Hyper-V¶

# Read Hyper-V host configuration
Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization"

# Check VMMS service status and configuration
Get-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Services\vmms" |
    Select-Object DisplayName, ImagePath, Start, Type, ObjectName

# Check if Hyper-V role is installed
$hvFeature = Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization" `
    -ErrorAction SilentlyContinue

if ($hvFeature) {
    Write-Output "Hyper-V is installed"
    Write-Output "Data root: $($hvFeature.DefaultExternalDataRoot)"
} else {
    Write-Output "Hyper-V is NOT installed"
}

# Change default VM and VHD paths via Hyper-V Manager cmdlet (recommended)
Set-VMHost -VirtualMachinePath "D:\Hyper-V\VMs" -VirtualHardDiskPath "E:\Hyper-V\VHDs"

# Verify the change in the registry
Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization" |
    Select-Object DefaultExternalDataRoot, DefaultVirtualHardDiskPath

# Direct registry modification (use only if VMMS is not running)
$hvPath = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization"
Set-ItemProperty -Path $hvPath -Name "DefaultExternalDataRoot" -Value "D:\Hyper-V\VMs" -Type String
Set-ItemProperty -Path $hvPath -Name "DefaultVirtualHardDiskPath" -Value "E:\Hyper-V\VHDs" -Type String

# Check Hyper-V memory reservation settings
$hvPath = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization"
Get-ItemProperty $hvPath -Name "MemoryReserve" -ErrorAction SilentlyContinue

# View current MAC address range
$hvPath = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization"
$props = Get-ItemProperty $hvPath
Write-Output "MAC range: $($props.MinimumMacAddress) - $($props.MaximumMacAddress)"

# Change MAC address range (useful to avoid collisions in a cluster)
Set-ItemProperty -Path $hvPath -Name "MinimumMacAddress" -Value "00155D100000" -Type String
Set-ItemProperty -Path $hvPath -Name "MaximumMacAddress" -Value "00155D10FFFF" -Type String

# List Hyper-V virtual switch related services
Get-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Services\VMSMP" -ErrorAction SilentlyContinue |
    Select-Object DisplayName, ImagePath, Start

# Check virtual switch extension protocol parameters
$vmspPath = "HKLM:\SYSTEM\CurrentControlSet\Services\VMSMP\Parameters"
Get-ItemProperty $vmspPath -ErrorAction SilentlyContinue

# List virtual switches via Hyper-V cmdlet
Get-VMSwitch | Select-Object Name, SwitchType, NetAdapterInterfaceDescription | Format-Table -AutoSize

# Find Hyper-V virtual network adapters in the network class registry
$classPath = "HKLM:\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}"

Get-ChildItem $classPath -ErrorAction SilentlyContinue |
    Where-Object {
        $props = Get-ItemProperty $_.PSPath -ErrorAction SilentlyContinue
        $props.DriverDesc -like "*Hyper-V*"
    } |
    ForEach-Object {
        $props = Get-ItemProperty $_.PSPath
        [PSCustomObject]@{
            Key        = $_.PSChildName
            DriverDesc = $props.DriverDesc
            NetCfgInstanceId = $props.NetCfgInstanceId
        }
    } | Format-Table -AutoSize

# Check VMQ (Virtual Machine Queue) settings on the physical adapter
$nicPath = "HKLM:\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}"

Get-ChildItem $nicPath -ErrorAction SilentlyContinue |
    ForEach-Object {
        $props = Get-ItemProperty $_.PSPath -ErrorAction SilentlyContinue
        if ($props.'*VMQEnable' -ne $null -or $props.VMQEnable -ne $null) {
            [PSCustomObject]@{
                Adapter = $props.DriverDesc
                VMQ     = if ($props.'*VMQEnable') { $props.'*VMQEnable' } else { $props.VMQEnable }
                RSS     = $props.'*RSS'
            }
        }
    } | Format-Table -AutoSize

