Function to test AD health. It utilizes dcdiag and produces tabular output

Test-ADHealth.ps1

function Test-ADHealth {
    [CmdletBinding()]
    Param(
        [Parameter(ValueFromPipeline = $true, mandatory = $true)]$DomainName,
        [Parameter(ValueFromPipeline = $true, mandatory = $true)][pscredential]$Credential
    )

    $Report = @()
    $dcs = Get-ADDomainController -Filter * -Server $DomainName -Credential $Credential

    $jobs = foreach ($Dcserver in $dcs.HostName) {
        $Job = Start-Job -ScriptBlock {
            param($DC)

            $Result = [pscustomobject] @{
                DCName              = $DC
                Ping                = $null
                Netlogon            = $null
                NTDS                = $null
                DNS                 = $null
                DCDIAG_Netlogons    = $null
                DCDIAG_Services     = $null
                DCDIAG_Replications = $null
                DCDIAG_FSMOCheck    = $null
                DCDIAG_Advertising  = $null
            }

            if (Test-Connection -ComputerName $DC -Count 2 -Quiet) {
                $Result.Ping = "OK"

                $output = Get-Service -Name DNS, NTDS, Netlogon -ComputerName $DC -ErrorAction SilentlyContinue | Select-Object Name, Status

                # Netlogon Service Status
                $netlogonstatus = ($output | Where-Object { $_.Name -eq "Netlogon" } | Select-object Status).Status
                if ($netlogonstatus -eq "Running") {
                    $Result.Netlogon = "OK"
                }
                else {
                    $Result.Netlogon = $netlogonstatus
                }

                # NTDS Service Status
                $NTDSstatus = ($output | Where-Object { $_.Name -eq "NTDS" } | Select-object Status).Status
                if ($NTDSstatus -eq "Running") {
                    $Result.NTDS = "OK"
                }
                else {
                    $Result.NTDS = $NTDSstatus
                }

                # DNS Service Status                
                $DNSstatus = ($output | Where-Object { $_.Name -eq "DNS" } | Select-object Status).Status
                if ($DNSstatus -eq "Running") {
                    $Result.DNS = "OK"
                }
                else {
                    $Result.DNS = $DNSstatus
                }
                
                # Dcdiag netlogons "Checking now"
                $dcdiagnetlogon = dcdiag /test:netlogons /s:$DC
                if ($dcdiagnetlogon -match "passed test NetLogons") {
                    $Result.DCDIAG_Netlogons = "OK"
                }
                else {
                    $Result.DCDIAG_Netlogons = (($dcdiagnetlogon | Select-String "Error", "warning" | ForEach-Object { $_.Line.Trim() }) -join "`n") + "`n`nRun dcdiag /test:netlogons /s:$DC"
                }

                # Dcdiag services check
                $dcdiagservices = dcdiag /test:services /s:$DC
                if ($dcdiagservices -match "passed test services") {
                    $Result.DCDIAG_Services = "OK"
                }
                else {
                    $Result.DCDIAG_Services = (($dcdiagservices | Select-String "Error", "warning" | ForEach-Object { $_.Line.Trim() }) -join "`n") + "`n`nRun dcdiag /test:services /s:$DC"
                }

                # Dcdiag Replication Check
                $dcdiagreplications = dcdiag /test:Replications /s:$DC
                if ($dcdiagreplications -match "passed test Replications") {
                    $Result.DCDIAG_Replications = "OK"
                }
                else {
                    $Result.DCDIAG_Replications = (($dcdiagreplications | Select-String "Error", "warning" | ForEach-Object { $_.Line.Trim() }) -join "`n") + "`n`nRun dcdiag /test:Replications /s:$DC"
                }

                # Dcdiag FSMOCheck Check
                $dcdiagFsmoCheck = dcdiag /test:FSMOCheck /s:$DC
                if ($dcdiagFsmoCheck -match "passed test FsmoCheck") {
                    $Result.DCDIAG_FSMOCheck = "OK"
                }
                else {
                    $Result.DCDIAG_FSMOCheck = (($dcdiagFsmoCheck | Select-String "Error", "warning" | ForEach-Object { $_.Line.Trim() }) -join "`n") + "`n`nRun dcdiag /test:FSMOCheck /s:$DC"
                }

                # Dcdiag Advertising Check
                $dcdiagAdvertising = dcdiag /test:Advertising /s:$DC
                if ($dcdiagAdvertising -match "passed test Advertising") {
                    $Result.DCDIAG_Advertising = "OK"
                }
                else {
                    $Result.DCDIAG_Advertising = (($dcdiagAdvertising | Select-String "Error", "warning" | ForEach-Object { $_.Line.Trim() }) -join "`n") + "`n`nRun dcdiag /test:Advertising /s:$DC"
                }
            }
            else {
                $Result.Ping = "DC is down"
                $Result.Netlogon = "DC is down"
                $Result.NTDS = "DC is down"
                $Result.DNS = "DC is down"
                $Result.DCDIAG_Netlogons = "DC is down"
                $Result.DCDIAG_Services = "DC is down"
                $Result.DCDIAG_Replications = "DC is down"
                $Result.DCDIAG_FSMOCheck = "DC is down"
                $Result.DCDIAG_Advertising = "DC is down"
            }

            $Result | Select-Object DCName, Ping, NTDS, Netlogon, DNS, DCDIAG_Netlogons, DCDIAG_Services, DCDIAG_FSMOCheck, DCDIAG_Replications, DCDIAG_Advertising
        } -ArgumentList $Dcserver

        $Job
    }

    $null = Wait-Job -Job $jobs

    $Report = foreach ($Job in $jobs) {
        Receive-Job -Job $Job
    }

    Remove-Job -Job $jobs    

    $Report = $Report | Select-Object DCName, Ping, NTDS, Netlogon, DNS, DCDIAG_Netlogons, DCDIAG_Services, DCDIAG_FSMOCheck, DCDIAG_Replications, DCDIAG_Advertising
    return $Report
}

Test-ADHealth -DomainName "<XYZ>" -Credential Get-Credential