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Azure Policy Authoring Guide

This reference implementation uses Built-In and Custom Policies to provide guardrails in the Azure environment. The goal of this authoring guide is to provide step-by-step instructions to manage and customize policy definitions and assignments that align with your organization's compliance requirements.

Table of Contents

Existing configuration

Built-in policy assignments

Built-in policy set assignment templates are located in /policy/builtin/assignments directory.

Policy Set Description Deployment Template Configuration
Canada Federal PBMM This initiative includes audit and virtual machine extension deployment policies that address a subset of Canada Federal PBMM controls. pbmm.bicep pbmm.parameters.json
NIST SP 800-53 Revision 4 This initiative includes policies that address a subset of NIST SP 800-53 Rev. 4 controls. nist80053r4.bicep nist80053r4.parameters.json
NIST SP 800-53 Revision 5 This initiative includes policies that address a subset of NIST SP 800-53 Rev. 5 controls. nist80053r5.bicep nist80053r5.parameters.json
Azure Security Benchmark The Azure Security Benchmark initiative represents the policies and controls implementing security recommendations defined in Azure Security Benchmark, see https://aka.ms/azsecbm. This also serves as the Microsoft Defender for Cloud default policy initiative. asb.bicep asb.parameters.json
CIS Microsoft Azure Foundations Benchmark 1.3.0 This initiative includes policies that address a subset of CIS Microsoft Azure Foundations Benchmark recommendations. cis-msft-130.bicep cis-msft-130.parameters.json
FedRAMP Moderate This initiative includes policies that address a subset of FedRAMP Moderate controls. fedramp-moderate.bicep fedramp-moderate.parameters.json
HIPAA / HITRUST 9.2 This initiative includes audit and virtual machine extension deployment policies that address a subset of HITRUST/HIPAA controls. hitrust-hipaa.bicep hitrust-hipaa.parameters.json
Location Restrict deployments to Canadian regions. location.bicep location.parameters.json

Custom policy set definitions and assignments

Custom policy set definition templates are located in /policy/custom/definitions/policyset directory.

Custom policy set assignment templates are located in /policy/custom/assignments directory.

Policy Set Description Policy set definition deployment template Configuration
Azure Kubernetes Service Azure Policy Add-on to Azure Kubernetes Service clusters & Pod Security. AKS.bicep AKS.parameters.json
Microsoft Defender for Cloud Configures Microsoft Defender for Cloud, including Azure Defender for subscription and resources. DefenderForCloud.bicep DefenderForCloud.parameters.json
Private DNS Zones for Private Endpoints Policies to configure DNS zone records for private endpoints. Policy set is assigned through deployment pipeline when private endpoint DNS zones are managed in the Hub Network. DNSPrivateEndpoints.bicep DNSPrivateEndpoints.parameters.json
Log Analytics for Azure Services (IaaS and PaaS) Configures monitoring agents for IaaS and diagnostic settings for PaaS to send logs to a central Log Analytics Workspace. LogAnalytics.bicep LogAnalytics.parameters.json
Networking Configures policies for network resources. Network.bicep Network.parameters.json
Tag Governance Configures required tags and tag propagation from resource groups to resources. Tags.bicep Tags.parameters.json

Built-in policy sets

The built-in policy sets are used as-is to ensure future improvements from Azure Engineering teams are automatically incorporated into the Azure environment.

New built-in policy set assignment

Steps

We will not be assigning the policy through Azure Portal, but use these steps to identify the necessary info, such as name, definition ID, permissions, and parameters, which are required for the Policy Assignment.

Step 1: Collect information

  1. Navigate to Azure Portal -> Azure Policy -> Definitions

  2. Open the Built-In Policy Set (it is also called an Initiative) that will be assigned through automation. For example: Canada Federal PBMM

    Collect the following information:

    • Name (e.g. Canada Federal PBMM)
    • Definition ID (e.g. /providers/Microsoft.Authorization/policySetDefinitions/4c4a5f27-de81-430b-b4e5-9cbd50595a87)

  3. Click the Assign button and select a scope for the assignment. We will not be assigning the policy through Azure Portal, but use this step to identify the permissions required for the Policy Assignment.

    Collect the following information from the Remediation tab:

    • Permissions - required when there are auto remediation policies. You may see zero, one (e.g. Contributor) or many comma-separated (e.g. Log Analytics Contributor, Virtual Machine Contributor, Monitoring Contributor) roles listed. Permissions will not be listed when none are required for the policy assignment to function.

    Once the permissions are identified, click the Cancel button to discard the changes.

    Use Azure Built-In Roles table to map the permission name to it's Resource ID. Resource ID will be used when defining the role assignments.

  4. Click on the Duplicate initiative button. We will not be duplicating the policy set definition, but use this step to identify the parameter names that will need to be populated during policy assignment.

