Script: How to Put ESXi Hosts InTo Maintenance Mode, Reboot ESXi Hosts, Reconnect ESXi and Loop Across All Hosts Cluster Using Powershell or Powercli

Param([Parameter(Mandatory=$true,ValueFromPipeline=$true)][string[]]$Cluster)
$ClusterName = "*$Cluster*"

## Start-Transcript
Start-Transcript -Path C:\Temp\hostreboot-transcript.txt

## Set Connection String
$cred = Get-Credential
$vCenters = "lab-vc01.lab.local", "lab-vc02.lab.local"
Connect-VIServer -Server $vCenters  -Credential $cred

## Set Parameters

## Param([Parameter(Mandatory=$true,ValueFromPipeline=$true)][string[]]$Cluster)

## Param([Parameter(Mandatory=$true)][String]$Cluster)

Get-Cluster $ClusterName
if((Get-Cluster $ClusterName).count -gt 1)
{
Write-Host "Please Specify Less Than 1 Cluster"

## if the cluster name specified matches more than 1 cluster, the operation will be aborted

exit
}
else {
	write host "$ClusterName is not more than 1 Cluster"
}

## Grab host lists and save in txt file - make sure you have enough permission to write into dir

(Get-Cluster $ClusterName |Get-VMHost).Name | Out-File C:\lab\LabHostReboot.txt 

cd c:\lab\

Get-Content .\LabHostReboot.txt  | %{ 
    $Server = $_;
    Write-Host -ForegroundColor Green "$Server"
    Write-Host -ForegroundColor Yellow "`tServer Is Entering Maintenance Mode"
    Set-VMHost $Server -State maintenance -Evacuate | Out-Null
 
    Write-Host -ForegroundColor Yellow -NoNewline "`tServer is Rebooting"
    Restart-VMHost $Server -Confirm:$false  | Out-Null
 
 ## Wait 5 mins from reboot to check connection state of the Host
    do {
        sleep 2
        $ServerState = (Get-VMHost $Server).ConnectionState
        Write-Host -ForegroundColor Yellow -NoNewline "."
    } while ($ServerState -ne "NotResponding")
    Write-Host -ForegroundColor Yellow -NoNewline "(Server is powered down)"
 
 ## Another 5 mins wait post reboot to make sure server is up and in MM 
    do {
        sleep 2
        $ServerState = (Get-VMHost $Server).ConnectionState
        Write-Host -ForegroundColor Yellow -NoNewline "`."
    } while ($ServerState -ne "Maintenance")
    Write-Host -ForegroundColor Yellow "(Server is Powered Up)"
 
 ## Set connection state to connected post reboot

    Write-Host -ForegroundColor Yellow "`tServer Exiting Maintenance Mode"
    Set-VMHost $Server -State Connected  | Out-Null
    Write-Host -ForegroundColor Yellow "`tHost Reboot Cycle Done!"
    Write-Host ""
}

Stop-Transcript