Note on how to query os version and define policy

Author: deeikele

articles/machine-learning/how-to-create-manage-compute-instance.md

@@ -673,9 +673,71 @@ To create a compute instance, you'll need permissions for the following actions:
 * *Microsoft.MachineLearningServices/workspaces/computes/write*
 * *Microsoft.MachineLearningServices/workspaces/checkComputeNameAvailability/action*
 
+### Audit and observe compute instance version (preview)
+
+# [Python SDK](#tab/python)
+
+[!INCLUDE [sdk v2](../../includes/machine-learning-sdk-v2.md)]
+
+```python
+from azure.ai.ml.entities import ComputeInstance, AmlCompute
+
+# Display operating system version
+instance = ml_client.compute.get("myci")
+print instance.os_image_metadata
+```
+
+For more information on the classes, methods, and parameters used in this example, see the following reference documents:
+
+* [`AmlCompute` class](/python/api/azure-ai-ml/azure.ai.ml.entities.amlcompute)
+* [`ComputeInstance` class](/python/api/azure-ai-ml/azure.ai.ml.entities.computeinstance)
+
+# [Azure CLI](#tab/azure-cli)
+
+[!INCLUDE [cli v2](../../includes/machine-learning-cli-v2.md)]
+
+```azurecli
+az ml compute show --name "myci"
+```
+
+# [Studio](#tab/azure-studio)
+
+In your workspace in Azure Machine Learning studio, select Compute, then select compute instance on the top. Select a compute instance's compute name to see its properties including the current operating system. When a more recent instance OS version is, use the creation wizard to create a new instance.
+
+---
+
+Administrators can use [Azure Policy](./../governance/policy/overview.md) definitions to audit instances that are running on outdated operating system versions. The following is a sample policy:
+
+```json
+{
+    "mode": "All",
+    "policyRule": {
+      "if": {
+        "allOf": [
+          {
+            "field": "type",
+            "equals": "Microsoft.MachineLearningServices/workspaces/computes"
+          },
+          {
+            "field": "Microsoft.MachineLearningServices/workspaces/computes/computeType",
+            "equals": "ComputeInstance"
+          },
+          {
+            "field": "Microsoft.MachineLearningServices/workspaces/computes/osImageMetadata.isLatestOsImageVersion",
+            "equals": "false"
+          }
+        ]
+      },
+      "then": {
+        "effect": "Audit"
+      }
+    }
+}    
+```
+
 ## Next steps
 
 * [Access the compute instance terminal](how-to-access-terminal.md)
 * [Create and manage files](how-to-manage-files.md)
 * [Update the compute instance to the latest VM image](concept-vulnerability-management.md#compute-instance)
-* [Submit a training job](v1/how-to-set-up-training-targets.md)
+* [Submit a training job](v1/how-to-set-up-training-targets.md)