    Collect the following information from the Initiative parameters tab:

    • Parameters (e.g. logAnalytics, logAnalyticsWorkspaceId, listOfResourceTypesToAuditDiagnosticSettings). You may see zero, one or many parameters listed. It is possible that a policy set doesn't have any parameters.

Step 2: Create Bicep template & parameters JSON file

  1. Navigate to policy/builtin/assignments directory and create two files. Replace POLICY_ASSIGNMENT with the name of your assignment such as pbmm.

    • POLICY_ASSIGNMENT.bicep (i.e. pbmm.bicep) - this file defines the policy assignment deployment
    • POLICY_ASSIGNMENT.parameters.json (i.e. pbmm.parameters.json) - this file defines the parameters used to deploy the policy assignment.

  2. Edit the Bicep file to include the following template. This template can be customized as required. Pre-requisites are:

    • targetScope must be managementGroup
    • parameter policyAssignmentManagementGroupId must be defined. It is used to set the policy assignment through automation.

    Sample Template

      targetScope = 'managementGroup'

  @description('Management Group scope for the policy assignment.')
  param policyAssignmentManagementGroupId string

  @allowed([
    'Default'
    'DoNotEnforce'
  ])
  @description('Policy set assignment enforcement mode.  Possible values are { Default, DoNotEnforce }.  Default value:  Default')
  param enforcementMode string = 'Default'

  // Start - Any custom parameters required for your policy assignment
  param ...
  // End - Any custom parameters required for your policy assignment

  // Add the GUID from the Definition ID that was gathered above
  var policyId = '<< GUID >>'

  // Add the policy set assignment name (i.e. the name of the Policy Set Name)
  var assignmentName = '<< POLICY ASSIGNMENT NAME >>'

  var scope = tenantResourceId('Microsoft.Management/managementGroups', policyAssignmentManagementGroupId)
  var policyScopedId = resourceId('Microsoft.Authorization/policySetDefinitions', policyId)

  resource policySetAssignment 'Microsoft.Authorization/policyAssignments@2020-03-01' = {

    // Set the name of the policy assignment
    // Example: name: 'pbmm-${uniqueString('pbmm-',policyAssignmentManagementGroupId)}'

    name: '<< NAME >>'

    properties: {
      displayName: assignmentName
      policyDefinitionId: policyScopedId
      scope: scope
      notScopes: [
      ]
      parameters: {
        // Add any parameters identified earlier into this section
      }

      // The policy assignment enforcement mode. Possible values are Default and DoNotEnforce.
      enforcementMode: enforcementMode
    }
    identity: {
      type: 'SystemAssigned'
    }
    location: deployment().location
  }

  // These role assignments are required to allow Policy Assignment to remediate.
  // Add this section only when there are permissions to assign to the policy set.
  // Ensure that the name is a GUID and generated with a deterministic formula such as the example below.
  // Set the role definition id based on the information gathered earlier.
  resource policySetRoleAssignmentContributor 'Microsoft.Authorization/roleAssignments@2020-04-01-preview' = {
    name: guid(policyAssignmentManagementGroupId, 'pbmm-Contributor')
    scope: managementGroup()
    properties: {
      roleDefinitionId: '/providers/Microsoft.Authorization/roleDefinitions/b24988ac-6180-42a0-ab88-20f7382dd24c'
      principalId: policySetAssignment.identity.principalId
      principalType: 'ServicePrincipal'
    }
  }

    Example: PBMM Policy Set Assignment

      targetScope = 'managementGroup'

  @description('Management Group scope for the policy assignment.')
  param policyAssignmentManagementGroupId string

  @allowed([
    'Default'
    'DoNotEnforce'
  ])
  @description('Policy set assignment enforcement mode.  Possible values are { Default, DoNotEnforce }.  Default value:  Default')
  param enforcementMode string = 'Default'

  @description('Log Analytics Resource Id to integrate Microsoft Defender for Cloud.')
  param logAnalyticsWorkspaceId string

  @description('List of members that should be excluded from Windows VM Administrator Group.')
  param listOfMembersToExcludeFromWindowsVMAdministratorsGroup string

  @description('List of members that should be included in Windows VM Administrator Group.')
  param listOfMembersToIncludeInWindowsVMAdministratorsGroup string

  var policyId = '4c4a5f27-de81-430b-b4e5-9cbd50595a87' // Canada Federal PBMM
  var assignmentName = 'Canada Federal PBMM'

  var scope = tenantResourceId('Microsoft.Management/managementGroups', policyAssignmentManagementGroupId)
  var policyScopedId = resourceId('Microsoft.Authorization/policySetDefinitions', policyId)

  resource policySetAssignment 'Microsoft.Authorization/policyAssignments@2020-03-01' = {
    name: 'pbmm-${uniqueString('pbmm-',policyAssignmentManagementGroupId)}'
    properties: {
      displayName: assignmentName
      policyDefinitionId: policyScopedId
      scope: scope
      notScopes: [
      ]
      parameters: {
        logAnalyticsWorkspaceIdforVMReporting: {
          value: logAnalyticsWorkspaceId
        }
        listOfMembersToExcludeFromWindowsVMAdministratorsGroup: {
          value: listOfMembersToExcludeFromWindowsVMAdministratorsGroup
        }
        listOfMembersToIncludeInWindowsVMAdministratorsGroup: {
          value: listOfMembersToIncludeInWindowsVMAdministratorsGroup
        }
      }
      enforcementMode: enforcementMode
    }
    identity: {
      type: 'SystemAssigned'
    }
    location: deployment().location
  }

