Quickstart: Create a policy assignment to identify non-compliant resources

The first step in understanding compliance in Azure is to identify the status of your resources. This quickstart steps you through the process of creating a policy assignment to identify virtual machines that aren't using managed disks.

At the end of this process, you'll successfully identify virtual machines that aren't using managed disks. They're non-compliant with the policy assignment.

Prerequisites

If you don't have an Azure subscription, create a free account before you begin.

Create a policy assignment

In this quickstart, you create a policy assignment and assign the Audit VMs that do not use managed disks policy definition.

  1. Launch the Azure Policy service in the Azure portal by selecting All services, then searching for and selecting Policy.

    Screenshot of searching for Policy in All Services.

  2. Select Assignments on the left side of the Azure Policy page. An assignment is a policy that has been assigned to take place within a specific scope.

    Screenshot of selecting the Assignments page from Policy Overview page.

  3. Select Assign Policy from the top of the Policy - Assignments page.

    Screenshot of selecting 'Assign policy' from Assignments page.

  4. On the Assign Policy page, set the Scope by selecting the ellipsis and then selecting either a management group or subscription. Optionally, select a resource group. A scope determines what resources or grouping of resources the policy assignment gets enforced on. Then use the Select button at the bottom of the Scope page.

    This example uses the Contoso subscription. Your subscription will differ.

  5. Resources can be excluded based on the Scope. Exclusions start at one level lower than the level of the Scope. Exclusions are optional, so leave it blank for now.

  6. Select the Policy definition ellipsis to open the list of available definitions. Azure Policy comes with built-in policy definitions you can use. Many are available, such as:

    • Enforce tag and its value
    • Apply tag and its value
    • Inherit a tag from the resource group if missing

    For a partial list of available built-in policies, see Azure Policy samples.

  7. Search through the policy definitions list to find the Audit VMs that do not use managed disks definition. Select that policy and then use the Select button.

    Screenshot of filtering the available definitions.

  8. The Assignment name is automatically populated with the policy name you selected, but you can change it. For this example, leave Audit VMs that do not use managed disks. You can also add an optional Description. The description provides details about this policy assignment. Assigned by will automatically fill based on who is logged in. This field is optional, so custom values can be entered.

  9. Leave policy enforcement Enabled. For more information, see Policy assignment - enforcement mode.

  10. Select Next at the bottom of the page or the Parameters tab at the top of the page to move to the next segment of the assignment wizard.

  11. If the policy definition selected on the Basics tab included parameters, they are configured on this tab. Since the Audit VMs that do not use managed disks has no parameters, select Next at the bottom of the page or the Remediation tab at the top of the page to move to the next segment of the assignment wizard.

  12. Leave Create a Managed Identity unchecked. This box must be checked when the policy or initiative includes a policy with either the deployIfNotExists or modify effect. As the policy used for this quickstart doesn't, leave it blank. For more information, see managed identities and how remediation security works.

  13. Select Next at the bottom of the page or the Non-compliance messages tab at the top of the page to move to the next segment of the assignment wizard.

  14. Set the Non-compliance message to Virtual machines should use a managed disk. This custom message is displayed when a resource is denied or for non-compliant resources during regular evaluation.

  15. Select Next at the bottom of the page or the Review + Create tab at the top of the page to move to the next segment of the assignment wizard.

  16. Review the selected options, then select Create at the bottom of the page.

You're now ready to identify non-compliant resources to understand the compliance state of your environment.

Identify non-compliant resources

Select Compliance in the left side of the page. Then locate the Audit VMs that do not use managed disks policy assignment you created.

Screenshot of compliance details on the Policy Compliance page.

If there are any existing resources that aren't compliant with this new assignment, they appear under Non-compliant resources.

When a condition is evaluated against your existing resources and found true, then those resources are marked as non-compliant with the policy. The following table shows how different policy effects work with the condition evaluation for the resulting compliance state. Although you don't see the evaluation logic in the Azure portal, the compliance state results are shown. The compliance state result is either compliant or non-compliant.

Resource State Effect Policy Evaluation Compliance State
New or Updated Audit, Modify, AuditIfNotExist True Non-Compliant
New or Updated Audit, Modify, AuditIfNotExist False Compliant
Exists Deny, Audit, Append, Modify, DeployIfNotExist, AuditIfNotExist True Non-Compliant
Exists Deny, Audit, Append, Modify, DeployIfNotExist, AuditIfNotExist False Compliant

Note

The DeployIfNotExist and AuditIfNotExist effects require the IF statement to be TRUE and the existence condition to be FALSE to be non-compliant. When TRUE, the IF condition triggers evaluation of the existence condition for the related resources.

Clean up resources

To remove the assignment created, follow these steps:

  1. Select Compliance (or Assignments) in the left side of the Azure Policy page and locate the Audit VMs that do not use managed disks policy assignment you created.

  2. Right-click the Audit VMs that do not use managed disks policy assignment and select Delete assignment.

    Screenshot of using the context menu to delete an assignment from the Compliance page.

Next steps

In this quickstart, you assigned a policy definition to a scope and evaluated its compliance report. The policy definition validates that all the resources in the scope are compliant and identifies which ones aren't.

To learn more about assigning policies to validate that new resources are compliant, continue to the tutorial for: