Add multiple powershell versions to Vscode

Here is the quick and dirty way to add multiple PowerShell versions to VSCode, and switch between them quickly.

It’s often times advantageous to quickly switch between multiple versions of a programming language when coding to ensure that your code works on multiple platforms.  For me, that is switching between Windows PowerShell and multiple versions of Microsoft PowerShell (PowerShell Core).  He’s how to easily do it in VSCode.

First, I am going to assume you have the PowerShell extension already installed in VSCode.  If not, hit F1 (Ctrl-Shift-P) to open the command palette, and type this


ext install powershell

Now, let’s get some different PowerShell versions.  This is the link to PowerShell 7 preview 5.  Down that and extract it to any directory you want.  In this example I will also be using the latest stable version – 6.2.3.  In this example I have downloaded them both to the c:\pwsh directory.

Open VSCode, and create a new file.  Save the file with a .ps1 extension.  Notice how the terminal automatically starts PowerShell, and that the little green number in the lower right says 5.1?  That’s because VSCode is smart enough to look in common locations for PowerShell versions, and will add those automatically to your session options.  Since we are putting the version in a non-typical location, we have to edit our settings.json.  The easiest way to do it is this is to hit F1 (Ctrl-Shift-P), and type ‘language’.  Select “Configure Language Specific Settings”


You will open the settings.json for your user and language.  If you haven’t done much with VSCode, it probably looks something like this:


    "workbench.iconTheme": "vscode-icons",
    "team.showWelcomeMessage": false,
    "markdown.extension.toc.githubCompatibility": true,
    "git.enableSmartCommit": true,
    "git.autofetch": true,
    "[powershell]": {}

To add our new versions, we need to add just a bit to this file.  We are going to add powershell.powerShellAdditionalExePaths settings – in our case 2 of them.  The important parts are to make sure you are escaping the “\” slashes with another slash, and just follow normal JSON formatting requirements.  Continuing with my example, my settings.json looks like this:

    "workbench.iconTheme": "vscode-icons",
    "team.showWelcomeMessage": false,
    "markdown.extension.toc.githubCompatibility": true,
    "git.enableSmartCommit": true,
    "git.autofetch": true,
    "[powershell]": {},
    "powershell.powerShellAdditionalExePaths": [
            "exePath": "C:\\pwsh\\7.p5\\pwsh.exe",
            "versionName": "PowerShell Core 7p5"
            "exePath": "C:\\pwsh\\6.2.3\\pwsh.exe",
            "versionName": "PowerShell Core 6.2.3"
    "powershell.powerShellDefaultVersion": "PowerShell Core 7p5",
    "powershell.powerShellExePath": "C:\\pwsh\\7.p5\\pwsh.exe"

Save the settings file, and if you have an open terminal, either exit it, or crash/reload.  This will force VSCode to reload the settings file.  If you have done it correctly, if you click on the little green version number in the lower right, you should see something like this:

Switch between them, and verify you see the various version with $PSVersionTable

SCOM Incremental discovery

Limitless possibilities – very little code

One of the biggest pet peeves that I’ve had with SCOM discovery is that it was always very agent biased.  If you wanted to discover IIS, for example, the agent would look for the bits and pieces of IIS installed on a server.  While that works fine for most classes and objects, it does pose some limitations.  What if I wanted to add additional properties to an existing object, or mark a server with a custom attribute?  A common work around was to ‘tattoo’ a system with a reg key or perhaps a file, and then discover that via the normal mechanism.  That seems like extra steps for something that should be relatively easy.  I want to run discovery on something other than the agent, and have that discovery data roll up to the agent.

Why would someone want to perform discovery ‘remotely’?  Well, maybe you have a CMDB or an application to server relationship database.  Would you rather put a regkey on every server with the application information, or just query the database?  Imagine being able to have application owner properties (email, phone, manager, etc…) in SCOM as a property for every server, but without having to touch the server at all – no more regkeys or property files.


