How to skip resources if it doesnt exist but do no trigger an error

[dummys]

Hi,
I'm using DSC to configure multiple computer that can have Windows 10/11 with/without certain services.
I was using DSC 2.0 to do it with the following code:

if (Get-Service "AJRouter" -ErrorAction SilentlyContinue ) {
            Service SvcAJRouter {
                Name   = "AJRouter"
                State = "Stopped"
                StartupType = "Disabled"
            }
        }

I tried to implement it in DSC 3.0 for for now I can't make it work, here is my resources.yaml:

$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
resources:
  - name: Use Windows powershell to configure services
    type: Microsoft.Windows/WindowsPowerShell
    properties:
      resources:
        - name: CheckAndDisableAJRouter
          type: PSDesiredStateConfiguration/Service
          properties:
            name: AJRouter
            state: Stopped
            startupType: Disabled
            condition: 
              type: PSDesiredStateConfiguration/Service
              properties:
                name: AJRouter

And I apply with: dsc config set --file resources.yaml but I get the following error:

Message        : Failed to serialize properties into CimInstance.
Data           : {}
InnerException :
TargetSite     : Microsoft.Management.Infrastructure.CimInstance SerializeIntoCimInstance(System.Management.Automation.Language.DynamicKeyword,
                 Microsoft.PowerShell.Commands.ModuleSpecification, System.Collections.Hashtable)
StackTrace     :    at Microsoft.PowerShell.DesiredStateConfiguration.Commands.InvokeDscResourceMethodCommand.SerializeIntoCimInstance(DynamicKeyword resourceInfo, ModuleSpecification
                 moduleSpecification, Hashtable property)
                    at Microsoft.PowerShell.DesiredStateConfiguration.Commands.InvokeDscResourceMethodCommand.CreateParametersCollection()
                    at Microsoft.PowerShell.DesiredStateConfiguration.Commands.InvokeDscResourceMethodCommand.ProcessRecord()
                    at System.Management.Automation.CommandProcessor.ProcessRecord()
HelpLink       :
Source         : Microsoft.Windows.DSC.CoreConfProviders
HResult        : -2146233076




2025-04-14T13:04:13.233521Z ERROR dsc_lib::dscresources::command_resource: 874: PID 2100: Exception: Failed to serialize properties into CimInstance.
2025-04-14T13:04:13.234311Z DEBUG dsc_lib::dscresources::command_resource: 648: Process 'powershell' id 2100 exited with code 1
2025-04-14T13:04:13.234885Z ERROR dsc::subcommand: 103: Error: Command: Resource 'powershell' [exit code 1] manifest description: Error

[Gijsreyn]

Hey @dummys, what you're looking for is Microsoft.DSC/Assertion, which performs a test before applying the actual configuration. I couldn't fully test this example, but you should be able to do something like:

$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
resources:
- name: Stop service
  type: PSDesiredStateConfiguration/Service
  properties:
    name: AJRouter
    state: Stopped
    startupType: Disabled
  dependsOn:
  - "[resourceId('Microsoft.DSC/Assertion','Assert service present')]"
- name: Assert service present
  type: Microsoft.DSC/Assertion
  properties:
    $schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
    resources:
    - name: AJRouter
      type: PSDesiredStateConfiguration/Service
      properties:
        name: AJRouter

Do note, it is using the new syntax only available from preview.2 versions onwards for declaring adapter resources. Let me know if that works!

[dummys]

Hello,

The problem with assertion, is that if it failed, it stop the execution. In my case I want to continue because it is possible that such services doesn't exist in Windows 11 and exist in Windows 10

[Gijsreyn]

Probably using Microsoft.DSC/Group will solve that issue.