  // These role assignments are required to allow Policy Assignment to remediate.
  resource policySetRoleAssignmentContributor 'Microsoft.Authorization/roleAssignments@2020-04-01-preview' = {
    name: guid(policyAssignmentManagementGroupId, 'pbmm-Contributor')
    scope: managementGroup()
    properties: {
      roleDefinitionId: '/providers/Microsoft.Authorization/roleDefinitions/b24988ac-6180-42a0-ab88-20f7382dd24c'
      principalId: policySetAssignment.identity.principalId
      principalType: 'ServicePrincipal'
    }
  }

  3. Edit the JSON parameters file to define the input parameters for the Bicep template. This parameters JSON file is used by Azure Resource Manager (ARM) for runtime inputs.

    You can use any of the templated parameters to set values based on environment configuration or hard code them as needed.

    Sample Template

    {
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "policyAssignmentManagementGroupId": {
            "value": "{{var-policyAssignmentManagementGroupId}}"
        },
        "enforcementMode": {
            "value": "Default"
        },
        "EXTRA_POLICY_ASSIGNMENT_PARAMETER_NAME_1": {
            "value": "EXTRA_POLICY_ASSIGNMENT_PARAMETER_VALUE_1"
        },
        "EXTRA_POLICY_ASSIGNMENT_PARAMETER_NAME_2": {
            "value": "EXTRA_POLICY_ASSIGNMENT_PARAMETER_VALUE_2"
        }
    }
}

    Example: PBMM Policy Set Parameters

    {
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "policyAssignmentManagementGroupId": {
            "value": "{{var-policyAssignmentManagementGroupId}}"
        },
        "enforcementMode": {
            "value": "Default"
        },
        "logAnalyticsWorkspaceId": {
            "value": "{{var-logging-logAnalyticsWorkspaceId}}"
        },
        "listOfMembersToExcludeFromWindowsVMAdministratorsGroup": {
            "value": "__tbd__implementation_specific__"
        },
        "listOfMembersToIncludeInWindowsVMAdministratorsGroup": {
            "value": "__tbd__implementation_specific__"
        }
    }
}

Step 3: Update Azure DevOps Pipeline

  • Edit /.pipelines/policy.yml
  • Navigate to the BuiltInPolicyJob Job definition
  • Navigate to the Assign Policy Set Step definition
  • Add the policy assignment file name (without extension) to the deployTemplates array parameter

Step 4: Deploy built-in policy set assignment

Execute Azure DevOps Policy pipeline to deploy. The policy set assignment will be deployed to the top level management group (i.e. pubsec).

It takes approximately 30 minutes for the assignment to be applied to the defined scope. Once it's applied, the evaluation cycle begins for resources within that scope against the newly assigned policy or initiative, and depending on the effects defined by the policy or initiative, resources are marked as compliant, non-compliant, or exempt. A large policy or initiative evaluated against a large scope of resources can take time. As such, there's no pre-defined expectation of when the evaluation cycle completes. Once evaluation completes, the updated compliance results are available in the portal and to SDKs. See Azure Docs for more information.

Step 5: Verify policy set assignment

  • You can navigate to Azure Policy Compliance to verify in Azure Portal.

  • If there are deployment errors:

    • Navigate to Management Groups in Azure Portal
    • Select the top level management group (i.e. pubsec)
    • Select Deployments
    • Review the deployment errors

Remove built-in policy set assignment

Automation does not remove an existing policy set assignment. Removing the policy set assignment from the Azure DevOps pipeline ensures that it's no longer created. Any existing policy set assignments must be deleted manually.

Steps

Step 1: Remove built-in policy set assignment from Azure DevOps Pipeline

  • Edit /.pipelines/policy.yml
  • Navigate to the BuiltInPolicyJob Job definition
  • Navigate to the Assign Policy Set Step definition
  • Remove the policy set assignment from the deployTemplates array parameter

Step 2: Remove built-in policy set assignment's IAM assignments

  • Navigate to Azure Policy Assignments in Azure Portal
    • Find the policy set assignment
    • Click on the ... beside the policy set assignment and select Delete assignment
  • Navigate to Management Groups in Azure Portal
    • Select the top level management group (i.e. pubsec)
    • Select Access control (IAM)
    • Select Role Assignments
    • Use the Type filter to find any Unknown role assignments and delete them. This step is required since deleting the policy set assignment does not automatically remove any role assignments. When the policy set assignment is removed, it's managed identity is also removed thus marking these role assignments as Unknown.

