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Part 2: Use VSAE fragments to dynamically discover an application based on the existence of a registry key or value

This is Part 2 in a series of posts described here:  https://kevinholman.com/2016/06/04/authoring-management-packs-the-fast-and-easy-way-using-visual-studio/

 

Now we will start with our first example fragment – discovering an app and creating a class for it.

 

Step 1:  Download and extract the sample MP fragments.  These are available here:  https://gallery.technet.microsoft.com/SCOM-Management-Pack-VSAE-2c506737

I will update these often as I enhance and add new ones, so check back often for new versions.

 

Step 2:  Open your newly created MP solution, and open Solution Explorer.

We want to keep things organized – so we want to create folders to organize our solution as we go.  This wont affect anything in the MP XML, it just keeps the solution organized.

Right click “Fab.DemoApp” and choose Add > New Folder

 

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Name the folder “Classes”

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Step 3:  Add the class fragment:  Right click “Classes” and choose Add > Existing Item.

 

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Browse to where you extracted my sample fragments, and choose the Class.And.Discovery.Registry.KeyExists.mpx.

Select this fragment which now shows up under classes in solution explorer, and you should see the XML pop up in Visual Studio.

 

Step 4:  Find and Replace!

This is the area where I tried to make using Visual Studio and VSAE MUCH easier.  I came up with a standard item list that you will need to commonly replace in your XML, and enclosed each item with “##” to make them easy to find.  I also included notes at the top of each fragment, explaining what the fragment does, and what you need to replace.

This allows you to create LOTS of monitoring ins SECONDS, simply using Find and Replace.

For this example, we need to replace ##CompanyID##, ##AppName##, ##RegKeyPath##

CompanyID is easy – for my demo’s that’s my company abbreviation, or “Fab”.

AppName in this case, is a fake application I called “DemoApp”

RegKeyPath is simply going to be the path in the registry which designates that “DemoApp” is installed.

 

I start with replacing ##CompanyID## with “Fab”

Edit > Find and Replace > Quick Replace

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There is a “Replace All” button at the red arrow above.

 

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Now I repeat this for ##AppName##

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And lastly – the ##RegKeyPath##

 

My Registry Key for this app is HKEY_LOCAL_MACHINE\SOFTWARE\DemoApp

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However, in SCOM “HKEY_LOCAL_MACHINE” is already hard coded

So all I need to do is replace ##RegKeyPath## with “SOFTWARE\DemoApp”

 

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Done!

Three quick find/replace actions, and we have a working class definition, with a registry discovery.  Look through the XML to familiarize yourself with all that you just created.  There is a TypeDefinitions section with your Class definition, along with a Discovery to discover all machines with the registry key.

**Note – if your reg key is not present in “SOFTWARE” but you want to use something in “SYSTEM” such as a service in SYSTEM\CurrentControlSet\Services\, you could simply change the path in the fragment.

 

 

Step 5:  Build the MP.  Then import it as a test.

Open Discovered Inventory in the SCOM console – Change Target type – and find the class you just created

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After a few minutes, the agents should download this MP, run the discovery, and any agents with that registry key will show up as an instance of our new class:

 

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Congrats!  You have dynamically discovered all computers with the “DemoApp” application in your company.  Start to finish, about 1 minute.  5 minutes tops if you are learning VSAE for the first time.

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