Syntax Properties Return values Examples

AWS::Config::ConfigRule

Specifies an AWS Config rule for evaluating whether your AWS resources comply with your desired configurations.

You can use this action for custom AWS Config rules and AWS managed Config rules. A custom AWS Config rule is a rule that you develop and maintain. An AWS managed Config rule is a customizable, predefined rule that AWS Config provides.

If you are adding a new custom AWS Config rule, you must first create the AWS Lambda function that the rule invokes to evaluate your resources. When you use the PutConfigRule action to add the rule to AWS Config, you must specify the Amazon Resource Name (ARN) that AWS Lambda assigns to the function. Specify the ARN for the SourceIdentifier key. This key is part of the Source object, which is part of the ConfigRule object.

If you are adding an AWS managed Config rule, specify the rule's identifier for the SourceIdentifier key. To reference AWS managed Config rule identifiers, see About AWS Managed Config Rules.

For any new rule that you add, specify the ConfigRuleName in the ConfigRule object. Do not specify the ConfigRuleArn or the ConfigRuleId. These values are generated by AWS Config for new rules.

If you are updating a rule that you added previously, you can specify the rule by ConfigRuleName, ConfigRuleId, or ConfigRuleArn in the ConfigRule data type that you use in this request.

The maximum number of rules that AWS Config supports is 150.

For information about requesting a rule limit increase, see AWS Config Limits in the AWS General Reference Guide.

For more information about developing and using AWS Config rules, see Evaluating AWS Resource Configurations with AWS Config in the AWS Config Developer Guide.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON


{
  "Type" : "AWS::Config::ConfigRule",
  "Properties" : {
      "ConfigRuleName" : String,
      "Description" : String,
      "InputParameters" : Json,
      "MaximumExecutionFrequency" : String,
      "Scope" : Scope,
      "Source" : Source
    }
}

YAML


Type: AWS::Config::ConfigRule
Properties: 
  ConfigRuleName: String
  Description: String
  InputParameters: Json
  MaximumExecutionFrequency: String
  Scope: 
    Scope
  Source: 
    Source

Properties

ConfigRuleName

A name for the AWS Config rule. If you don't specify a name, AWS CloudFormation generates a unique physical ID and uses that ID for the rule name. For more information, see Name Type.

Required: No

Type: String

Minimum: 1

Maximum: 128

Pattern: .*\S.*

Update requires: Replacement

Description

The description that you provide for the AWS Config rule.

Required: No

Type: String

Minimum: 0

Maximum: 256

Update requires: No interruption

InputParameters

A string, in JSON format, that is passed to the AWS Config rule Lambda function.

Required: No

Type: Json

Minimum: 1

Maximum: 1024

Update requires: No interruption

MaximumExecutionFrequency

The maximum frequency with which AWS Config runs evaluations for a rule. You can specify a value for MaximumExecutionFrequency when:

You are using an AWS managed rule that is triggered at a periodic frequency.
Your custom rule is triggered when AWS Config delivers the configuration snapshot. For more information, see ConfigSnapshotDeliveryProperties.

Note

By default, rules with a periodic trigger are evaluated every 24 hours. To change the frequency, specify a valid value for the MaximumExecutionFrequency parameter.

Required: No

Type: String

Allowed values: One_Hour | Six_Hours | Three_Hours | Twelve_Hours | TwentyFour_Hours

Update requires: No interruption

Scope

Defines which resources can trigger an evaluation for the rule. The scope can include one or more resource types, a combination of one resource type and one resource ID, or a combination of a tag key and value. Specify a scope to constrain the resources that can trigger an evaluation for the rule. If you do not specify a scope, evaluations are triggered when any resource in the recording group changes.

Note

The scope can be empty.

Required: No

Type: Scope

Update requires: No interruption

Source

Provides the rule owner (AWS or customer), the rule identifier, and the notifications that cause the function to evaluate your AWS resources.

Required: Yes

Type: Source

Update requires: No interruption

Return values

Ref

When you pass the logical ID of this resource to the intrinsic Ref function, Ref returns the rule name, such as mystack-MyConfigRule-12ABCFPXHV4OV.

