DSC - jasper-zanjani/Windows-Server GitHub Wiki
IaaS management of servers is possible with Desired State Configuration (DSC), a feature of Windows PowerShell where script files stored on a central server can apply specific a specific configuration to nodes. These scripts are idempotent, meaning that they can be applied repeatedly without generating errors.
The DSC model is composed of phases
- Authoring Phase, where MOF definitions are created
- Staging Phase, where declarative MOFs are staged and a Configuration calculated per node
- "Make It So" Phase, where declarative Configurations are implemented through imperative providers
Components of DSC scripts include:
- Local Configuration Manager: engine running on the client system that received configurations from the DSC server and applies them to the target.
- Node block specifies the names of target computers.
- Resource block specifies settings or components and the values that the configuration script should assign to them.
DSC configurations can be deployed in two different refresh modes
 |
 |
|---|---|
| Pull architecture: target LCM periodically retrieves configuration from a Pull Server, which consolidates MOF files. |
Push architecture: configuration is sent to target in response to explicit invocation of Start-DSCConfiguration on the server. |
LCM has to be configured to accept Configurations of either refresh mode.
PowerShell cmdlets for DSC are implemented in the psdesiredstateconfiguration module. Only a very few DSC cmdlets remain supported in PowerShell 7: these are marked below.
| Cmdlet | Description |
|---|---|
| New-DscCheckSum | Creates checksum files for DSC documents and DSC resources. |
| Get-DscConfiguration | Gets the current configuration of the nodes. |
| Publish-DscConfiguration | Publishes a DSC configuration to a set of computers. |
| Restore-DscConfiguration | Reapplies the previous configuration for the node. |
| Start-DscConfiguration | Apply configuration to nodes |
| Stop-DscConfiguration | Stops a running configuration. |
| Test-DscConfiguration | Tests whether the actual configuration on the nodes matches the desired configuration. |
| Update-DscConfiguration | Checks the pull server for an updated configuration and applies it. |
| Remove-DscConfigurationDocument 7 | Removes a configuration document from the DSC configuration store. |
| Get-DscConfigurationStatus | Retrieves data about completed configuration runs. |
| Disable-DscDebug | Stops debugging of DSC resources. |
| Enable-DscDebug | Starts debugging of all DSC resources. |
| Get-DscLocalConfigurationManager 7 | Gets LCM settings and states for the node. |
| Set-DscLocalConfigurationManager 7 | Applies LCM settings to nodes. |
| Get-DscResource | Gets the DSC resources present on the computer. |
| Invoke-DscResource | Runs a method of a specified DSC resource. |
Set LCM to push mode
[DSCLocalConfigurationManager()]
Configuration LCMConfig {
Node localhost {
Settings {
RefreshMode = 'Push'
}}}Install Telnet client
Configuration InstallTelnetLocal {
Import-DscResource -ModuleName 'PSDesiredStateConfiguration'
Node localhost {
WindowsOptionalFeature InstallTelnet {
Name = "Telnet-Client"
Ensure = "Present"
}}}Install WSL
Configuration InstallWSLLocal {
Import-DscResource -ModuleName 'PSDesiredStateConfiguration'
Node localhost {
WindowsOptionalFeature InstallWSL {
Name = "Microsoft-Windows-Subsystem-Linux"
Ensure = "Present"
}}}