Export SCCM task sequence variables with PowerShell

Whenever starting with a new technology or project, I try to gather as much information as possible to get an idea of what I'm working with.  I've recently started working with SCCM task sequences, and similar to MDT, there are built-in task sequence steps that cover the basic tasks that most system administrators need to perform.  However, as environments become more complex and we are asked to do more and to do it efficiently, we sometimes need to get deep into the weeds and pull out a hidden gem.

There is a trove of data that is required to perform actions in a task sequence that is hidden from view. SCCM uses this data to determine which servers to talk to, where packages are located, which step is currently running, and much more.  If we want to be able to use it, we need to know what is there. There are blog posts from years ago explaining how to export this information using VBscript, but this is 2017 and we deserve a PowerShell way to do it!  This code will export all task sequence variables, including those defined on collections and devices.



With the line below, we are creating a new PowerShell object based on the SCCM task sequence COM object and storing it in $TSEnv.

$TSEnv = New-Object -ComObject Microsoft.SMS.TSEnvironment

There are a few interesting methods to explore on this object, but for now we will focus on two of them:

1. GetVariables()
2. Value()

The first method allows us to query the currently running task sequence for the names of all available task sequence variables.  The second method returns the value of the variable specified inside the parenthesis.  By using both of them together in a loop, we can return a list of every variable and it's respective value and store it in a variable.  We then use Out-File to write the variables to a text file on the system drive (X: if run in WinPE).

Now we need to add the script to a task sequence and run it.  There are a few of ways to invoke PowerShell code in a task sequence:

1. Run PowerShell Script step and providing a script name that exists within a package
2. Run Command Line step and invoking PowerShell.exe with the -File parameter
3. Run Command Line step and invoking PowerShell.exe with the -Command parameter

There are plenty of guides on how to use items 1 and 2 above, so let's play with the third.  To do this, we need to concatenate all of the commands so that they run in one PowerShell instance.  This can be done by using a semi-colon, which tells PowerShell to expect more code before exiting.  When done, it looks like this:

We can then paste this code into a Run Command Line step in the task sequence and deploy it to an SCCM client.  

After the task sequence completes, you will find a file in $ENV:SystemDrive\Windows\Temp named TSVariables.txt that contains a key=value listing of the variables.  One word of caution is that this exports ALL task sequence variables, including sensitive and masked variables such as the SCCM client push credentials (noted by a variable name starting with "_SMSTSReserved").  If you want to avoid exporting these, you can update the GetVariables code to match the code below.

$Vars = $TSEnv.GetVariables() | Where-Object {$_ -notmatch 'Password' -OR $_ -notmatch 'Reserved'}

You can add as many -OR statements to the code to filter sensitive information.  In a later post we'll go through some of the interesting variables and what they can be used for.

Quick Hits: Set-CMSite and Set-AdaptivaServer

It's eclipse star-gazing time, so the blog post this weekend comes to you from the road and features two functions that I have used extensively when working in my lab environment for SCCM and Adaptiva.

Set-CMSite

This function requires local administrator rights on the device and switches the site that your SCCM agent is connected to.  After execution, you can use my Get-CMLog function to follow along with the logs while your machine connects to the new infrastructure and starts performing registration activities.

Set-CMSite on Github



Set-AdaptivaServer

If you have any low-bandwidth locations being served by your SCCM infrastructure, you may have looked into ways to easily provide content to those locations.  One option is to use an Alternate Content Provider that can cache the content locally and uses P2P storage.  One that I have been testing is Adaptiva OneSite.  With multiple environments, having an easy way to switch a client from one infrastructure to another similar to how we do with Set-CMSite above, is crucial.

Set-AdaptivaServer on Github

Note: To maintain cached content at the branch site, you must use the built-in SCCM migration tool to mirror content to the new SCCM infrastructure and also publish the content to the new Adaptiva server.  Otherwise, the content will fail a hash check and will need to be downloaded across the WAN again.

SCCM Log Parser

Anyone who has ever worked with SCCM loves and adores CMTrace.exe for it's ability to parse the System Center logs. Countless headaches have been adverted in it's name.  Still, it leaves quite a bit to be desired.  To address some of the short-comings, Microsoft has released CMLogViewer.exe.  This new tool supports quick filters, merging log files, and advanced filters.  Even with the added features, it still lacks the flexibility that PowerShell can offer.

I started my adventure to do more by searching online for anything that met my needs:

• Read logs in the SCCM format
• Parse a single log or multiple logs (must provide filename as a property)
• Provide either local or UTC timestamps for global troubleshooting
• Accepts logs directly or via pipeline

After not finding anything suitable, I set about writing my own.  Thankfully the fields in the log file are self-explanatory as key=value pairs and we can use basic regex to capture them.

• Message
• Time
• Date
• Component
• Context
• Type
• Thread
• File

To satisfy the local and UTC timestamps requirement, I had to add some additional regex capture groups that were then passed to the [DateTime]::ParseExact .Net method.  I then added the fields into a [PSCustomObject].  The regex and object were then wrapped in a foreach loop that processes log lines read in via Get-Content.  Since I also had a requirement of passing in multiple files and showing which line came from which log, I captured the current file name via Split-Path and also added that as a property to the object.  And to support the ability to specify logs through the pipeline, a Process block was added and then a loop to read in each file.

Meeting these requirements allow us to do fun stuff like the following:

Show me the log entries in SMSTS.log
   Get-CMLog smsts.log

Show me all log entries for CM logs and sort them by date

   Get-ChildItem -Path C:\Windows\CCM\Logs | Get-CMLog | Sort-Object UTCTime

Show me any log entry with "Error" in the message text

   Get-CMLog -Path .\SMSTS.log | ?{$_.Message -match 'Error'}

Show me all log entries for logs that contain an error

   Get-ChildItem -Path C:\Windows\CCM\Logs | Select-String -Pattern 'error' | Select -Unique Path | Get-CMLog

The full code is available below and on Github.