For more information about using the Ref function, see Ref.

Fn::GetAtt

The Fn::GetAtt intrinsic function returns a value for a specified attribute of this type. The following are the available attributes and sample return values.

For more information about using the Fn::GetAtt intrinsic function, see Fn::GetAtt.

Arn: The Amazon Resource Name (ARN) of the AWS Config rule, such as arn:aws:config:us-east-1:123456789012:config-rule/config-rule-a1bzhi.
Compliance.Type: The compliance status of an AWS Config rule, such as COMPLIANT or NON_COMPLIANT.
ConfigRuleId: The ID of the AWS Config rule, such as config-rule-a1bzhi.

Examples

Config Rule

The following example uses an AWS managed rule that checks whether EC2 volumes resource types have a CostCenter tag.

JSON


"ConfigRuleForVolumeTags": {
  "Type": "AWS::Config::ConfigRule",
  "Properties": {
    "InputParameters": {"tag1Key": "CostCenter"},
    "Scope": {
      "ComplianceResourceTypes": ["AWS::EC2::Volume"]
    },
    "Source": {
      "Owner": "AWS",
      "SourceIdentifier": "REQUIRED_TAGS"
    }
  }
}

YAML


ConfigRuleForVolumeTags: 
  Type: AWS::Config::ConfigRule
  Properties: 
    InputParameters: 
      tag1Key: CostCenter
    Scope: 
      ComplianceResourceTypes: 
        - "AWS::EC2::Volume"
    Source: 
      Owner: AWS
      SourceIdentifier: "REQUIRED_TAGS"

Rule Using Lambda Function

The following example creates a custom configuration rule that uses a Lambda function. The function checks whether an EC2 volume has the AutoEnableIO property set to true. Note that the configuration rule has a dependency on the Lambda policy so that the rule calls the function only after it's permitted to do so.

JSON


"ConfigPermissionToCallLambda": {
  "Type": "AWS::Lambda::Permission",
  "Properties": {
    "FunctionName": {"Fn::GetAtt": ["VolumeAutoEnableIOComplianceCheck", "Arn"]},
    "Action": "lambda:InvokeFunction",
    "Principal": "config.amazonaws.com"
  }
},
"VolumeAutoEnableIOComplianceCheck": {
  "Type": "AWS::Lambda::Function",
  "Properties": {
    "Code": {
      "ZipFile":  {"Fn::Join": ["\n", [
        "var aws  = require('aws-sdk');",
        "var config = new aws.ConfigService();",
        "var ec2 = new aws.EC2();",

        "exports.handler = function(event, context) {",
        "    compliance = evaluateCompliance(event, function(compliance, event) {",
        "        var configurationItem = JSON.parse(event.invokingEvent).configurationItem;",

        "        var putEvaluationsRequest = {",
        "            Evaluations: [{",
        "                ComplianceResourceType: configurationItem.resourceType,",
        "                ComplianceResourceId: configurationItem.resourceId,",
        "                ComplianceType: compliance,",
        "                OrderingTimestamp: configurationItem.configurationItemCaptureTime",
        "            }],",
        "            ResultToken: event.resultToken",
        "        };",

        "        config.putEvaluations(putEvaluationsRequest, function(err, data) {",
        "            if (err) context.fail(err);",
        "            else context.succeed(data);",
        "        });",
        "    });",
        "};",

