Document Details

  ################# Input parameters #################
# Resource Group Name where the ExR GWs resides in
$rgList= @('ASH-Cust10-02','ASH-Cust30')  
$thresholdNumRoutes = 160
###################################################

# Ensures you do not inherit an AzContext in your runbook
Disable-AzContextAutosave -Scope Process | Out-Null

Try {

   $conn = Get-AutomationConnection -Name 'AzureRunAsConnection'
   while(!($connectionResult) -And ($logonAttempt -le 5))
   {
        $LogonAttempt++
        # Logging in to Azure...
        $connectionResult =  Connect-AzAccount `
                               -ServicePrincipal `
                               -ApplicationId $conn.ApplicationId `
                               -Tenant $conn.TenantId `
                               -CertificateThumbprint $conn.CertificateThumbprint `
                               -Subscription $conn.SubscriptionId `
                               -Environment AzureCloud 
                               
        Start-Sleep -Seconds 10
    }
} Catch {
    if (!$conn)
    {
        $ErrorMessage = "Service principal not found."
        throw $ErrorMessage
    } 
    else
    {
        Write-Error -Message $_.Exception
        throw $_.Exception
    }
}

# Get the name of the Azure subscription
$subscriptionName=(Get-AzSubscription -SubscriptionId $conn.SubscriptionId).Name

#write-Output "<br>$(Get-Date) - selection of the Azure subscription: $subscriptionName" 
Select-AzSubscription -SubscriptionId $conn.SubscriptionId | Out-Null


$GtwList = @()
$results= @()

foreach ($rgName in $rgList)
{
## Collect all the ExpressRoute gateways in a Resource Group
$GtwList=Get-AzVirtualNetworkGateway -ResourceGroupName $rgName 

## For each ExpressRoute gateway, get the IP addresses of the BGP peers and collect the number of routes advertised 
foreach ($gw in $GtwList) {
  
  $peers = Get-AzVirtualNetworkGatewayBGPPeerStatus -VirtualNetworkGatewayName $gw.Name -ResourceGroupName $rgName


 if ($peers[0].State -eq 'Connected') {
   $routes1=$null
   $routes1 = Get-AzVirtualNetworkGatewayAdvertisedRoute -VirtualNetworkGatewayName $gw.Name -ResourceGroupName $rgName -Peer $peers[0].Neighbor
 }
  if ($peers[1].State -eq 'Connected') {
  
   $routes2=$null
   $routes2 = Get-AzVirtualNetworkGatewayAdvertisedRoute -VirtualNetworkGatewayName $gw.Name -ResourceGroupName $rgName -Peer $peers[1].Neighbor
 }
 
  $sampleTime=(Get-Date).ToString("dd-MM-yyyy HH:mm:ss")
  if ($routes1.Count -eq $routes2.Count)
  {
     
     if ($routes1.Count -lt $thresholdNumRoutes){
       $status='OK'
       $alertMsg='number of routes below threshold'
     } 
     else {
       $status='ALERT'
       $alertMsg='number of routes above threshold'
     }
  } 
  else
  {
     $status='WARNING'
     $alertMsg='check ER Gateway'
  }
  
  $obj = [psCustomObject]@{
            resourceGroup =$rgName
            nameGtw  = $gw.Name
            peer1 = $peers[0].Neighbor
            peer2 = $peers[1].Neighbor
            numRoutesPeer1=  $routes1.Count
            numRoutesPeer2=  $routes2.Count
            time=$sampleTime
            status=$status
            alertMessage = $alertMsg
        }
  $results += $obj
} ### end foreach gateways in each resource group
} ### end foreach resource group
$jsonResults= ConvertTo-Json $results -Depth 100
Write-Output  $jsonResults