Boot Diagnostics - DeployIfNotExist

Enable_Boot_Diagnostics.json

{
  "mode": "All",
  "policyRule": {
    "if": {
      "allOf": [
        {
          "field": "type",
          "equals": "Microsoft.Compute/virtualMachines"
        },
        {
          "field": "tags",
          "notContains": "IgnoreBootDiagnostics"
        },
        {
          "field": "Microsoft.Compute/virtualMachines/diagnosticsProfile.bootDiagnostics.storageUri",
          "notContains": "[parameters('StorageURI')]"
        },
        {
          "not": {
            "field": "Microsoft.Compute/virtualMachines/diagnosticsProfile.bootDiagnostics.storageUri",
            "equals": ""
          }
        }
      ]
    },
    "then": {
      "effect": "modify",
      "details": {
        "roleDefinitionIds": [
          "/providers/Microsoft.Authorization/roleDefinitions/9980e02c-c2be-4d73-94e8-173b1dc7cf3c"
        ],
        "conflictEffect": "audit",
        "operations": [
          {
            "operation": "addOrReplace",
            "field": "Microsoft.Compute/virtualMachines/diagnosticsProfile.bootDiagnostics.storageUri",
            "value": "[parameters('StorageURI')]"
          },
          {
            "operation": "addOrReplace",
            "field": "Microsoft.Compute/virtualMachines/diagnosticsProfile.bootDiagnostics.enabled",
            "value": true
          }
        ]
      }
    }
  },
  "parameters": {
    "StorageURI": {
      "type": "String",
      "metadata": {
        "displayName": "StorageURI",
        "description": "Storage Account that will be applied to any account that does not already have one applied."
      },
      "defaultValue": "https://YourBlobStorage.blob.core.windows.net"
    }
  }
}