【Azure Policy】使用deployIfNotExists 把 Azure Activity logs 导出保存在Storage Account

问题描述

使用Azure Policy，对订阅下的全部Activity Log配置Diagnostic Setting，要求：

1. 在Subscription或Management Group级别，针对未启用Activity Log功能的订阅，启用Activity Log功能；
2. 对已经启用了Activity log功能的订阅，使用该Policy纠正并统一其参数配置；
3. 所收集到的Azure Activity Log存储在特定的Storage Account，保留周期为6个月；
4. Activity logs将收集一下log:

• • Administrative 
  • Security 
  • Alert 
  • Recommendation 
  • ResourceHealth

 

 

 

问题解答

针对需求，一条一条的匹配

 

1. 在Subscription或Management Group级别，针对未启用Activity Log功能的订阅，启用Activity Log功能

因为需要Policy Scan的资源为 Subscription，所以第一步是需要扫描所有的订阅资源。然后在检查订阅下的Microsoft.Insights/diagnosticSettings配置。

    "policyRule": {
      "if": {
        "field": "type",
        "equals": "Microsoft.Resources/subscriptions"
      },

2. 对已经启用了Activity log功能的订阅，使用该Policy纠正并统一其参数配置

3. 所收集到的Azure Activity Log存储在特定的Storage Account，保留周期为6个月

第三点中：需要特定的Storage Account，所以把它作为Policy参数进行设置，然后判断storageAccountId 值是否一样。6个月的保留周期设置因为新的UI上没有这个设定值，所以需要创建Storage Account中去设置，不在Policy中实现。

第二点中：要求使用同一个Storage Acocunt，所以这里并不是判断是否配置了Storage Account，而是必须要使用ID相等。

    {
                "field": "Microsoft.Insights/diagnosticSettings/storageAccountId",
                "equals": "[parameters('storageAccount')]"
   },

4. Activity logs将收集一下log: a). Administrative b). Security c). Alert d). Recommendation e). ResourceHealth

因为DiagnosticSettings 在ARM资源中是数组对象，所以使用logs[*] ， 并且通过count  where equals 运算符。

当Policy的条件满足后，接下来就是需要考虑DeployIfNotExists的配置了

• ExistenceScope ： 允许的值为 Subscription 和 ResourceGroup， 但是默认值为Resource Group。所以此处必须修改为Subscription
• ExistenceCondition ：如果任何匹配的相关资源评估结果为 true，该效果就会得到满足并且不会触发部署。
• DeploymentScope：允许的值为 Subscription 和 ResourceGroup， 默认值是 ResourceGroup。因为修改的资源为订阅的诊断配置。所以需要设置该值，并且也必须在Deployment中指定location属性。否则会遇见the location is missing 报错。

 