This class – IncrementalDiscoveryData – is an amazingly powerful tool.  The idea is that you can submit additional discovery data for an existing object, or even create brand new objects like normal.  The best way to imagine this is to look at the code itself:

$data = (invoke-sql @DBParams -method query -statement "select * from SomeDataTable").tables.rows 
New-SCOMManagementGroupConnection -ComputerName “localhost”
$mg = Get-SCOMManagementGroup

foreach ($row in $data){
    $class = get-scomclass -displayname $row.ClassName
    $ClassObject=New-Object Microsoft.EnterpriseManagement.Common.CreatableEnterpriseManagementObject($mg,$class)
    $servername = $row.servername
    $ClassObject[$Class.FindHostClass(),“PrincipalName”].Value = "$servername"
    $ClassObject[$Class,“AppID”].Value = $row.AppID
    $ClassObject[$Class,“MonitorCI”].Value = $row.MonitorCI
    $discovery=New-Object Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData

The first 3 lines are pretty straight forward.  A simple function that querys a database (invoke-sql), creating a connection the the local management server, and getting the management group.

Then we go row by row with what’s in the table.  In this case the table looks something like this:

ClassName ServerName AppID MonitorCI
Microsoft.Windows.Computer server01 COTS1 AssignmentGroup1
Microsoft.Windows.Computer server02 Custom2 AssignmentGroup2

The code is going to get the class (in this case $row.classname, which is Microsoft.Windows.Computer), then create a new instance of that class (even if the object exists – we won’t overwrite anything not in the discovery data).  We find the host using the servername , add a couple of our new attributes – AppID and MonitorCI – and then create our discovery object.  That is where the magic happens – 

$discovery=New-Object Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData

This is the bit that creates the actual discovery object.  Since it’s incremental, we aren’t going to mess with anything already in that object, just update the bits that we add to the discovery object.  In this case, we are adding the $ClassObject that we populated with our additional bits of data – AppID and MonitorCI.    Two more lines, and we have our remotely discovered data as properties in our server object.


With just that little bit of code we are able to store attributes, properties, configurations, or anything else in a central database and have a simple PowerShell script that updates the objects in SCOM with that discovery data!  Not only that, those items are not rolled up to some random object, we can roll them up to the exact object we want.  No more regkey tattoos, or configuration files that you have to keep update to date on servers.  

Powershell and Parsing html code in Core

When working on a PowerShell webservice, I came across an interesting problem that I think is only going to crop up more and more.  This webservice takes a json payload, performs some simple manipulation on the data, kicks off some automation, and logs some events.  Part of the payload is html code, however.  Of course the json payload doesn’t care, but when it was coming into PowerShell it was being interpreted as a string.  That meant that when you looked at the string, you literally saw html code:

<BODY><H3>OPEN Problem 256 in environment <I>EPG</I></H3>
                               <B>1 impacted infrastructure component</B>
                               <DIV><SPAN>Process</SPAN><BR><B><SPAN style="FONT-SIZE: 120%; COLOR: #dc172a">bosh-dns-health</SPAN></B><BR>
                               <P style="MARGIN-LEFT: 1em"><B><SPAN style="FONT-SIZE: 110%">Network problem</SPAN></B><BR>Packet retransmission rate for process bosh-dns-health on host 
                               cloud_controller/<GUID> has increased to 18 %</P></DIV>
                               Root cause
                               <DIV><SPAN>Process</SPAN><BR><B><SPAN style="FONT-SIZE: 120%; COLOR: #dc172a">bosh-dns-health</SPAN></B><BR>
                               <P style="MARGIN-LEFT: 1em"><B><SPAN style="FONT-SIZE: 110%">Network problem</SPAN></B><BR>Packet retransmission rate for process bosh-dns-health on host 
                               cloud_controller/<GUID> has increased to 18 %</P></DIV>
                               <P><A href="<GUID>/#problems/problemdetails;pid=-<GUID>">Open in Browser</A></P></BODY> 

I wanted to put this data in the events I was logging, but I obviously didn’t want it to look like this.  There isn’t a PowerShell cmdlet for ‘ConvertFrom-HTML’, although that would be great.  I could have tried to parse the text and remove the formatting, but that would be a pain trying to escape the right characters and account for all of the html tags.  I found several ways online to handle this – namely creating a ‘HTMLFile’ object, writing the html code into it, and then extracting out the innertext property of the object.  This works fine in some environments, but throws a weird error if you don’t have Office installed.  Here is the code:

$HTML = New-Object -Com "HTMLFile"

And the error it throws when Office isn’t installed:

Method invocation failed because [System.__ComObject] does not contain a method named 'IHTMLDocument2_write'.