# Check integration services version on the host
Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization\GuestInstaller\Version" `
    -ErrorAction SilentlyContinue

# Check integration services status inside a VM
$services = @("vmicheartbeat", "vmictimesync", "vmickvpexchange", "vmicshutdown", "vmicvss", "vmicguestinterface")

foreach ($svc in $services) {
    $props = Get-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Services\$svc" -ErrorAction SilentlyContinue
    if ($props) {
        [PSCustomObject]@{
            Service     = $svc
            DisplayName = $props.DisplayName
            Start       = $props.Start
            Status      = switch ($props.Start) { 2 { "Auto" } 3 { "Manual" } 4 { "Disabled" } default { $props.Start } }
        }
    }
} | Format-Table -AutoSize

# Read KVP data pushed from the host
Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Virtual Machine\External" -ErrorAction SilentlyContinue

# From the host: push a KVP pair to a VM
$vm = Get-VM "VM-PROD-01"
$kvpComponent = $vm | Get-VMIntegrationService -Name "Key-Value Pair Exchange"

# Create the KVP data item
$kvpData = [System.Management.ManagementObject]::new("root\virtualization\v2:Msvm_KvpExchangeDataItem")
$kvpData.Name = "DeploymentTag"
$kvpData.Data = "Production"
$kvpData.Source = 0

# Add via WMI
$vmMgmt = Get-WmiObject -Namespace "root\virtualization\v2" -Class "Msvm_VirtualSystemManagementService"
$vmObj = Get-WmiObject -Namespace "root\virtualization\v2" -Class "Msvm_ComputerSystem" |
    Where-Object { $_.ElementName -eq "VM-PROD-01" }
$vmMgmt.AddKvpItems($vmObj, @($kvpData.GetText(1)))

# Check Live Migration configuration
Get-VMHost | Select-Object VirtualMachineMigrationEnabled,
    VirtualMachineMigrationAuthenticationType,
    VirtualMachineMigrationPerformanceOption,
    MaximumVirtualMachineMigrations,
    MaximumStorageMigrations |
    Format-List

# Switch to Kerberos authentication for Live Migration
Set-VMHost -VirtualMachineMigrationAuthenticationType Kerberos

# Set Live Migration to use SMB (best performance with RDMA)
Set-VMHost -VirtualMachineMigrationPerformanceOption SMB

# Check which networks are allowed for Live Migration
(Get-VMHost).VirtualMachineMigrationEnabled
Get-VMMigrationNetwork | Format-Table Subnet, Priority -AutoSize

# Add a dedicated migration network
Add-VMMigrationNetwork -Subnet "10.0.100.0/24" -Priority 1

# Increase simultaneous live migrations (default is 2)
Set-VMHost -MaximumVirtualMachineMigrations 4
Set-VMHost -MaximumStorageMigrations 4

# Enable nested virtualization on a VM (VM must be stopped)
$vmName = "VM-DEVTEST-01"
Stop-VM $vmName -Force
Set-VMProcessor -VMName $vmName -ExposeVirtualizationExtensions $true
Start-VM $vmName

# Verify nested virtualization is enabled
Get-VMProcessor -VMName "VM-DEVTEST-01" |
    Select-Object VMName, ExposeVirtualizationExtensions

# Disable dynamic memory and enable MAC spoofing (required for nested VMs)
$vmName = "VM-DEVTEST-01"
Stop-VM $vmName -Force
Set-VMMemory -VMName $vmName -DynamicMemoryEnabled $false
Get-VMNetworkAdapter -VMName $vmName | Set-VMNetworkAdapter -MacAddressSpoofing On
Start-VM $vmName

# Inside the nested VM: check if virtualization extensions are available
$hvCheck = Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization" `
    -ErrorAction SilentlyContinue

if ($hvCheck) {
    Write-Output "Hyper-V components detected in the nested VM"
} else {
    # Check via systeminfo
    systeminfo | Select-String "Hyper-V Requirements"
}

