Test-Connection powershell

Question

I'm a beginner to PS but i am trying to make my life easier creating a button to reboot a computer and then tell me when its online. I've been trying the -Wait parameter but throws off errors. if anyone can point me in the right direction that would be great.

Restart_Computer_Click ={
$again = 1

While($again -ne 'N'){
  $ComputerName = Read-Host "ComputerName"
  #output online
  if (Test-connection $ComputerName -quiet -count 2){
    write-host -foregroundcolor green "$ComputerName is online"
    Restart-computer -computername $ComputerName -Force -Confirm
  }
  else{
   #output -offline
   write-host -foregroundcolor red "$ComputerName is offline"
  }
  $again = read-host "Reboot Again? y/n"
  $again.toUpper() | out-null
}

}

Answer 1

What luck - I've actually spent a great deal of time on this problem as I have to reboot hundreds of servers each month to apply updates. I understand what you're hoping the -wait command will do, and I'm afraid I know why its not working. The restart-computer command just sends a reboot signal to the computer. There's no logic built into powershell to say "reboot the computer and wait for it to come back online", so waiting for the command won't help.

Instead, what your script needs is a couple of extra steps:

• Check the last reboot time of the computer (this will tell you if it has rebooted yet)
• Check if the system has completely booted back up
• If reboot not complete, pause for a bit and try again

See the modified code below. I've tried to add extensive comments so that you can see my logic in adding steps. I've had to adapt my script from running against multiple computers to a single computer, but this should do the trick. My one assumption is that you've already figured out the button click part of the script and just need help waiting for the reboots.

Restart_Computer_Click =
{
    $computer = "localhost"
    $again = 1
    While ($again -ne 'N')
    {
        $ComputerName = Read-Host "ComputerName"
        
        #output online
        if (Test-connection $ComputerName -quiet -count 2)
        {
            write-host -foregroundcolor green "$ComputerName is online"
            Restart-computer -computername $ComputerName -Force -Confirm
            $online = $true
        }

        else 
        {
            #output -offline
            write-host -foregroundcolor red "$ComputerName is offline"
            $online = $false
        }

        # There's no point in checking the reboot sequence if the computer is offline, so 
        # let's ignore the process if its offline

        if ($online -eq $true)
        {
            # here's the while loop that will keep checking for the status of the rebooted computer
            while ($reboot_complete -ne $true)
            {
                # First, let's sleep for two minutes to give the system time to reboot
                # My systems generally have to install updates, so I have to grant a
                # generous reboot time
                start-sleep -Seconds 120

                # If the computer is in the middle of restarting, we can't check the boot status, so we
                # need to wait a little longer
                if (Test-Connection $computer -quiet -count 1)
                {
                    $lastboot = Get-WMIObject Win32_OperatingSystem -ComputerName $computer -EA SilentlyContinue
                    $lastbootdate = $lastboot.converttodatetime($lastboot.LastBootUpTime)
                    $time_elapsed = (get-date) - $lastbootdate

                    # This is the main statement that's going to tell us if the system has rebooted
                    # The time elapsed is the time difference between right now and the time the computer 
                    # was last rebooted. The time elapsed is basically the difference in time. If there's
                    # less than 10 minutes of difference, I assume its rebooted from the script. If its 
                    # older than that, I assume it hasn't rebooted yet. For example, you can pull a system's 
                    # time while its applying updates as part of the reboot process.
                
                    if ($time_elapsed.TotalMinutes -lt 10)
                    {
                       $reboot_complete = $true     
                    }
                }
            }
        }





        $again = read-host "Reboot Again? y/n"
        $again.toUpper() | out-null

    }
}