Enable or disable built-in policy set enforcement

You may want to evaluate the compliance in your environment without any automatic remediation, either through DeployIfNotExists or modify policies. To support this scenario, all policy set assignments support an enforcementMode setting. This can be set to either: Default or DoNotEnforce:

  • Default = enable policy set enforcement
  • DoNotEnforce = disable policy set enforcement

Please review guidance and expected behaviour of these settings prior to making any modification:

You can switch between these modes per-policy set based on your Azure Policy adoption strategy.

To manage this setting:

  • Navigate to policy/builtin/assignments
  • Open *.parameters.json. There is 1 parameters file per policy set assignment
  • Modify enforcementMode parameter with either Default or DoNotEnforce
  • Re-run the policy-ci Azure DevOps pipeline to update Azure

Custom policies

Custom policies and policy sets enable an organization to expand their governance in Azure. Prior to creating any custom policies, we recommend searching for a suitable built-in policy through Azure Policy Definitions. You can create custom policy sets that contain built-in and custom policies.

New custom policy definition

We recommend organizing the custom policies into a custom policy sets and assigned as a unit. This approach will reduce the management overhead and complexity in the future. You can have as many custom policy sets as required.

Steps

Step 1: Create policy definition template

  1. Create a subdirectory in policy/custom/definitions/policy directory. Each policy is organized into it's own directory. The directory name must not have any spaces nor special characters.

  2. Create 3 files in the newly created directory:

    • azurepolicy.config.json - metadata used by Azure DevOps Pipeline to configure the policy.
    • azurepolicy.parameters.json - contains parameters used in the policy.
    • azurepolicy.rules.json - the policy rule definition.

  3. Edit azurepolicy.config.json.

    Information from this file is used as part of deploying Azure Policy definition.

    Example

    {
  "name": "Audit diagnostic setting - Logs",
  "mode": "all"
}

    The mode determines which resource types are evaluated for a policy definition. The supported modes are:

    • all: evaluate resource groups, subscriptions, and all resource types
    • indexed: only evaluate resource types that support tags and location

    See Azure Policy Reference for more information.

  4. Edit azurepolicy.parameters.json.

    Define parameters that are required by the policy definition. Using parameters enable the policy to be used with different configuration.

    See Azure Parameter Reference for more information.

    Example

    {
  "listOfResourceTypes": {
    "type": "Array",
    "metadata": {
      "displayName": "Resource Types",
      "description": null,
      "strongType": "resourceTypes"
    }
  }
}

  5. Edit azurepolicy.rules.json

    Describes the policy rule that will be evaluated by Azure Policy. The rule can have any effect such as Audit, Deny, DeployIfNotExists.

    See Azure Policy docs for more information on creating custom policies.

    Example

    {
  "if": {
    "field": "type",
    "in": "[parameters('listOfResourceTypes')]"
  },
  "then": {
    "effect": "AuditIfNotExists",
    "details": {
      "type": "Microsoft.Insights/diagnosticSettings",
      "existenceCondition": {
        "allOf": [
          {
            "field": "Microsoft.Insights/diagnosticSettings/logs.enabled",
            "equals": "true"
          }
        ]
      }
    }
  }
}

Step 2: Deploy policy definition template

Execute Azure DevOps Policy pipeline to deploy. The policy definition will be deployed to the top level management group (i.e. pubsec).

Deploying the policy definition does not put it in effect. You must either create a new custom policy set or update an existing custom policy set to put it in effect.

Step 3: Verify policy definition deployment

Navigate to Azure Policy Definitions to verify that the policy has been created.

When there are deployment errors:

  • Navigate to Management Groups in Azure Portal
  • Select the top level management group (i.e. pubsec)
  • Select Deployments
  • Review the deployment errors

New custom policy set definition & assignment

Steps

Step 1: Create policy set definition template

  1. Navigate to policy/custom/definitions/policyset and create two files. Replace POLICY_SET_DEFINITION with the name of your assignment such as loganalytics.

    • POLICY_SET_DEFINITION.bicep (i.e. loganalytics.bicep) - this file defines the policy set definition deployment
    • POLICY_SET_DEFINITION.parameters.json (i.e. loganalytics.parameters.json) - this file defines the parameters used to deploy the policy set definition

  2. Edit the Bicep file to include the following template. This template can be customized as required. Pre-requisites are:

    • targetScope must be managementGroup
    • parameter policyDefinitionManagementGroupId must be defined. This parameter identifies the scope of the policy set definition (i.e. pubsec).

    Example See Log Analytics Policy Set definition.