There is also a catch here – that error will also be thrown if you are trying this in PowerShell Core/Microsoft PowerShell (not Windows PowerShell – i.e. anything under 5.x)!  Fortunately, there is a quick fix:

$HTML = New-Object -Com "HTMLFile"
try {
catch {
    $encoded = [System.Text.Encoding]::Unicode.GetBytes($htmlcode)
$text = ($html.all | Where-Object { $_.tagname -eq 'body' } | Select-Object -Property innerText).innertext

A simple try/catch, and it works great.  I am going to create a new repo in GitHub and make this a new function.  Hopefully you haven’t wasted too much time trying to track this down – it took me a while, and it wasn’t until I stumbled upon a similar solution on StackOverflow ( that I was able to wrap it up.  Expect the cmdlet/function soon!

Azure ARM Fragments

SCOM Trick adopted for Azure ARM

I am working on a project for a very popular conference – working on backend automation that controls everything from speaker coordination to session scheduling.  The current task at hand involves deploying the entire suite of Logic Apps, Azure Automation accounts, Azure Functions, etc…  These would all be deployed to a new Resource Group.  When deploying these resources for a new conference a few things change – changing the conference name from ‘Jazz’ to ‘Midway’ for example, or changing the backend data sources.  

Normally you would use Azure ARM Template Parameters to pass these values when you deploy the resources, and you would be absolutely right!  They are powerful assets to have in your pocket.  It does get a bit dodgy, however, when you start to deploy Logic Apps in the ARM template and those Logic Apps have parameters of their own.  

Logic Apps have parameters and variables all their own, and they are defined just like parameters and variables in ARM templates.  When you want to deploy a Logic App that has parameters you can put them in the ARM Template and reference them in the Logic App, or you can use an ARM template expression in the Logic App.  The latter is not a popular idea, and the former doesn’t evaluate the parameters until the execution of the Logic App.  That obviously makes it difficult to work on the Logic App after it’s deployed.

That’s when I got the idea of using a popular SCOM tool – SCOM Fragments by Kevin Holman – in order to get the best of both worlds.  I wanted a quick way to deploy, and a quick way to edit after deployment.  Cake and all that….

The idea is simplistic – Find/Replace what you want to change before you deploy.  Sounds simple, and it is!  That is essentially how the SCOM Fragments work, and the same idea can be utilized here.  Say, for example, you have a simple Conference Name parameter you want to change.  The first thing you would do is build your Logic App like normal, keeping in place a static conference name.  Export that template.  Now, at the top of the template, add a new parameter to the parameters section in the template, like this:

    "$schema": "",
    "contentVersion": "",
    "parameters": {
        "Conference_Name": {
            "metadata": {
                "defaultValue": "###Awesome_Conference_Name###",
                "description": "Name of the conference - i.e. Management Conference 2019"

Now, find your static conference name down in the code for the Logic App itself, and replace the name with ###Awesome_Conference_Name###.   That’s it!  That is all that is needed to prepare your template for a rapid deployment.  When you need to deploy this template, simply Find/Replace ###Awesome_Conference_Name### with whatever text you want – i.e. “My Super Conference 2019”.  It will update it both in the parameters section, and in the code itself.  Do we really need the Parameter at the top of ARM template, especially if we are just going to replace the text ourselves before we deploy?  That answer is no, but it does help immensely when keeping track when you have a ton of parameters:

    "$schema": "",
    "contentVersion": "",
    "parameters": {
        "Conference_Name": {
            "metadata": {
                "defaultValue": "###Awesome_Conference_Name###",
                "description": "Name of the conference - i.e. Management Conference 2019"
        "Sharepoint_Base_URL": {
            "defaultValue": ""
        "Sharepoint_Speaker_ListName": {"defaultValue": "###Sharepoint_Speaker_ListName###"},
        "Sharepoint_Session_ListName": {"defaultValue": "###Sharepoint_Session_ListName###"},
        "Sharepoint_Session_Selection_Team_ListName": {"defaultValue": "###Sharepoint_Session_Selection_Team_ListName###"},
        "Sharepoint_Approved_Sessions_ListName": {"defaultValue": "###Sharepoint_Approved_Sessions_ListName###"},
        "Speaker_Agreement_URL": {"defaultValue": "###Speaker_Agreement_URL###"},
        "Session_Submission_FormName": {"defaultValue": "###Session_Submission_FormName###"},
        "Sched_Speakers_API": {"defaultValue": "###Sched_Speakers_API###"},
        "Sched_Sessions_API": {"defaultValue": "###Sched_Sessions_API###"},
        "Sched_Base_URL": {"defaultValue": "###Sched_Base_URL###"},
        "Sched_API_Key": {"defaultValue": "###Sched_API_Key###"},
        "MediaPack_URL": {"defaultValue": "###MediaPack_URL###"},

By putting the parameters in your code, even though you aren’t going to use them in the way they are intended, you can easily see which ones you need to replace in one place.  

Powershell – what modules are in use?

There comes a time when you are neck deep in code, and come to the realization that one of your modules could really use a tweak.  There is just one problem – what other scripts are using this module?  What if you wanted to inventory your scripts and the modules that each script is using?  This was the main use-case for this post.  I have a scripts directory, and want to get a quick inventory of what modules each one is using.  

First, the function:

#requires -version 3.0
Function Test-ScriptFile {
    Test a PowerShell script for cmdlets
    This command will analyze a PowerShell script file and display a list of detected commands such as PowerShell cmdlets and functions. Commands will be compared to what is installed locally. It is recommended you run this on a Windows 8.1 client with the latest version of RSAT installed. Unknown commands could also be internally defined functions. If in doubt view the contents of the script file in the PowerShell ISE or a script editor.
    You can test any .ps1, .psm1 or .txt file.
    .Parameter Path
    The path to the PowerShell script file. You can test any .ps1, .psm1 or .txt file.
    PS C:\> test-scriptfile C:\scripts\Remove-MyVM2.ps1
    CommandType Name                                   ModuleName
    ----------- ----                                   ----------
        Cmdlet Disable-VMEventing                      Hyper-V
        Cmdlet ForEach-Object                          Microsoft.PowerShell.Core
        Cmdlet Get-VHD                                 Hyper-V
        Cmdlet Get-VMSnapshot                          Hyper-V
        Cmdlet Invoke-Command                          Microsoft.PowerShell.Core
        Cmdlet New-PSSession                           Microsoft.PowerShell.Core
        Cmdlet Out-Null                                Microsoft.PowerShell.Core
        Cmdlet Out-String                              Microsoft.PowerShell.Utility
        Cmdlet Remove-Item                             Microsoft.PowerShell.Management
        Cmdlet Remove-PSSession                        Microsoft.PowerShell.Core
        Cmdlet Remove-VM                               Hyper-V
        Cmdlet Remove-VMSnapshot                       Hyper-V
        Cmdlet Write-Debug                             Microsoft.PowerShell.Utility
        Cmdlet Write-Verbose                           Microsoft.PowerShell.Utility
        Cmdlet Write-Warning                           Microsoft.PowerShell.Utility

    Original script provided by Jeff Hicks at (

        [Parameter(Position = 0, Mandatory = $True, HelpMessage = "Enter the path to a PowerShell script file,",
            ValueFromPipeline = $True, ValueFromPipelineByPropertyName = $True)]
        [ValidatePattern( "\.(ps1|psm1|txt)$")]
        [ValidateScript( { Test-Path $_ })]
    Begin {
        Write-Verbose "Starting $($MyInvocation.Mycommand)"  
        Write-Verbose "Defining AST variables"
        New-Variable astTokens -force
        New-Variable astErr -force
    Process {
        Write-Verbose "Parsing $path"
        $AST = [System.Management.Automation.Language.Parser]::ParseFile($Path, [ref]$astTokens, [ref]$astErr)