完整的Policy

{
    "mode": "All",
    "policyRule": {
        "if": {
            "field": "type",
            "equals": "Microsoft.Resources/subscriptions"
        },
        "then": {
            "effect": "[parameters('effect')]",
            "details": {
                "type": "Microsoft.Insights/diagnosticSettings",
                "ExistenceScope": "Subscription",
                "existenceCondition": {
                    "allOf": [
                        {
                            "field": "Microsoft.Insights/diagnosticSettings/storageAccountId",
                            "equals": "[parameters('storageAccount')]"
                        },
                        {
                            "count": {
                                "field": "Microsoft.Insights/diagnosticSettings/logs[*]",
                                "where": {
                                    "allOf": [
                                        {
                                            "anyof": [
                                                {
                                                    "field": "Microsoft.Insights/diagnosticSettings/logs[*].category",
                                                    "equals": "Administrative"
                                                },
                                                {
                                                    "field": "Microsoft.Insights/diagnosticSettings/logs[*].category",
                                                    "equals": "Security"
                                                },
                                                {
                                                    "field": "Microsoft.Insights/diagnosticSettings/logs[*].category",
                                                    "equals": "Alert"
                                                },
                                                {
                                                    "field": "Microsoft.Insights/diagnosticSettings/logs[*].category",
                                                    "equals": "Recommendation"
                                                },
                                                {
                                                    "field": "Microsoft.Insights/diagnosticSettings/logs[*].category",
                                                    "equals": "ResourceHealth"
                                                }
                                            ]
                                        },
                                        {
                                            "field": "Microsoft.Insights/diagnosticSettings/logs[*].enabled",
                                            "equals": "true"
                                        }
                                    ]
                                }
                            },
                            "equals": 5
                        }
                    ]
                },
                "deploymentScope": "subscription",
                "deployment": {
                    "location": "chinaeast2",
                    "properties": {
                        "mode": "incremental",
                        "template": {
                            "$schema": "https://schema.management.azure.com/schemas/2018-05-01/subscriptionDeploymentTemplate.json#",
                            "contentVersion": "1.0.0.0",
                            "parameters": {
                                "storageAccount": {
                                    "type": "string"
                                },
                                "logsEnabled": {
                                    "type": "string"
                                },
                                "profileName": {
                                    "type": "string"
                                }
                            },
                            "variables": {},
                            "resources": [
                                {
                                    "type": "Microsoft.Insights/diagnosticSettings",
                                    "apiVersion": "2017-05-01-preview",
                                    "name": "[parameters('profileName')]",
                                    "location": "global",
                                    "dependsOn": [],
                                    "properties": {
                                        "storageAccountId": "[parameters('storageAccount')]",
                                        "logs": [
                                            {
                                                "category": "Administrative",
                                                "enabled": "[parameters('logsEnabled')]"
                                            },
                                            {
                                                "category": "Security",
                                                "enabled": "[parameters('logsEnabled')]"
                                            },
                                            {
                                                "category": "Alert",
                                                "enabled": "[parameters('logsEnabled')]"
                                            },
                                            {
                                                "category": "Recommendation",
                                                "enabled": "[parameters('logsEnabled')]"
                                            },
                                            {
                                                "category": "ResourceHealth",
                                                "enabled": "[parameters('logsEnabled')]"
                                            }
                                        ]
                                    }
                                }
                            ],
                            "outputs": {}
                        },
                        "parameters": {
                            "storageAccount": {
                                "value": "[parameters('storageAccount')]"
                            },
                            "logsEnabled": {
                                "value": "[parameters('logsEnabled')]"
                            },
                            "profileName": {
                                "value": "[parameters('profileName')]"
                            }
                        }
                    }
                },
                "roleDefinitionIds": [
                    "/providers/Microsoft.Authorization/roleDefinitions/b24988ac-6180-42a0-ab88-20f7382dd24c",
                    "/providers/Microsoft.Authorization/roleDefinitions/17d1049b-9a84-46fb-8f53-869881c3d3ab"
                ]
            }
        }
    },
    "parameters": {
        "effect": {
            "type": "String",
            "metadata": {
                "displayName": "Effect",
                "description": "Enable or disable the execution of the policy"
            },
            "allowedValues": [
                "DeployIfNotExists",
                "Disabled"
            ],
            "defaultValue": "DeployIfNotExists"
        },
        "profileName": {
            "type": "String",
            "metadata": {
                "displayName": "Profile name",
                "description": "The diagnostic settings profile name"
            },
            "defaultValue": "setbypolicy_storageaccount"
        },
        "storageAccount": {
            "type": "String",
            "metadata": {
                "displayName": "Storage Account Name",
                "description": "Select storage account from dropdown list. If this workspace is outside of the scope of the assignment you must manually grant 'Log Analytics Contributor' permissions (or similar) to the policy assignment's principal ID.",
                "strongType": "Microsoft.Storage/storageAccounts",
                "assignPermissions": true
            },
            "defaultValue": "/subscriptions/<subscription id>/resourcegroups/<resource group name>/providers/microsoft.storage/storageaccounts/<storage account name>"
        },
        "logsEnabled": {
            "type": "String",
            "metadata": {
                "displayName": "Enable logs",
                "description": "Whether to enable logs stream to the Log Analytics workspace - True or False"
            },
            "allowedValues": [
                "True",
                "False"
            ],
            "defaultValue": "True"
        }
    }
}

 

可能遇见的错误

 1： location 错误

          "deploymentScope": "subscription",

          "deployment": {

            "location": "chinaeast2",

            "properties": {

Code

LocationNotAvailableForDeployment

Message

The provided location 'global' is not available for deployment. List of available regions is 'chinaeast2,chinaeast,chinanorth3,chinanorth,chinanorth2'.

Note:  If the location is missing or the value is incorrect, you will encounter the LocationNotAvailableForDeployment error, the Error Message will be "The provided location 'global' is not available for deployment. List of available regions is 'chinaeast2, chinaeast, chinanorth3, chinanorth, chinanorth2'."

2：设置： logs[*].enabled条件错误

{
    "field": "Microsoft.Insights/diagnosticSettings/logs[*].enabled",
    "equals": "true"
}

结果：

 

3： 设置：logs[*].category 条件错误

{
    "field": "Microsoft.Insights/diagnosticSettings/logs[*].category",
    "equals": "Administrative"
}

结果：

 

 参考资料

1. Azure Policy 模式：count 运算符 : https://docs.azure.cn/zh-cn/governance/policy/samples/pattern-count-operator
2. 了解 [*] 别名 : https://docs.azure.cn/zh-cn/governance/policy/concepts/definition-structure#understanding-the--alias
3. DeployIfNotExists 评估 ：https://docs.azure.cn/zh-cn/governance/policy/concepts/effects#deployifnotexists-evaluation