#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : Virtual machines lose network after a host change
    Fix   : Make the switch names match across every host
    Source: https://jbtecwiz.com/support/srv-clu-vm-network

    Run as     : Elevated PowerShell
    Expect     : 40 minutes
    Risk       : medium
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    Machines lose network on one host only.

    HOW TO UNDO IT
    Switch names can be renamed back.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 5"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  Virtual machines lose network after a host change' -ForegroundColor White
Write-Host '  Make the switch names match across every host' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: medium   Reversible   40 minutes'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'Compare the switch names across every host in the cluster.' -Why 'A trailing space or a different capitalisation is enough. The comparison across all hosts in one command is the quickest way to see it, and it is almost always a typo made when a host was added.' -Command {
    Get-ClusterNode | ForEach-Object {
      $n = $_.Name
      Get-VMSwitch -ComputerName $n | Select-Object @{n='Host';e={$n}},Name,SwitchType,NetAdapterInterfaceDescription
    } | Format-Table -AutoSize
}

Invoke-Step -Number 2 -Do 'Rename the switch on the odd host to match the others exactly.' -Command {
    Rename-VMSwitch -Name 'vSwitch-Prod ' -NewName 'vSwitch-Prod' -ComputerName HV03
}

Invoke-Step -Number 3 -Do 'Reconnect any virtual machine whose adapter shows a configuration error.' -Command {
    Get-VM | Get-VMNetworkAdapter | Where-Object Status -ne 'Ok' | Format-Table VMName,Name,SwitchName,Status
    Get-VM VM01 | Get-VMNetworkAdapter | Connect-VMNetworkAdapter -SwitchName 'vSwitch-Prod'
}

Invoke-Step -Number 4 -Do 'Check the VLAN assignment came across with the machine.' -Command {
    Get-VM | Get-VMNetworkAdapterVlan | Format-Table VMName,OperationMode,AccessVlanId
}

Invoke-Step -Number 5 -Do 'Confirm the physical switch port for the new host trunks the same VLANs as the others.' -Manual

Write-Rule "  Confirm it worked"
Show-Prose 'The machine migrates to any host and keeps its network.' 'White'
Write-Host ''
if (-not $DryRun) {
    Get-VM | Get-VMNetworkAdapter | Format-Table VMName,SwitchName,Status,IPAddresses -AutoSize
}

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/srv-clu-vm-network' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: Switch names can be renamed back.' 'DarkGray'
Write-Rule