        #group tokens and turn into a hashtable
        $h = $astTokens | Group-Object tokenflags -AsHashTable -AsString
        $commandData = $h.CommandName | where-object { $_.text -notmatch "-TargetResource$" } | 
        ForEach-Object {
            Write-Verbose "Processing $($_.text)" 
            Try {
                $cmd = $_.Text
                $resolved = $cmd | get-command -ErrorAction Stop
                if ($resolved.CommandType -eq 'Alias') {
                    Write-Verbose "Resolving an alias"
                    #manually handle "?" because Get-Command and Get-Alias won't.
                    Write-Verbose "Detected the Where-Object alias '?'"
                    if ($cmd -eq '?') { 
                        Get-Command Where-Object
                    else {
                        $resolved.ResolvedCommandName | Get-Command
                else {
            Catch {
                Write-Verbose "Command is not recognized"
                #create a custom object for unknown commands
                    CommandType = "Unknown"
                    Name        = $cmd
                    ModuleName  = "Unknown"

        write-output $CommandData

    End {
        Write-Verbose -Message "Ending $($MyInvocation.Mycommand)"


This function was originally from Jeff Hicks .  I made a few tweaks, but the majority of this is his code.  As always, Jeff puts out amazing work.

Next, a simple script to call the function on all of the scripts in a certain directory:

if ($IsWindows -or $IsWindows -eq $null){$ModulesDir = (Get-ItemProperty HKLM:\SOFTWARE\PWSH).PowerShell_Modules}
else{get-content '/var/opt/tifa/settings.json'}
$log = $PSScriptRoot + '\'+ ($MyInvocation.MyCommand.Name).split('.')[0] + '.log'
$ModulesToImport = 'logging', 'SQL', 'PoshKeePass', 'PoshRSJob', 'SCOM', "OMI", 'DynamicMonitoring', 'Nix','Utils'
foreach ($module in $ModulesToImport) {Get-ChildItem $ModulesDir\$module\*.psd1 -Recurse | resolve-path | ForEach-Object { import-module $_.providerpath -force }}

$files = (Get-ChildItem 'D:\pwsh\' -Include *.ps1 -Recurse | where-object { $_.FullName -notmatch "\\modules*" }).fullname

[System.Collections.ArrayList]$AllData = @()
foreach ($file in $files) {
    [array]$data = Test-ScriptFile -Path $file
    foreach ($dataline in $data) {
        $path = $Dataline.module.path
        $version = $dataline.Module.version
        $dataobj = [PSCustomObject]@{
            File          = $File;
            Type          = $dataline.CommandType;
            Name          = $dataline.Name;
            ModuleName    = $dataline.ModuleName;
            ModulePath    = $path;
            ModuleVersion = $version;
$AllData|select-object -Property file, type, name, modulename,modulepath,moduleversion -Unique|out-gridview

There are a few gotchas you want to keep an eye out for – in order to correctly identify the cmdlets, you will need to load the module that contains said cmdlet.  You can see where I am loading several modules  – SCOM, SQL, logging, etc.  The modules in my script are loaded from modules stored in a reg key – HKLM:\Software\PWSH.  Load your modules in any way that works for you.  Also note that the last line sends the output to a gridview – change that output to something more useful unless you just previewing it.

And there you have it!  Thanks to Jeff for the core function, and I hope this helps keep your modules organized!

Powershell – Security in your profile

If you have done much with Invoke-webrequest, and if your endpoints have an inkling of security minded people watching them, then chances are you have run into a small issue:

Invoke-WebRequest : The request was aborted: Could not create SSL/TLS secure channel.

