Archive Azure Activity Logs for multiple subscriptions

ActivityLog_EventHubArchiving.ps1

<#
    .SYNOPSIS
        This script will configure EventHub logging for all Azure Activity logs in multiple subscriptions so that you can then archive the logs to another system 
        See: https://docs.microsoft.com/en-us/powershell/module/az.monitor/add-azlogprofile 
    .DESCRIPTION
        Using an AAD account that has access to all of the subscriptions that you need to configure, this will loop through all of those
        subscriptions, find all of the EventHub namespaces in those subscriptions and then find an EventHub that meets a specific naming format.
        Once the proper EventHub is found, it will set the log profile for you

        The naming format of the EventHub is up to you and can be edited on the "if($eventHub.Name ..." line #45
        Alternatively, you could create a string array of EventHub names and look for a match in the loop
#>


#Login to Azure AD with an account that has access to all of the subscriptions that you need to configure
Login-AzAccount

#Pre-set variables 
$logProfileName = "default"
$locations = (Get-AzLocation).Location
$locations += "global"
$sCtx

#Get the list of subscriptions that the login has access to
$subIds = (Get-AzSubscription).Id

#Loop through the subscriptions
foreach($subscriptionId in $subIds)
{

   Write-Output "Subscription ID: $subscriptionId"

   #Change subscription context and confirm the change...
   while($sCtx.Subscription.Id -ne $subscriptionId)
    {
        $sCtx = Set-AzContext -Subscription "$subscriptionId" -Scope Process
    }

   #Get the EventHub namespaces for this subsciption
   $eventHubNamespaces = Get-AzEventHubNamespace 

   #loop through all of the namespaces to find a matching EventHub
   foreach($eventHub in $eventHubNamespaces)
   {
        if($eventHub.Name -match "<edit me!>")  #EDIT THIS LINE to meet your naming match 
        {
            #Set the Log profile to the EventHub
            Write-Output "Found matching EventHub: $($eventHub.Name)"
            $resourceGroupName = $eventHub.ResourceGroup
            $serviceBusRuleId = "/subscriptions/$subscriptionId/resourceGroups/$resourceGroupName/providers/Microsoft.EventHub/namespaces/$($eventHub.Name)/authorizationrules/RootManageSharedAccessKey"
            Add-AzLogProfile -Name $logProfileName -Location $locations -ServiceBusRuleId $serviceBusRuleId
        }
   }
}