MoveDNSToNewPublicIPController.ps1

<#
.SYNOPSIS
This script migrates DNS settings from an old Azure Public IP to a new Azure Public IP and cleans up old resources.

.DESCRIPTION
The script performs several operations in Azure:
1. It prompts the user for confirmation before proceeding, due to potential brief connectivity downtime.
2. Retrieves the DNS settings (Domain Name Label and FQDN) from the old Public IP.
3. Applies these DNS settings to the new Public IP.
4. Removes the old Load Balancer and Public IP after confirming with the user.
The script uses the Az PowerShell module and requires the user to have appropriate permissions to manage resources in Azure.

.PARAMETERS
- subscriptionName: The name of the Azure subscription.
- oldLoadBalancerName: The name of the old Load Balancer to remove.
- resourceGroupName: The name of the Azure resource group containing the resources.
- oldPublicIpName: The name of the old Public IP address to migrate from.
- newPublicIpName: The name of the new Public IP address to migrate to.

.PREREQUISITES
- Az PowerShell module installed.
- User must be logged in to Azure with sufficient permissions to manage the specified resources.

.EXAMPLE
.\MigrateAzureDNS.ps1 -subscriptionName "MySubscription" -oldLoadBalancerName "OldLoadBalancer" -resourceGroupName "MyResourceGroup" -oldPublicIpName "OldPublicIP" -newPublicIpName "NewPublicIP"

.NOTES
Author: Romiko Derbynew
Date: 16-02-2024
#>

param (
    [Parameter(Mandatory = $true)]
    [string]$subscriptionName,

    [Parameter(Mandatory = $true)]
    [string]$oldLoadBalancerName,

    [Parameter(Mandatory = $true)]
    [string]$resourceGroupName,

    [Parameter(Mandatory = $true)]
    [string]$oldPublicIpName,

    [Parameter(Mandatory = $true)]
    [string]$newPublicIpName
)

# Check if Az.Network module is installed; install and import if necessary
if (-not (Get-Module -ListAvailable -Name Az.Network)) {
    Install-Module Az.Network -Force
}
Import-Module Az.Network -Force

$ErrorActionPreference = "Stop"
Connect-AzAccount -Subscription $subscriptionName

Write-Host "WARNING: This operation may cause brief connectivity downtime. Do you want to continue? (Y/N)"
$confirmation = Read-Host
if ($confirmation -ne 'Y') {
    Write-Host "Operation cancelled by the user."
    exit
}

try {
    $oldPrimaryPublicIP = Get-AzPublicIpAddress -Name $oldPublicIpName -ResourceGroupName $resourceGroupName
    $primaryDNSName = $oldPrimaryPublicIP.DnsSettings.DomainNameLabel
    $primaryDNSFqdn = $oldPrimaryPublicIP.DnsSettings.Fqdn
    
    if (![string]::IsNullOrEmpty($primaryDNSName) -and ![string]::IsNullOrEmpty($primaryDNSFqdn)) {
        Write-Host "Found the Primary DNS Name: $primaryDNSName"
        Write-Host "Found the Primary DNS FQDN: $primaryDNSFqdn"
    } else {
        Write-Error "DNS settings not found for Old IP: $oldPublicIpName"
        exit
    }
    
    Write-Host "Moving Azure DNS Names to the new Public IP"
    $newPublicIP = Get-AzPublicIpAddress -Name $newPublicIpName -ResourceGroupName $resourceGroupName
    $newPublicIP.DnsSettings.DomainNameLabel = $primaryDNSName
    $newPublicIP.DnsSettings.Fqdn = $primaryDNSFqdn
    Set-AzPublicIpAddress -PublicIpAddress $newPublicIP

    Write-Host "DNS transfer to new Public IP completed."

    Write-Host "Removing old Load Balancer and Public IP. Are you sure? (Y/N)"
    $confirmation = Read-Host
    if ($confirmation -ne 'Y') {
        Write-Host "Operation cancelled by the user."
        exit
    }

    Remove-AzLoadBalancer -Name $oldLoadBalancerName -ResourceGroupName $resourceGroupName -Force
    Remove-AzPublicIpAddress -Name $oldPublicIpName -ResourceGroupName $resourceGroupName -Force

    Write-Host "Cleanup of old resources completed."
} catch {
    Write-Error "An error occurred: $_"
}