# Check virtual switch status
Get-VMSwitch | Select-Object Name, SwitchType, NetAdapterInterfaceDescription, Id | Format-Table -AutoSize

# Check if the physical adapter is properly bound to the virtual switch
Get-NetAdapter | Where-Object { $_.InterfaceDescription -like "*Hyper-V*" -or $_.InterfaceDescription -like "*I350*" } |
    Select-Object Name, InterfaceDescription, Status, LinkSpeed | Format-Table -AutoSize

# Check VM network adapter status
Get-VM | Get-VMNetworkAdapter |
    Select-Object VMName, SwitchName, Status, IPAddresses | Format-Table -AutoSize

# Check network binding order and Hyper-V switch extension driver
$classPath = "HKLM:\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}"

Get-ChildItem $classPath -ErrorAction SilentlyContinue |
    ForEach-Object {
        $props = Get-ItemProperty $_.PSPath -ErrorAction SilentlyContinue
        if ($props.DriverDesc -like "*Hyper-V*" -or $props.DriverDesc -like "*I350*") {
            [PSCustomObject]@{
                Key          = $_.PSChildName
                DriverDesc   = $props.DriverDesc
                DriverVersion = $props.DriverVersion
                ComponentId  = $props.ComponentId
            }
        }
    } | Format-Table -AutoSize

# Check the Virtual Machine Switch Protocol driver
Get-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Services\VMSMP" -ErrorAction SilentlyContinue |
    Select-Object DisplayName, ImagePath, Start, ErrorControl

# Check the virtual switch parameters
$vmspParams = "HKLM:\SYSTEM\CurrentControlSet\Services\VMSMP\Parameters"
Get-ItemProperty $vmspParams -ErrorAction SilentlyContinue

# Save current switch configuration before reset
$switchName = "vSwitch-Prod"
$switch = Get-VMSwitch $switchName
$adapterName = (Get-NetAdapter |
    Where-Object { $_.InterfaceDescription -eq $switch.NetAdapterInterfaceDescription }).Name

# Save VM-to-switch mapping
$vmNics = Get-VM | Get-VMNetworkAdapter | Where-Object { $_.SwitchName -eq $switchName }
$vmNics | Select-Object VMName, SwitchName, MacAddress |
    Export-Csv "C:\Admin\vm-nic-backup.csv" -NoTypeInformation

Write-Output "Backup saved. Adapter: $adapterName, VMs connected: $($vmNics.Count)"

# Remove the broken virtual switch
Remove-VMSwitch "vSwitch-Prod" -Force

# Clean orphaned registry entries from the switch protocol driver
$vmspParams = "HKLM:\SYSTEM\CurrentControlSet\Services\VMSMP\Parameters"
$switchList = (Get-ItemProperty $vmspParams -Name "SwitchList" -ErrorAction SilentlyContinue).SwitchList

if ($switchList) {
    Write-Output "Orphaned switch entries found: $($switchList.Count)"
    # The Remove-VMSwitch should have cleaned these, but verify
    Get-ItemProperty $vmspParams
}

# Recreate the virtual switch
New-VMSwitch -Name "vSwitch-Prod" -NetAdapterName "Ethernet 2" -AllowManagementOS $true

# Reconnect all VMs to the new switch
$vmNics = Import-Csv "C:\Admin\vm-nic-backup.csv"

foreach ($nic in $vmNics) {
    Get-VM $nic.VMName | Get-VMNetworkAdapter | Connect-VMNetworkAdapter -SwitchName "vSwitch-Prod"
    Write-Output "$($nic.VMName) : Reconnected to vSwitch-Prod"
}

# Verify network connectivity for all VMs
Get-VM | Where-Object { $_.State -eq "Running" } | Get-VMNetworkAdapter |
    Select-Object VMName, SwitchName, Status, IPAddresses | Format-Table -AutoSize