What’s happening here? Well, chances are that the end-point you are attempting to access has turned off TLS1.0 and 1.1, and for good reason! There is an easy fix, however. Just simply place a single line of code in your script above the invoke-webrequest:

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

Great! Post done, walk away.

But…..I have about 10000 scripts…..

That one line works great if you have just a handful of scripts that you run, but what if you need to do this for a large company – maybe a large enterprise? Well, it turns out that your profile can help.

First off – there are multiple PowerShell profiles on a system, but for this instance, let’s focus on the All-Users/All-Hosts profile (also sometimes referred to as the System profile). Depending on the flavor of PowerShell you are running – Microsoft vs Windows – the System profile will be in different locations. Not to fear, however, cause $PSHome will show you where the profile is located. Create your profile (if you haven’t already) in the $PSHome directory. The name of the file should be “profile.ps1”.

Now – place the Net.ServicePointManager line you would normally place in a single script into your System profile and save it. Whenever an invoke-webrequest is run from this system, it will automatically use the TLS1.2 protocol. Updating a few systems that run your scripts is a lot easier than updating thousands of scripts, and this will save you a ton of time.

SQL Process Automation with PowerShell

Here is a handy way to handle SQL processes that you find yourself needing to schedule. Of course you can always setup that kind scheduling via the SQL Server Agent, but there are two good reasons to do this kind of scheduling via PowerShell.

1: You don’t have rights to add jobs to via the SQL Server Agent. Some security teams will restrict non-dba access to either the agent or insist on setting the agent to a manual start.
2: You wish to have easier tracking, easier configuration, and just want to do something cool with PowerShell.

The other option you have when trying to schedule something like SQL processes would be to simply use Task Scheduler. Indeed – in my solution I actually use Task Scheduler as a base engine to run every minute or so. What I don’t like about Task Scheduler is trying to put SQL command lines in it. It’s flat out a pain. So, I built something that was easy to configure – even by someone who is not skilled in PowerShell, easy to implement, and has all of the typical good stuff you want with PowerShell.

The solution utilizes 3 main pieces. First, is a script that we will schedule to run every minute via Task Scheduler. Second, a configuration file in JSON format. I choose JSON since it’s simple to read and easy to write. Lastly, we will have XML file that tracks when the last time something ran. Let’s examine each piece:

The script file is fairly straight forward, and there are only a couple of pieces that need explaining. In simple terms this script file will be used as the engine that calls the various SQL commands we specify in the config.json file. We import a few modules, setup a couple of base variables, and then loop through the SQL commands, updating the runhistory.xml file with the timestamp. Schedule this file to run every minute via task scheduler.

$log = $PSScriptRoot + '\'+ ($MyInvocation.MyCommand.Name).split('.')[0] + '.log'
$ModulesDir = 'D:\pwsh\modules'
$ModulesToImport = 'DDTLogging','SQL'
foreach ($module in $ModulesToImport){Get-ChildItem $ModulesDir\$module\*.psd1 -Recurse | resolve-path | ForEach-Object { import-module $_.providerpath -force }}
$Date = Get-Date
$Commands = (get-content $PSScriptRoot\config.json|convertfrom-json).commands
[xml]$RunHistory = get-content "$PSScriptRoot\runhistory.xml"
foreach ($command in $Commands){
    $commandname = $
    $LastRunTime = ($runhistory.Catalog.dataset|where-object {$ -eq $commandname}|select-object -Property time).time
    if ($LastRunTime -lt $Date.AddMinutes(-$command.TimePeriod) -or $LastRunTime -eq $null)
        if ($LastRunTime -eq $null){
            $newdata = $RunHistory.Catalog.AppendChild($RunHistory.CreateElement("dataset"))
        else {
            $RunHistory.Catalog.dataset|where-object {$ -eq $commandname}|foreach {$_.time = [string]$date}
            invoke-sql -server $command.server -database $command.database -method $command.commandtype -integratedsecurity $true -statement $command.statement
            write-log -text "Error in $commandname.  $_" -level ERROR -log $log

If you are wondering about the Invoke-SQL command, it’s something that I wrapped up in a quick module. You can get the module here.

