While building some multithreading Azure Runbooks that log into multiple subscriptions simultaneously, I noticed that these multiple concurrent runs often end up on the same Azure Automation Host.

Apparently, these runbooks then don’t run in full isolation, and the following error may occur:

The running command stopped because the preference variable “ErrorActionPreference” or common parameter is set to Stop: The process cannot access the file ‘C:\Windows\system32\config\systemprofile\AppData\Roaming\Windows Azure Powershell\TokenCache.dat’ because it is being used by another process.

AzureProfile.json may also get locked. I resolved this by doing a retry on the Save-AzureRMContext, and using a randomized file name for the azure json profile:

$randomProfileName = [System.IO.Path]::GetRandomFileName()

Save-AzureRmContext -Path .\$randomProfileName -Force -Confirm:$False

And for my full Azure Login code snippet:

$randomProfileName = [System.IO.Path]::GetRandomFileName()
 $tries=0
    while($true){
        $tries++
        try{
            Write-Output "Logging in to Azure $azureSubscription"
            $res = Login-AzureRmAccount -Credential $azureCreds -SubscriptionId $azureSubscription -TenantId $tenantId -ErrorAction Stop
            Select-AzureRmSubscription -SubscriptionId $azureSubscription -ErrorAction Stop -TenantId $tenantId
            if($res.Context.Subscription.Id -eq $azureSubscription){
                Write-Output "Logged in to Azure subscription $($res.Context.Subscription.Id)"
            }else{
                Throw "Failed, we were logged in to $($res.Context.Subscription.Id) while trying to log in to $azureSubscription"
            }
            Save-AzureRmContext -Path .\$randomProfileName -Force -Confirm:$False
            break
        }catch{
            if($tries -ge 30){
                Throw
                Exit
            }
            #sleep on failed attempts, as the azure token cache gets locked by concurrent jobs
            sleep -s (Get-Random -minimum 1 -maximum 6)
        }
    }