    Sample Template

      targetScope = 'managementGroup'

  @description('Management Group scope for the policy definition.')
  param policyDefinitionManagementGroupId string

  var customPolicyDefinitionMgScope = tenantResourceId('Microsoft.Management/managementGroups', policyDefinitionManagementGroupId)

  resource policyset_name 'Microsoft.Authorization/policySetDefinitions@2020-03-01' = {
    // Policy definition name.  This value is used when setting up the policy assignment template in the follow steps.  It should be all lowercase and no spaces.
    // i.e. name: 'custom-enable-logging-to-loganalytics'
    name: '<< NAME >>
    properties: {
      // Display name for the policy set definition
      displayName: '<< POLICY SET DEFINITION DISPLAY NAME >> '
      parameters: {
        // Add any parameters required for the policy set definition.  These parameters are used to pass down information to each policy.
      }
      policyDefinitionGroups: [
        // Define policy definition groups.  These are arbitrary groups that can be created based on your organization's requirements.
        // The group names are referenced when defining the policies.
        {
          name: 'BUILTIN'
          displayName: 'Additional Controls as Builtin Policies'
        }
        {
          name: 'CUSTOM'
          displayName: 'Additional Controls as Custom Policies'
        }
      ]
      policyDefinitions: [
        // List the policies in this policy set.  Repeat this block for every policy definition

        // An example of a built in policy where the policy definition id can be retrieved from Azure Portal.
        {
          groupNames: [
            'BUILTIN'
          ]
          policyDefinitionId: '/providers/Microsoft.Authorization/policyDefinitions/5ee9e9ed-0b42-41b7-8c9c-3cfb2fbe2069'
          policyDefinitionReferenceId: toLower(replace('Deploy Log Analytics agent for Linux virtual machine scale sets', ' ', '-'))
          parameters: {
            // Set the values of parameters for each policy.
          }
        }

        // An example of a custom policy where the policy definition id is inferred from the customPolicyDefinitionMgScope variable.
        // The policy definition name is the directory name.  In this example the directory is 'LA-Logs-Diagnostic-Settings' and located in /policy/custom/definitions/policy/LA-Logs-Diagnostic-Settings
        {
          groupNames: [
            'CUSTOM'
          ]
          policyDefinitionId: extensionResourceId(customPolicyDefinitionMgScope, 'Microsoft.Authorization/policyDefinitions', 'LA-Logs-Diagnostic-Settings')
          policyDefinitionReferenceId: toLower(replace('Audit diagnostic setting', ' ', '-'))
          parameters: {
            listOfResourceTypes: {
              value: '[parameters(\'listOfResourceTypesToAuditDiagnosticSettings\')]'
            }
          }
        }
      ]
    }
  }

  3. Edit the JSON parameters file to define the input parameters for the Bicep template. This JSON parameters file is used by Azure Resource Manager (ARM) for runtime inputs.

    You can use any of the templated parameters to set values based on environment configuration or hard code them as needed.

    Sample Template

      {
      "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
      "contentVersion": "1.0.0.0",
      "parameters": {
          "policyDefinitionManagementGroupId": {
              "value": "{{var-topLevelManagementGroupName}}"
          },
          "EXTRA_POLICY_SET_ASSIGNMENT_PARAMETER_NAME_1": {
              "value": "EXTRA_POLICY_SET_ASSIGNMENT_PARAMETER_VALUE_1"
          },
          "EXTRA_POLICY_SET_ASSIGNMENT_PARAMETER_NAME_2": {
              "value": "EXTRA_POLICY_SET_ASSIGNMENT_PARAMETER_VALUE_2"
          }
      }
  }

    Example: Log Analytics Policy Set Parameters

      {
      "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
      "contentVersion": "1.0.0.0",
      "parameters": {
          "policyDefinitionManagementGroupId": {
              "value": "{{var-topLevelManagementGroupName}}"
          }
      }
  }

Step 2: Create policy set assignment template

  1. Navigate to /policy/custom/assignments and create two files. Replace POLICY_SET_ASSIGNMENT with the name of your assignment such as loganalytics.

    • POLICY_SET_ASSIGNMENT.bicep (i.e. loganalytics.bicep) - this file defines the policy set assignment deployment
    • POLICY_SET_ASSIGNMENT.parameters.json (i.e. loganalytics.parameters.json) - this file defines the parameters used to deploy the policy set assignment

  2. Edit the Bicep file to include the following template. This template can be customized as required. Pre-requisites are:

    • targetScope must be managementGroup
    • parameter policyDefinitionManagementGroupId must be defined. This parameter identifies the scope of the policy set definition (i.e. pubsec).
    • parameter policyAssignmentManagementGroupId must be defined. This parameter identifies the scope of the policy set assignment (i.e. pubsec).