Now that we have the base script, let’s look at the config.json file. This is where the meat of the information about your commands come from:

            "statement":"exec refreshviews",
            "statement":"update cogsuppliers set time = getdate()",

As you can see – it’s a pretty straight forward. Put in the frequency you would like the statement to run (timeperiod), the statement itself, the server and database to run on, and finally the ‘type’ of command it is. This is just to tell the SQL module whether or not to load the data into a data table. That’s it! Anyone with a basic knowledge of how to write a json file can add or remove from this config file quickly!

The final piece is the runshistory.xml file. This simply lets the main script keep track of the last time each statement was run. You shouldn’t have to ever update this file manually.

  <dataset name="SQL_Views_Stored_Proc" time="11/15/2018 10:49:12" />
  <dataset name="Update_Time" time="11/15/2018 10:49:12" />

For full transparency, there are a few things I just need to swing back around and address. First – the commands runs sequentially. Long running SQL statements might cause others to fail or fall behind. The plan for that is to use something like PoshRSJob to run the jobs in parallel, and each in it’s own runspace. Secondly, there is a small chance that if someone was to manually edit the runhistory.xml file and remove one of the lines the script could error. I will update the script with a catch to make sure this doesn’t happen.

SCOM 1807, Linux omiagent service stopped, 403 error in discovery and more

I hope this post saves you some time and pain – I lost 2 days to troubleshooting and opening cases. Here is the setup:

OpsMgr 1807
Latest Linux/Unix MP (updated in August, 2018)
OEL 7.x client
Followed the instructions here: SCOM 1801/1807 Install

The agent install went fine – install completed, cert created, conf file created and configured, cert signed by the OpsMgr server and replaced on the client, and the agent restarted. That’s when I checked ‘scxadmin -status’. Omiserver was running, but omiagent was stopped. Only one log was created – omiserver.log, and nothing for the agent. Trying to start or restart via scxadmin yielded nothing. No feedback, no updates to logs, nothing. Even doing the install with –debug or settings the logs to verbose did nothing. So what happened?

Turns out, the omiagent process won’t start until a successful discovery is ran in the console. Who knew? Turns out that I didn’t. Two days lost trying to troubleshoot. I knew that a discovery was needed, but I assumed that the agent processes would be running ahead of time. Turns out they don’t all run before the discovery.

So, run over to the console and try to do the discovery only to immediately get a 403 error. Specifically, “The WinRM client received an HTTP status code of 403 from the remote WS-Management service.” Turns out this one is an easy fix, at least in my instance. My environment, like most in the corporate world, uses proxy servers. On the MS, a quick “netsh winhttp set proxy proxy-server=”http=” bypass-list=”*”” was all it took to fix the issue.

Once the discovery ran fine, it took about 5 minutes before the omiagent on the Linux machine was up and running on it’s own.

I hope this saves someone a few minutes of troubleshooting – if it does, shoot me a tweet!

New PowerShell Module – PoshMTLogging

At the end of this post, I promised a simple module for logging that can make use a mutex and has other neat features. Well, here it is!

This simple module will write to a log file. This module has a couple of unique features:

– Optional ‘UseMutex’ switch which helps avoid resource contention so multiple threads can write to the log at the same time
– Entry Severity make log readers like CMTrace color code automatically
– Standard line entry with automatic timestamping
– Automatic log rolling at 5mb

So check it out! Let me know what you think, and feel free to branch/pull with any ideas!

PowerShell Logging – What about file locking?

Today I was working on one of my large-scale enterprise automation scripts, when a common annoyance reared it’s ugly head. When dealing with multi-threaded applications, in this case Runspaces, it’s common to have one runspace trying to access a resource another runspace is currently using. For example – writing some output data to a log file. If two or more runspaces attempt to access the same log at the same time you will receive an error message. This isn’t a complete stoppage when dealing with log files, but if a critical resource is locked then your script could certainly fail.

So what is the easiest way to get around this? Enter the humble Mutex. There are several other posts that deal with Mutex locking, so I won’t go over the basics. Here I want to share some simple code that makes use of the mutex for writing to a log file.

