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How to setup a VM to boot to last good known configuration (ARM)

  • Article

Symptom:

  • VM stuck in Reboot Loop. Often due to Failed Windows Updates.

Resolution:

1) If Azure PowerShell is not installed, please install it from https://azure.microsoft.com/en-us/downloads/

2) Delete the broken VM. All disks will be kept automatically.

3) Wait for the disk lease to expire. (About 3 mins)

4) Attach the OS disk of the broken VM to a recovery VM located in the same Resource Group and Storage Account.

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5) Change the Source Type to Existing Blog and browse to the broken VHD.

6) Select the broken VHD and continue to attach it to the recovery VM

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7) Once the disk is attached RDP to the recovery VM and ensure that the attached disk is flagged as ONLINE in the Disk Management console.

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8) Before doing any changes create a copy of the folder \windows\system32\config incase rollback is needed

9) On the recovery machine open up regedit

10) Select ‘HKEY_USERS' and select File -> Load Hive

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11) Browse up to the file \windows\system32\config\SYSTEM of the attached affected VMs OS Disk. Most likely this will be Drive E: or F:

12) When opening it will ask for a name, put ‘BROKENSYSTEM’ and select okay

13) Unfold HKEY_USERS and there will be a folder called ‘BROKENSYSTEM’

14) In there, make the following changes:

HKEY_USERS\BROKENSYSTEM\Select\Current                            From 1 to 2
HKEY_USERS\BROKENSYSTEM\Select\Default                             From 1 to 2
HKEY_USERS\BROKENSYSTEM\Select\Failed                               From 0 to 1
HKEY_USERS\BROKENSYSTEM\Select\LastKnownGood          From 2 to 3
HKEY_USERS\BROKENSYSTEM\ControlSet002\Control\CrashControl\Autoreboot         From 1 to 0

15) Select ‘HKEY_LOCAL_MACHINE\BROKENSYSTEM’ then select File -> Unload Hive from the menu

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16) Remove the now fixed disk from the recovery VM in the Azure Portal

17) Wait for the disk lease to expire. (About 3 mins)

18) Recreate the original VM using the following script in PowerShell. All this information can be found by selecting the individual resources in the Portal if you are unsure.

Login-AzureRmAccount
Get-AzureRmSubscription
Get-AzureRmSubscription –SubscriptionID “ SUBID ” | Select-AzureRmSubscription $rgname = "<your RG name>"
$loc = "<your VM location>"
$vmsize = "<your VM size>"
$vmname = "<your VM name>"
$vm = New-AzureRmVMConfig -VMName $vmname -VMSize $vmsize;
$nic = Get-AzureRmNetworkInterface -Name ("YourNICName") -ResourceGroupName $rgname;
$nicId = $nic.Id;
$vm = Add-AzureRmVMNetworkInterface -VM $vm -Id $nicId;
$osDiskName = "YourDiskOSName"
$osDiskVhdUri = "YourDiskOSUri"
$vm = Set-AzureRmVMOSDisk -VM $vm -VhdUri $osDiskVhdUri -name $osDiskName -CreateOption attach -Windows

New-AzureRmVM -ResourceGroupName $rgname -Location $loc -VM $vm -Verbose

Here is an example of what is should look like:

# To login to Azure Resource Manager
Login-AzureRmAccount

# To view all subscriptions for your account
Get-AzureRmSubscription

# To select a default subscription for your current session
Get-AzureRmSubscription –SubscriptionID “12345678 -1234-123r-5332-522214446c32 ” | Select-AzureRmSubscription

$rgname = "server2012r2"
$loc = "southcentralus"
$vmsize = "Standard_A1"
$vmname = "server2012r2"
$vm = New-AzureRmVMConfig -VMName $vmname -VMSize $vmsize;
$nic = Get-AzureRmNetworkInterface -Name ("server2012r2577") -ResourceGroupName $rgname;
$nicId = $nic.Id;
$vm = Add-AzureRmVMNetworkInterface -VM $vm -Id $nicId
$osDiskName = "server2012r2"
$osDiskVhdUri = " https://server2012r23384.blob.core.windows.net/vhds/server20121163546110340.vhd "
$vm = Set-AzureRmVMOSDisk -VM $vm -VhdUri $osDiskVhdUri -name $osDiskName -CreateOption attach -Windows

New-AzureRmVM -ResourceGroupName $rgname -Location $loc -VM $vm -Verbose

 

19) Run the script and head to the portal. Once the VM is finished being created connect via RDP

Comments

  • Anonymous
    May 24, 2017
    Thanks for your post Micah, but it didn't work for me. After editing the registry hive and recreated the VM, it shows a black screen in boot diagnostics with an error saying that winload.exe cannot be found. My failing VM is a domain controller. Any similar method to boot into failsafe mode with RDP? Thanks.
    • Anonymous
      May 24, 2017
      Hey Carlos. What is the error code you are seeing in boot diagnostics? Winload.exe missing can mean a few different things depending on the associated error code