How to confirm system initialization is complete using using PowerShell?

user_925063 0
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I have a working PS script that gets the boot time of remote servers

#$ServerArray is the list of servers

$cso = New-CimSessionOption -Protocol Dcom
$cs = New-CimSession -ComputerName $ServerArray -SessionOption $cso
Get-CimInstance -CimSession $cs -ClassName win32_operatingsystem -OperationTimeoutSec 10 | select csname, Caption, lastbootuptime | sort lastbootuptime | format-table -autosize

Result:

csname         Caption                                   lastbootuptime
------         -------                                   --------------
server1        Microsoft Windows Server 2012 R2 Standard 10/30/2021 3:07:23 AM
server2        Microsoft Windows Server 2012 R2 Standard 10/30/2021 3:12:35 AM
server3        Microsoft Windows Server 2012 R2 Standard 10/30/2021 3:13:34 AM

Are there any other details that can be extracted using PowerShell or another API to show that the server has properly booted?

powershell-5.1 powershell windows
1 Answers

Note: This may be difficult to use PowerShell for depending on the mechanism of execution; PowerShell Remoting is not available during early stages of boot, nor is an interactive CLI. However, some agents or services (like VMware Tools as an example) can facilitate remote execution at times like these. Scheduled Tasks can also be leveraged to run code locally during some earlier boot phases. Though this answer centers around PowerShell, the general information can be used with other programming languages as well.

There are boot states of Windows you can attempt to look for ways to check these but the most reliable way I've found to know if the computer is in a state for a user to log on is to wait for Get-Process winlogon to return a process back. Once winlogon is running, the computer is near or able to facilitate logon sessions, pending completion of GPO application.

This SuperUser answer explains how to use the Windows Performance Toolkit (part of the Windows SDK) to initiate a boot trace and disseminate its report, but that isn't the focus of this question or answer. I'm including it here to show that waiting for winlogon is the right way to identify when the system is ready for interaction; execution of winlogon is actually the final Windows boot phase and that answer exemplifies this.

Note: Technically, logging in and waiting for scheduled tasks to complete on login is the final step but that portion comes after after kernel boot has completed, and can be repeated for multiple logon sessions. I don't consider this part of the "boot sequence" or system initialization.

As for the boot phases of Windows I've only been able to generate a report of a boot trace using xbootmgr. I'm not sure there is a documented API (win32 or otherwise) exposed to the userspace to check for the current boot phase outside of the boot trace. At this time I can only recommend looking at environmental details to know the current boot phase (such as checking for the winlogon process), although I'm not familiar enough with the environments of the other boot phases to make additional recommendations here.

If I learn more information about the other phases I will update this answer.

user_5846760
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