AzureBasicLoadBalancerUpgrade

2.4.14

modules/RemoveBasicLoadBalancer/RemoveBasicLoadBalancer.psm1


# Load Modules
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/Log/Log.psd1")
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/UpdateVmss/UpdateVmss.psd1")
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/UpdateVmssInstances/UpdateVmssInstances.psd1")
Import-Module ((Split-Path $PSScriptRoot -Parent) + "/GetVmssFromBasicLoadBalancer/GetVmssFromBasicLoadBalancer.psd1")

function RemoveBasicLoadBalancer {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory = $True)][Microsoft.Azure.Commands.Network.Models.PSLoadBalancer] $BasicLoadBalancer,
        [Parameter(Mandatory = $true)] $BackendType
    )

    If ($BackendType -eq 'VMSS') {
        log -Message "[RemoveBasicLoadBalancerFromVmss] Initiating removal of LB $($BasicLoadBalancer.Name) from VMSS $($VMSS.Name)"
        log -Message "[RemoveBasicLoadBalancerFromVmss] Looping all VMSS from Basic Load Balancer $($BasicLoadBalancer.Name)"

        log -Message "[RemoveBasicLoadBalancerFromVmss] Building VMSS object from Basic Load Balancer $($BasicLoadBalancer.Name)"
        $vmss = GetVmssFromBasicLoadBalancer -BasicLoadBalancer $BasicLoadBalancer

        log -Message "[RemoveBasicLoadBalancerFromVmss] Checking Upgrade Policy Mode of VMSS $($vmss.Name)"
        if ($vmss.UpgradePolicy.Mode -eq "Rolling") {
            log -Message "[RemoveBasicLoadBalancerFromVmss] Upgrade Policy Mode of VMSS $($vmss.Name) is Rolling"
            log -Message "[RemoveBasicLoadBalancerFromVmss] Setting Upgrade Policy Mode of VMSS $($vmss.Name) to Manual"
            $vmss.UpgradePolicy.Mode = "Manual"
        }

        log -Message "[RemoveBasicLoadBalancerFromVmss] Checking Automatic OS Upgrade policy of VMSS $($vmss.Name)"
        if ($vmss.upgradePolicy.AutomaticOSUpgradePolicy.enableAutomaticOSUpgrade -eq $true) {
            log -Message "[RemoveBasicLoadBalancerFromVmss] Automatic OS Upgrade policy of VMSS $($vmss.Name) is enabled"

            If ($null -ne $vmss.VirtualMachineProfile.NetworkProfile.healthProbe) {
                log -Message "[RemoveBasicLoadBalancerFromVmss] VMSS is using LB-based health probe. EnableAutomaticOSUpgrade cannot be true if neither health probe or application health extension exists and the health probe will be removed during migration, so enableAutomaticOSUpgrade will be set to false and reverted post-migration."
                $vmss.upgradePolicy.AutomaticOSUpgradePolicy.enableAutomaticOSUpgrade = $false
            }
            ElseIf ($vmss.VirtualMachineProfile.ExtensionProfile.Extensions.Type -contains 'ApplicationHealthLinux' -or 
                $vmss.VirtualMachineProfile.ExtensionProfile.Extensions.Type -contains 'ApplicationHealthWindows') {
                log -Message "[RemoveBasicLoadBalancerFromVmss] VMSS is using Application Health Extension, so enableAutomaticOSUpgrade can remain enabled."
            }
        }

        log -Message "[RemoveBasicLoadBalancerFromVmss] Cleaning healthProbe from NetworkProfile of VMSS $($vmss.Name)"
        $vmss.VirtualMachineProfile.NetworkProfile.healthProbe = $null

        log -Message "[RemoveBasicLoadBalancerFromVmss] Cleaning LoadBalancerBackendAddressPools from Basic Load Balancer $($BasicLoadBalancer.Name)"
        foreach ($networkInterfaceConfiguration in $vmss.VirtualMachineProfile.NetworkProfile.NetworkInterfaceConfigurations) {
            foreach ($ipConfiguration in $networkInterfaceConfiguration.IpConfigurations) {
                $ipConfiguration.loadBalancerBackendAddressPools = $null
                $ipConfiguration.loadBalancerInboundNatPools = $null
            }
        }
        log -Message "[RemoveBasicLoadBalancerFromVmss] Updating VMSS $($vmss.Name)"

        try {
            $ErrorActionPreference = 'Stop'

            Update-Vmss -Vmss $vmss
        }
        catch {
            $message = "[RemoveBasicLoadBalancerFromVmss] An error occured while updating VMSS '$($vmss.Name)' in resource group '$($vmss.ResourceGroupName)' to remove it from a backend pool on load balancer '$($BasicLoadBalancer.Name)'. Follow the steps at https://aka.ms/basiclbupgradefailure to retry the migration. `nError message: $_"
            log 'Error' $message -terminateOnError
        }

        # Update the VMSS instances
        UpdateVmssInstances -vmss $vmss
    }

    log -Message "[RemoveBasicLoadBalancer] Removing Basic Loadbalancer $($BasicLoadBalancer.Name) from Resource Group $($BasicLoadBalancer.ResourceGroupName)"

    try {
        Remove-AzLoadBalancer -ResourceGroupName $BasicLoadBalancer.ResourceGroupName -Name $BasicLoadBalancer.Name -Force -ErrorAction Stop > $null
    }
    Catch {
        $message = "[RemoveBasicLoadBalancer] A failure occured when attempting to delete the basic load balancer '$($BasicLoadBalancer.Name)'. The script cannot continue as the front end addresses will not be available to reassign to the new Standard load balancer if the Basic LB has not been removed. To recover address the following error, then follow the steps at https://aka.ms/basiclbupgradefailure to retry the migration. `nError message: $_"
        log 'Error' $message -terminateOnError
    }
    log -Message "[RemoveBasicLoadBalancer] Removal of Basic Loadbalancer $($BasicLoadBalancer.Name) Completed"
}

Export-ModuleMember -Function RemoveBasicLoadBalancer