, I am reasonably proficient with search (Google), but the first hit I find is a 27 September 2022 Microsoft Answers post saying “On 30 September 2023, we’ll retire the Azure Automation Run As account that you use for Runbook authentication.” I can find an earlier “plan for change” note for July 2022 in the What’s new in Azure Automation page. Apart from that, Microsoft seems to have updated the documentation on 18 October 2022 (here’s the FAQ).
I suppose that it’s reasonable to expect people to learn about developments from documentation. In this instance, I think Microsoft dropped the ball and didn’t do a great job of telling people what’s going to happen when Run As accounts retire.
Managed Identities Are a Better Solution
The logic for retiring Run As accounts is undeniable. A better and more secure solution (managed identities) exists. Run As accounts authenticate using a self-signed certificate that needs to be renewed yearly. Microsoft has removed the ability to renew these certificates from the Azure portal, meaning that Run As accounts are counting down to a time when they won’t be able to authenticate. Microsoft has a script to renew certificates for Run As accounts and the script will run after September 30, 2023. However, Run As accounts will then be unsupported, which isn’t a great situation for production components.
The nice thing about managed identities from an Office 365 perspective is that the important PowerShell modules used for automation support managed identities. Some do so very smoothly (like the latest Exchange Online management module, where even the latest RBAC for applications feature supports managed identities) and some do it with a little extra work. For example, V1.0 of the Microsoft Graph PowerShell SDK needs to get an access token from the Azure Automation account that owns a managed identity while V2.0 will be able to sign in using a managed identity. Here’s an example of a simple runbook that:
- Connects to the Azure Automation account using a managed identity.
- Gets an access token from Azure AD.
- Uses the access token to connect to the Graph with Connect-MgGraph.
- Retrieves the service domain (like office365itpros.onmicrosoft.com) using the Get-MgOrganization cmdlet.
- Uses the service domain and a managed identity to connect to Exchange Online.
- Lists details of user mailboxes.
# Connect to Microsoft Graph with Azure Automation
Connect-AzAccount -Identity
$AccessToken = Get-AzAccessToken -ResourceUrl "https://graph.microsoft.com"
Connect-MgGraph -AccessToken $AccessToken.Token
# Get Tenant service domain using Get-MgOrganization
$TenantName = (Get-MgOrganization).VerifiedDomains | Where-Object {$_.IsInitial -eq $True} | Select-Object -ExpandProperty Name
# Connect to Exchange Online
Connect-ExchangeOnline -ManagedIdentity -Organization $TenantName
Get-ExoMailbox -RecipientTypeDetails UserMailbox | Format-Table DisplayName, UserPrincipalName
When V2.0 of the Microsoft Graph PowerShell SDK is available, you’ll be able to replace the first three lines of code with a simple Connect-MgGraph -Identity.
Another example of using a managed identity with Exchange Online is to monitor events gathered in the audit log to detect and report events that might indicate potential tenant compromise. Running the script on an Azure Automation schedule makes sure that audit events are checked without human intervention.
Time to Move Forward
Apart from the poor communication, I don’t have any problem with Microsoft’s decision to retire Run As accounts. They worked as a mechanism to connect resources to Azure Automation. We’re just moving on to adopt a new approach. Microsoft documents the migration steps to move from a Run As account to use managed identities. It’s a manual process, but not onerous.