    Sample Template

    targetScope = 'managementGroup'

@description('Management Group scope for the policy definition.')
param policyDefinitionManagementGroupId string

@description('Management Group scope for the policy assignment.')
param policyAssignmentManagementGroupId string

@allowed([
  'Default'
  'DoNotEnforce'
])
@description('Policy set assignment enforcement mode.  Possible values are { Default, DoNotEnforce }.  Default value:  Default')
param enforcementMode string = 'Default'

// Start - Any custom parameters required for your policy set assignment
param ...
// End - Any custom parameters required for your policy set assignment

var policyId = '<< NAME OF THE POLICY SET DEFINITION >>'
var assignmentName = '<< DISPLAY NAME OF THE POLICY SET ASSIGNMENT >>'

var scope = tenantResourceId('Microsoft.Management/managementGroups', policyAssignmentManagementGroupId)
var policyScopedId = '/providers/Microsoft.Management/managementGroups/${policyDefinitionManagementGroupId}/providers/Microsoft.Authorization/policySetDefinitions/${policyId}'

resource policySetAssignment 'Microsoft.Authorization/policyAssignments@2020-03-01' = {
  // Set the name of the policy set assignment
  // Example: name: 'logging-${uniqueString('law-',policyAssignmentManagementGroupId)}'

  name: '<< NAME >>'

  properties: {
    displayName: assignmentName
    policyDefinitionId: policyScopedId
    scope: scope
    notScopes: [
    ]
    parameters: {
      // Add any parameters identified earlier into this section
    }
    // The policy assignment enforcement mode. Possible values are Default and DoNotEnforce.
    enforcementMode: enforcementMode
  }
  identity: {
    type: 'SystemAssigned'
  }
  location: deployment().location
}

// These role assignments are required to allow Policy Assignment to remediate.
// Add this section only when there are permissions to assign to the policy set.
// Ensure that the name is a GUID and generated with a deterministic formula such as the example below.
// Set the role definition id based on the policies in the policy set
resource policySetRoleAssignmentLogAnalyticsContributor 'Microsoft.Authorization/roleAssignments@2020-04-01-preview' = {
  name: guid(policyAssignmentManagementGroupId, 'loganalytics', 'Log Analytics Contributor')
  scope: managementGroup()
  properties: {
    roleDefinitionId: '/providers/Microsoft.Authorization/roleDefinitions/92aaf0da-9dab-42b6-94a3-d43ce8d16293'
    principalId: policySetAssignment.identity.principalId
    principalType: 'ServicePrincipal'
  }
}

    Example: Log Analytics Policy Set Assignment

      targetScope = 'managementGroup'

  @description('Management Group scope for the policy definition.')
  param policyDefinitionManagementGroupId string

  @description('Management Group scope for the policy assignment.')
  param policyAssignmentManagementGroupId string

  @allowed([
    'Default'
    'DoNotEnforce'
  ])
  @description('Policy set assignment enforcement mode.  Possible values are { Default, DoNotEnforce }.  Default value:  Default')
  param enforcementMode string = 'Default'

  @description('Log Analytics Workspace Resource Id')
  param logAnalyticsResourceId string

  @description('Log Analytics Workspace Id')
  param logAnalyticsWorkspaceId string

  var policyId = 'custom-enable-logging-to-loganalytics'
  var assignmentName = 'Custom - Log Analytics for Azure Services'

  var scope = tenantResourceId('Microsoft.Management/managementGroups', policyAssignmentManagementGroupId)
  var policyScopedId = '/providers/Microsoft.Management/managementGroups/${policyDefinitionManagementGroupId}/providers/Microsoft.Authorization/policySetDefinitions/${policyId}'

  resource policySetAssignment 'Microsoft.Authorization/policyAssignments@2020-03-01' = {
    name: 'logging-${uniqueString('law-',policyAssignmentManagementGroupId)}'
    properties: {
      displayName: assignmentName
      policyDefinitionId: policyScopedId
      scope: scope
      notScopes: [
      ]
      parameters: {
        logAnalytics: {
          value: logAnalyticsResourceId
        }
        logAnalyticsWorkspaceId: {
          value: logAnalyticsWorkspaceId
        }
      }
      enforcementMode: enforcementMode
    }
    identity: {
      type: 'SystemAssigned'
    }
    location: deployment().location
  }

  // These role assignments are required to allow Policy Assignment to remediate.
  resource policySetRoleAssignmentLogAnalyticsContributor 'Microsoft.Authorization/roleAssignments@2020-04-01-preview' = {
    name: guid(policyAssignmentManagementGroupId, 'loganalytics', 'Log Analytics Contributor')
    scope: managementGroup()
    properties: {
      roleDefinitionId: '/providers/Microsoft.Authorization/roleDefinitions/92aaf0da-9dab-42b6-94a3-d43ce8d16293'
      principalId: policySetAssignment.identity.principalId
      principalType: 'ServicePrincipal'
    }
  }

