Script that will set all esxi hosts into maintenace mode if no VMs are left running

Set_Evacuated_Esxi_Hosts_Into_Maintenace_Mode.ps1

## This script will put the evacuated esxi hosts into maintenance mode if no VMs are running, checked every X seconds for Y duration ##
## $Script_Runtime_in_Minutes : Duration (in minutes) the script will be running
## $Wait_Time_in_Second_for_Next_Check : Duration (in seconds) to wait for the next check of vmhosts 
## $VMhost_Name_Criteria : This filters the VMhost to be included according the given regular expression eg: ^192.168.0 to include all the esxi hosts starting with 192.168.0  or leave it blank ("") if you want to include all esxi hosts
## Author : Phyoe Wai Paing
## Date : 15.July.2021
## Version : 1.0 : Initial Release

$Script_Runtime_in_Minutes = 30;	## Y duration described in above comment section
$Wait_Time_in_Second_for_Next_Check = 15;	## X duration described in above comment section
$VMhost_Name_Criteria = ""			## Leave it blank or define it in regular expression to include specific exsi hosts (described in above comment section)


$NumberOfLoops = $Script_Runtime_in_Minutes * 60 / $Wait_Time_in_Second_for_Next_Check
for ($i=0;$i -lt $NumberOfLoops; $i++)  
	{ 	
	write-host "`nTime: $((get-date).ToString('hh:mm:ss'))`n-------------------------------------------------";
	Get-vmhost | ?{ $_.name -match $VMhost_Name_Criteria } | % {  
	$NumRunVMs = ($_ | get-vm | ? {$_.Powerstate -eq "PoweredOn"}).Count; 
	If ($NumRunVMs) 
		{  write-host "Host: $($_.Name)  Running VMs: $NumRunVMs" } 
	else 
		{ 
			$HostConnectionState = (Get-VMhost -Name $($_.Name)).ConnectionState 
			If ($HostConnectionState -eq "Maintenance" )
				{
				write-host -fore Cyan "Host is already in maintenance mode: $($_.Name)"
				}
			elseif ($HostConnectionState -eq "Connected")
				{
				write-host -fore green "Host will enter maintenance mode now: $($_.Name)"
				Set-vmhost -VMhost $($_.Name) -State Maintenance | out-null;
				}
			else {
				write-host -fore red "Host is in unknown state: $($_.Name)" 
				}
		} 
		};
		start-sleep -Second $Wait_Time_in_Second_for_Next_Check;  
	}