Tackling Azure Local Automatic Update Issues Triggered by SBE Updates

    Microsoft Azure Local empowers organizations to manage hybrid and edge environments with seamless update capabilities. However, a specific issue with Solution Builder Extension (SBE) updates can cause unexpected automatic OS updates on the third Tuesday of each month, potentially disrupting operations. This blog post, based on detailed technical guidance from Microsoft’s Azure Local documentation and community insights, explains the issue, how to validate its impact, and the steps to mitigate it effectively.

The Issue: Unintended Automatic Updates

For certain server hardware models, monthly cumulative OS updates may install automatically at 3 AM on the third Tuesday of the month if the most recent update included an SBE update. This behavior stems from the Cluster-Aware Updating (CAU) feature, which uses the Microsoft.WindowsUpdatePlugin to deploy updates. If an SBE update configures a scheduled CAU trigger, it can lead to:

• Unplanned downtime due to unexpected system restarts.

• Version misalignment between the Azure Local solution and the OS build, potentially causing compatibility issues (e.g., with .NET versions).

Without intervention, these updates may recur monthly, posing risks to system stability and compliance.

Validating the Issue

To determine if your Azure Local cluster is affected or at risk, perform the following checks as the deployment user on any cluster node.

1. Confirming Unexpected Updates

Use the following PowerShell script to check if a CAU run with the Microsoft.WindowsUpdatePlugin triggered on the third Tuesday:

$getCauReportBlock = {
    [array]$allReports = Get-CauReport -Detailed
    $results = @()
    foreach ($report in $allReports) {
        $summaryReport = @{}
        $summaryReport.RunId = $report.ClusterResult.RunId.Guid
        $summaryReport.StartTimestamp = $report.ClusterResult.StartTimestamp
        $summaryReport.Plugin = $report.Plugin  
        $results += $summaryReport
    }
    return ($results | ?{$_.Plugin -like "*Microsoft.WindowsUpdatePlugin*"})
}
Invoke-Command -Credential $null -Authentication Credssp -Computername localhost -ScriptBlock $getCauReportBlock

If the output confirms a CAU run on the third Tuesday, your cluster has been impacted by this issue.

2. Checking Risk of Future Updates

To assess if your cluster is vulnerable to future automatic updates, run:

Get-CauClusterRole

Check the output for:

• A PreUpdateScript path containing SBECache, indicating an SBE update.

• DaysOfWeek set to Tuesday (value 4) and WeeksOfMonth set to the third week.

If these conditions are met, your cluster is at risk of automatic updates on the next third Tuesday.

Mitigation Steps

To prevent further automatic updates and restore alignment between your Azure Local solution and OS versions, follow these two steps:

Step 1: Remove the Scheduled CAU Trigger

Execute the following PowerShell script to remove the CAU trigger, ensuring no update is in progress and a scheduled trigger exists:

$entry = Get-CauClusterRole -ErrorAction SilentlyContinue | where-object { $_.Name -eq "DaysOfWeek" }  
if ($null -ne $entry -and $entry.Value -eq "4") {
     Write-host "CauClusterRole is scheduled to trigger on 3rd Tuesday!"
     $updateId = (Get-SolutionUpdate | ?{$_.State -like "*ing"}).ResourceId
     if ($null -ne $updateId) {
         throw "Unable to remove scheduled CAU trigger - an update is in progress:`n$($updateId)"
     }
     Remove-CauClusterRole -Force -ErrorAction SilentlyContinue 3>$null 4>$null
     $entry = Get-CauClusterRole -ErrorAction SilentlyContinue | where-object { $_.Name -eq "DaysOfWeek" }
     if ($null -ne $entry -and $entry.Value -eq "4") {
         throw "Attempt to call 'Remove-CauClusterRole' failed.  Assure you are logged in as the deployment user."
     }
     else {
         Write-Host "Confirmed removal of scheduled CAU run!"
     }
}
else {
     Write-Host "CauClusterRole already removed or not scheduled to trigger automatically"
}

This script verifies the third Tuesday trigger, checks for active updates, and safely removes the CAU role. Critical Note: You must repeat this step after each SBE update until your Azure Local solution reaches version 11.2505.x or newer, as earlier versions may reintroduce the trigger.

Step 2: Align Azure Local and OS Versions

If automatic updates have already occurred, your cluster’s OS build may be newer than the expected Azure Local solution version, leading to potential issues (e.g., .NET version mismatches). To resolve this:

• Update your cluster to the Azure Local solution version that matches your current OS build. Refer to the Azure Local release information to identify the appropriate version.

• If the OS build includes a newer .NET version, follow the Azure Local supportability guide for .NET updates when installing solution updates until you reach version 10.2411.1.x or higher.

Perform these updates promptly to restore compatibility and prevent further disruptions.

Why This Matters

Uncontrolled automatic updates can cause significant operational challenges, including:

• Downtime: Unexpected restarts during business hours.

• Compatibility Issues: Mismatched OS and solution versions, especially with .NET dependencies.

• Compliance Risks: Unplanned updates may violate change management policies.

The GitHub reference emphasizes the urgency of addressing this issue before the next third Tuesday to avoid recurring problems. Proactively applying the mitigation steps ensures your Azure Local environment remains stable and secure.

Additional Considerations

• Test in a Staging Environment: Before applying updates in production, test them in a non-critical environment to identify potential conflicts.

• Monitor Regularly: Use the Update Management Center in Azure to track patch status and ensure compliance.

• Stay Informed: Check the Azure Local Supportability repository and Microsoft Learn for updates on this issue and related fixes.

Conclusion

The Azure Local automatic update issue triggered by SBE updates is a critical concern for hybrid cluster management. By validating whether your cluster is affected using the provided PowerShell scripts and applying the two-step mitigation process, you can prevent unexpected updates and maintain version alignment. Act swiftly—especially before the next third Tuesday—and leverage Microsoft’s official resources for ongoing support.

For further details, consult the Azure Local release notes and the Azure Local Supportability repository. Keep your Azure Local environment robust and reliable!

Disclaimer: This post is based on technical documentation from Microsoft and community insights. Always refer to official Microsoft resources for the latest guidance. reference: AzureLocal-Supportability/TSG/Update/OS-update-automatically-set-to-run-on-3rd-Tuesday-following-SBE-update.md at main · Azure/AzureLocal-Supportability · GitHub