  resource policySetRoleAssignmentVirtualMachineContributor 'Microsoft.Authorization/roleAssignments@2020-04-01-preview' = {
    name: guid(policyAssignmentManagementGroupId, 'loganalytics', 'Virtual Machine Contributor')
    scope: managementGroup()
    properties: {
      roleDefinitionId: '/providers/Microsoft.Authorization/roleDefinitions/9980e02c-c2be-4d73-94e8-173b1dc7cf3c'
      principalId: policySetAssignment.identity.principalId
      principalType: 'ServicePrincipal'
    }
  }

  resource policySetRoleAssignmentMonitoringContributor 'Microsoft.Authorization/roleAssignments@2020-04-01-preview' = {
    name: guid(policyAssignmentManagementGroupId, 'loganalytics', 'Monitoring Contributor')
    scope: managementGroup()
    properties: {
      roleDefinitionId: '/providers/Microsoft.Authorization/roleDefinitions/749f88d5-cbae-40b8-bcfc-e573ddc772fa'
      principalId: policySetAssignment.identity.principalId
      principalType: 'ServicePrincipal'
    }
  }

  3. Edit the JSON parameters file to define the input parameters for the Bicep template. This JSON parameters file is used by Azure Resource Manager (ARM) for runtime inputs.

    You can use any of the templated parameters to set values based on environment configuration or hard code them as needed.

    Sample Template

      {
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
      "policyDefinitionManagementGroupId": {
          "value": "{{var-topLevelManagementGroupName}}"
      },
      "policyAssignmentManagementGroupId": {
          "value": "{{var-policyAssignmentManagementGroupId}}"
      },
      "enforcementMode": {
          "value": "Default"
      },
      "EXTRA_POLICY_ASSIGNMENT_PARAMETER_NAME_1": {
          "value": "EXTRA_POLICY_ASSIGNMENT_PARAMETER_VALUE_1"
      },
      "EXTRA_POLICY_ASSIGNMENT_PARAMETER_NAME_2": {
          "value": "EXTRA_POLICY_ASSIGNMENT_PARAMETER_VALUE_2"
      }
    }
  }

    Example: Log Analytics Policy Set Parameters

      {
      "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
      "contentVersion": "1.0.0.0",
      "parameters": {
        "policyDefinitionManagementGroupId": {
            "value": "{{var-topLevelManagementGroupName}}"
        },
        "policyAssignmentManagementGroupId": {
            "value": "{{var-policyAssignmentManagementGroupId}}"
        },
        "enforcementMode": {
            "value": "Default"
        },
        "logAnalyticsWorkspaceId": {
            "value": "{{var-logging-logAnalyticsWorkspaceId}}"
        },
        "logAnalyticsResourceId": {
            "value": "{{var-logging-logAnalyticsWorkspaceResourceId}}"
        }
      }
  }

Step 3: Configure Azure DevOps Pipeline

  • Edit /.pipelines/policy.yml
  • Navigate to the CustomPolicyJob Job definition
  • Navigate to the Define Policy Set Step definition and add the policy definition file name (without extension) to the deployTemplates array parameter
  • Navigate to the Assign Policy Set Step definition and add the policy assignment file name (without extension) to the deployTemplates array parameter

Step 4: Deploy definition & assignment

Execute Azure DevOps Policy pipeline to deploy. The policy set definition and assignment will be deployed to the top level management group (i.e. pubsec).

It takes around 30 minutes for the assignment to be applied to the defined scope. Once it's applied, the evaluation cycle begins for resources within that scope against the newly assigned policy or initiative and depending on the effects used by the policy or initiative, resources are marked as compliant, non-compliant, or exempt. A large policy or initiative evaluated against a large scope of resources can take time. As such, there's no pre-defined expectation of when the evaluation cycle completes. Once it completes, updated compliance results are available in the portal and SDKs. See Azure Docs for more information.

Step 5: Verify policy set definition and assignment deployment

Navigate to Azure Policy Definitions and Azure Policy Assignments to verify that the policy set has been created.

When there are deployment errors:

  • Navigate to Management Groups in Azure Portal
  • Select the top level management group (i.e. pubsec)
  • Select Deployments
  • Review the deployment errors

Update custom policy definition

Steps

Step 1: Update policy definition

Update azurepolicy.config.json, azurepolicy.parameters.json and azurepolicy.rules.json as required.

Step 2: Verify policy definition deployment after update

Execute Azure DevOps Policy pipeline to automatically deploy the policy definition update.

Navigate to Azure Policy Definitions to verify that the policy has been updated.

It takes around 30 minutes for the update to be applied. Once it's applied, the evaluation cycle begins for resources within that scope against the newly assigned policy or initiative and depending on the effects used by the policy or initiative, resources are marked as compliant, non-compliant, or exempt. A large policy or initiative evaluated against a large scope of resources can take time. As such, there's no pre-defined expectation of when the evaluation cycle completes. Once it completes, updated compliance results are available in the portal and SDKs. See Azure Docs for more information.

