traffic-management-container-instances.ps1

param (
    [string]$resourceGroupName = "bootcamp-rg",
    [string]$trafficManagerProfile = "bootcamp-traffic-manager",
    [string]$tagName = "multi-instance"
)
$servicePrincipalConnection = Get-AutomationConnection -Name "AzureRunAsConnection"
Connect-AzAccount `
    -ServicePrincipal `
    -TenantId $servicePrincipalConnection.TenantId `
    -ApplicationId $servicePrincipalConnection.ApplicationId `
    -CertificateThumbprint $servicePrincipalConnection.CertificateThumbprint
       
$active_routes = New-Object "System.Collections.Generic.List[string]"
$endpoints = Get-AzTrafficManagerProfile $resourceGroupName $trafficManagerProfile
foreach ($profile in $endpoints.Endpoints) {
    $target = $profile.Target
    Write-Output "$target is added to active route table."
    $active_routes.Add($target)
}

$azContainerInstances = (Get-AzContainerGroup $resourceGroupName) | Select-Object Fqdn, Tags
$containerInstances = New-Object "System.Collections.Generic.Dictionary[string,bool]"

foreach ($instance in $azContainerInstances) {
    $fqdn = $instance.Fqdn
    $taggedAsScale = $instance.Tags.ContainsKey($tagName) -and $instance.Tags[$tagName] -eq "true"
    $containerInstances.Add($fqdn, $taggedAsScale)
    Write-Output "'$fqdn' is tagged as '$tagName=$taggedAsScale'"
}

foreach ($fqdn in $containerInstances.Keys) {
    if ($containerInstances[$fqdn] -and !$active_routes.Contains($fqdn)) {
        New-AzTrafficManagerEndpoint `
            -ProfileName $trafficManagerProfile `
            -ResourceGroupName $resourceGroupName `
            -Type ExternalEndpoints `
            -Name $fqdn `
            -Target $fqdn `
            -Weight 1 `
            -EndpointStatus Enabled
        Write-Output "$fqdn is ADDED to traffic manager."
    }  
    elseif (!$containerInstances[$fqdn] -and $active_routes.Contains($fqdn)) {
        Remove-AzTrafficManagerEndpoint `
            -ProfileName $trafficManagerProfile `
            -ResourceGroupName $resourceGroupName `
            -Type ExternalEndpoints `
            -Name $fqdn `
            -Force
        Write-Output "$fqdn is REMOVED from traffic manager."
    }
}