Added Datadog extension info

Author: Ryan Willis

articles/azure-arc/servers/manage-vm-extensions-cli.md

@@ -53,6 +53,12 @@ The following example enables the Microsoft Antimalware extension on an Azure Ar
 az connectedmachine extension create --resource-group "resourceGroupName" --machine-name "myMachineName" --location "regionName" --publisher "Microsoft.Azure.Security" --type "IaaSAntimalware" --name "IaaSAntimalware" --settings '"{\"AntimalwareEnabled\": \"true\"}"'
 ```
 
+The following example enables the Datadog extension on an Azure Arc-enabled Windows server:
+
+```azurecli
+az connectedmachine extension create --resource-group "resourceGroupName" --machine-name "myMachineName" --location "regionName" --publisher "Datadog.Agent" --type "DatadogWindowsAgent" --settings '{"site": "us3.datadoghq.com"}' --protected-settings '{"api_key": "YourDatadogAPIKey" }'
+```
+
 ## List extensions installed
 
 To get a list of the VM extensions on your Azure Arc-enabled server, use [az connectedmachine extension list](/cli/azure/connectedmachine/extension#az-connectedmachine-extension-list) with the `--machine-name` and `--resource-group` parameters.

articles/azure-arc/servers/manage-vm-extensions-powershell.md

@@ -86,6 +86,27 @@ The following example enables the Key Vault VM extension on an Azure Arc-enabled
     New-AzConnectedMachineExtension -ResourceGroupName $resourceGroup -Location $location -MachineName $machineName -Name "KeyVaultForWindows or KeyVaultforLinux" -Publisher "Microsoft.Azure.KeyVault" -ExtensionType "KeyVaultforWindows or KeyVaultforLinux" -Setting $settings
 ```
 
+### Datadog VM extension
+
+The following example enables the Datadog VM extension on an Azure Arc-enabled server:
+
+```azurepowershell
+$resourceGroup = "resourceGroupName"
+$machineName = "machineName"
+$location = "machineRegion"
+$osType = "Windows" # change to Linux if appropriate
+$settings = @{
+    # change to your preferred Datadog site
+    site = "us3.datadoghq.com"
+}
+$protectedSettings = @{
+    # change to your Datadog API key
+    api_key = "APIKEY"
+}
+
+New-AzConnectedMachineExtension -ResourceGroupName $resourceGroup -Location $location -MachineName $machineName -Name "Datadog$($osType)Agent" -Publisher "Datadog.Agent" -ExtensionType "Datadog$($osType)Agent" -Setting $settings -ProtectedSetting $protectedSettings
+```
+
 ## List extensions installed
 
 To get a list of the VM extensions on your Azure Arc-enabled server, use [Get-AzConnectedMachineExtension](/powershell/module/az.connectedmachine/get-azconnectedmachineextension) with the `-MachineName` and `-ResourceGroupName` parameters.