When there are deployment errors:

  • Navigate to Management Groups in Azure Portal
  • Select the top level management group (i.e. pubsec)
  • Select Deployments
  • Review the deployment errors

Update custom policy set definition & assignment

Steps

Step 1: Update policy set definition & assignment

  • Update policy set definition Bicep template & JSON parameters as required.
  • Update policy set assignment Bicep template & JSON parameters as required (typically when a new role assignment expected to support a new policy).

Consider when updating a policy set definition & assignment:

  • Any new parameter added to the policy set definition must have a default value to stay backward compatible with existing assignments.
  • Ensure that any new role assignments are incorporated in the policy assignment definition.
  • Avoid changing the policy set definition name. If this is required, remove the policy set assignment and its role assignments first.
  • Avoid changing the policy set role assignment names. If this is required, remove the policy set assignment and its role assignments first.

Step 2: Verify policy set definition & assignment after update

Execute Azure DevOps Policy pipeline to deploy the policy set definition & assignment update.

Navigate to Azure Policy Definitions and Azure Policy Assignments to verify that the policy set has been updated.

When there are deployment errors:

  • Navigate to Management Groups in Azure Portal
  • Select the top level management group (i.e. pubsec)
  • Select Deployments
  • Review the deployment errors

Remove custom policy definition

Azure DevOps Pipeline does not remove the custom policy definition from Azure. It will only remove the policy definition reference from the custom policy sets that are managed through automation. You must manually delete the policy definition using Azure Policy Definitions in Azure Portal.

Steps

Step 1: Remove policy definition

  • Navigate to /policy/custom/definitions/policy and identify the custom policy definition directory to delete.
  • Identify all custom policy set definitions that reference the policy (they are referenced using the directory name) and remove the references.
  • Delete the custom policy definition directory in policy/custom/definitions/policy
  • Execute Azure DevOps Policy pipeline to deploy the updates.

Remove custom policy set definition and assignment

Automation does not remove an existing policy set assignment. Removing the policy set assignment from the Azure DevOps pipeline ensures that it's no longer created. Any existing policy set assignments must be deleted manually.

Steps

Step 1: Remove custom policy set definition

  • Navigate to /policy/custom/definitions/policyset and delete the policy set definition Bicep template and JSON parameter files.

Step 2: Remove custom policy set assignment

  • Navigate to /policy/custom/assignments and delete the policy set assignment Bicep template and JSON parameter files.

Step 3: Remove custom policy set from Azure DevOps Pipeline

  • Edit /.pipelines/policy.yml
  • Navigate to the CustomPolicyJob Job definition
  • Navigate to the Define Policy Set Step definition and remove the policy definition file name from the deployTemplates array parameter
  • Navigate to the Assign Policy Set Step definition and remove the policy assignment file name from the deployTemplates array parameter

Step 4: Remove custom policy set assignment's IAM assignments

  • Navigate to Azure Policy Assignments in Azure Portal
    • Find the policy set assignment
    • Click on the ... beside the policy set assignment and select Delete assignment
  • Navigate to Management Groups in Azure Portal
    • Select the top level management group (i.e. pubsec)
    • Select Access control (IAM)
    • Select Role Assignments
    • Use the Type filter to find any Unknown role assignments and delete them. This step is required since deleting the policy set assignment does not automatically remove any role assignments. When the policy set assignment is removed, it's managed identity is also removed thus marking these role assignments as Unknown.

Enable or disable custom policy set enforcement

You may want to evaluate the compliance in your environment without any automatic remediation, either through DeployIfNotExists or modify policies. To support this scenario, all policy set assignments support an enforcementMode setting. This can be set to either: Default or DoNotEnforce:

  • Default = enable policy set enforcement
  • DoNotEnforce = disable policy set enforcement

Please review guidance and expected behaviour of these settings prior to making any modification:

You can switch between these modes per-policy set based on your Azure Policy adoption strategy.

To manage this setting:

  • Navigate to policy/custom/assignments
  • Open *.parameters.json. There is 1 parameters file per policy set assignment
  • Modify enforcementMode parameter with either Default or DoNotEnforce
  • Re-run the policy-ci Azure DevOps pipeline to update Azure

Auto generate custom Diagnostic Settings policies for PaaS services

Before auto generating a custom Diagnostic Settings policy, we recommend searching for a suitable built-in policy through Azure Policy Definitions.

The Diagnostic Settings policies in this reference implementation were created using scripts from GitHub (JimGBritt/AzurePolicy). The steps are:

  1. Deploy an instance of the Azure Service (i.e. Azure Bastion)
  2. Execute Create-AzDiagPolicy.PS1 - Follow instructions in GitHub
  3. Use the instructions for creating new custom policy definition to copy the generated content.
    • Copy the contents into azurepolicy.parameters.json and azurepolicy.rules.json.
    • Create azurepolicy.config.json with policy name and mode.
  4. Delete the instance created in Step 1.