The code below is a sample write-log function that takes 4 parameters. 3 of them are mandatory – Text for the log entry, name of the log to write to, and the ‘level’ of the entry. Level is really only used to help color coding and reading of the log in something like CMTrace. The last of the four parameters is ‘UseMutex’. This is what is going to tell our function whether or not to lock the resource being accessed.

        Simple function to write to a log file
        This function will write to a log file, pre-pending the date/time, level of detail, and supplied information
    .PARAMETER text
        This is the main text to log
    .PARAMETER Level
        Name of the log file to send the data to.
    .PARAMETER UseMutex
        A description of the UseMutex parameter.
        write-log -text "This is the main problem." -level ERROR -log c:\test.log
        Created by Donnie Taylor.
        Version 1.0     Date 4/5/2016
function Write-Log
        [Parameter(Mandatory = $true,
                   Position = 0)]
        [Parameter(Mandatory = $true,
                   Position = 1)]
        [ValidateSet('INFO', 'WARN', 'ERROR', 'DEBUG')]
        [Parameter(Mandatory = $true,
                   Position = 2)]
        [Parameter(Position = 3)]
    Write-Verbose "Log:  $log"
    $date = (get-date).ToString()
    if (Test-Path $log)
        if ((Get-Item $log).length -gt 5mb)
            $filenamedate = get-date -Format 'MM-dd-yy'
            $archivelog = ($log + '.' + $filenamedate + '.archive').Replace('/', '-')
            copy-item $log -Destination $archivelog
            Remove-Item $log -force
            Write-Verbose "Rolled the log."
    $line = $date + '---' + $level + '---' + $text
    if ($UseMutex)
        $LogMutex = New-Object System.Threading.Mutex($false, "LogMutex")
        $line | out-file -FilePath $log -Append
        $line | out-file -FilePath $log -Append

To write to the log, you use the function like such:

write-log -log c:\temp\output.txt -level INFO -text "This is a log entry" -UseMutex $true

Let’s test this. First, let’s make a script that will fail due to the file being in use. For this example, I am going to use PoshRSJob, which is a personal favorite of mine. I have saved the above function as a module to make sure I can access it from inside the Runspace. Run this script:

import-module C:\blog\PoshRSJob\PoshRSJob.psd1
$I = 1..3000
$I|start-rsjob -Throttle 250 -ScriptBlock{
    import-module C:\blog\write-log.psm1
    Write-Log -log c:\temp\mutex.txt  -level INFO -text $param

Assuming you saved your files in the same locations as mine, and this runs, then you should see something like this when you do a get-rsjob|receive-rsjob:

So what exactly happened here? Well, we told 3000 Runspaces to write their number ($param) to the log file….250 at a time (throttle). That’s obviously going to cause some contention. In fact, if we examine the output file (c:\temp\mutex.txt), and count the actual lines written to it, we will have missed a TON of log entries. On my PC, out of the 3000 that should write, we ended up with only 2813 entries. That is totally unacceptable to miss that many log entries. I’ve exaggerated the issue you will normally see using these large numbers, but this happens all the time when using smaller sets as well. To fix this, we are going to run the same bit of code, but we are going to use the ‘UseMutex’ option in write-log function. This tells each runspace to grab the mutex and attempt to write to the log. If it can’t grab the mutex, it will wait until it can (in this case forever – $LogMutex.WaitOne()|out-null). Run this code:

import-module C:\blog\PoshRSJob\PoshRSJob.psd1
$I = 1..3000
$I|start-rsjob -Throttle 250 -ScriptBlock{
    import-module C:\blog\write-log.psm1
    Write-Log -log c:\temp\mutex.txt  -level INFO -text $param -UseMutex $true

See the ‘-UseMutex’ switch? That should fix our problem. A get-rsjob|receive-rsjob now returns this:

Success! If we examine our output file, we find that all 3000 lines have been written. Using our new write-log function that uses a Mutex, we have solved our locking problem. Coming soon, I will publish the actual code on Github – stay tuned!