        "function evaluateCompliance(event, doReturn) {",
        "    var configurationItem = JSON.parse(event.invokingEvent).configurationItem;",
        "    var status = configurationItem.configurationItemStatus;",
        "    if (configurationItem.resourceType !== 'AWS::EC2::Volume' || event.eventLeftScope || (status !== 'OK' && status !== 'ResourceDiscovered'))",
        "        doReturn('NOT_APPLICABLE', event);",
        "    else ec2.describeVolumeAttribute({VolumeId: configurationItem.resourceId, Attribute: 'autoEnableIO'}, function(err, data) {",
        "        if (err) context.fail(err);",
        "        else if (data.AutoEnableIO.Value) doReturn('COMPLIANT', event);",
        "        else doReturn('NON_COMPLIANT', event);",
        "    });",
        "}"
      ]]}
    },
    "Handler": "index.handler",
    "Runtime": "nodejs12.x",
    "Timeout": "30",
    "Role": {"Fn::GetAtt": ["LambdaExecutionRole", "Arn"]}
  }
},
"ConfigRuleForVolumeAutoEnableIO": {
  "Type": "AWS::Config::ConfigRule",
  "Properties": {
    "ConfigRuleName": "ConfigRuleForVolumeAutoEnableIO",
    "Scope": {
      "ComplianceResourceId": {"Ref": "Ec2Volume"},
      "ComplianceResourceTypes": ["AWS::EC2::Volume"]
    },
    "Source": {
      "Owner": "CUSTOM_LAMBDA",
      "SourceDetails": [{
          "EventSource": "aws.config",
          "MessageType": "ConfigurationItemChangeNotification"
      }],
      "SourceIdentifier": {"Fn::GetAtt": ["VolumeAutoEnableIOComplianceCheck", "Arn"]}
    }
  },
  "DependsOn": "ConfigPermissionToCallLambda"
}

YAML


ConfigPermissionToCallLambda: 
  Type: AWS::Lambda::Permission
  Properties: 
    FunctionName: 
      Fn::GetAtt: 
        - VolumeAutoEnableIOComplianceCheck
        - Arn
    Action: "lambda:InvokeFunction"
    Principal: "config.amazonaws.com"
VolumeAutoEnableIOComplianceCheck: 
  Type: AWS::Lambda::Function
  Properties: 
    Code: 
      ZipFile: 
        !Sub |
          var aws  = require('aws-sdk');
          var config = new aws.ConfigService();
          var ec2 = new aws.EC2();
          exports.handler = function(event, context) {
              compliance = evaluateCompliance(event, function(compliance, event) {
                    var configurationItem = JSON.parse(event.invokingEvent).configurationItem;
                    var putEvaluationsRequest = {
                        Evaluations: [{
                            ComplianceResourceType: configurationItem.resourceType,
                            ComplianceResourceId: configurationItem.resourceId,
                            ComplianceType: compliance,
                            OrderingTimestamp: configurationItem.configurationItemCaptureTime
                        }],
                        ResultToken: event.resultToken
                    };
                    config.putEvaluations(putEvaluationsRequest, function(err, data) {
                        if (err) context.fail(err);
                        else context.succeed(data);
                    });
                });
            };
            function evaluateCompliance(event, doReturn) {
                var configurationItem = JSON.parse(event.invokingEvent).configurationItem;
                var status = configurationItem.configurationItemStatus;
                if (configurationItem.resourceType !== 'AWS::EC2::Volume' || event.eventLeftScope || (status !== 'OK' && status !== 'ResourceDiscovered'))
                    doReturn('NOT_APPLICABLE', event);
                else ec2.describeVolumeAttribute({VolumeId: configurationItem.resourceId, Attribute: 'autoEnableIO'}, function(err, data) {
                    if (err) context.fail(err);
                    else if (data.AutoEnableIO.Value) doReturn('COMPLIANT', event);
                    else doReturn('NON_COMPLIANT', event);
                });
            }
    Handler: "index.handler"
    Runtime: nodejs12.x
    Timeout: 30
    Role: 
      Fn::GetAtt: 
        - LambdaExecutionRole
        - Arn
ConfigRuleForVolumeAutoEnableIO: 
  Type: AWS::Config::ConfigRule
  Properties: 
    ConfigRuleName: ConfigRuleForVolumeAutoEnableIO
    Scope: 
      ComplianceResourceId: 
        Ref: Ec2Volume
      ComplianceResourceTypes: 
        - "AWS::EC2::Volume"
    Source: 
      Owner: "CUSTOM_LAMBDA"
      SourceDetails: 
        - 
          EventSource: "aws.config"
          MessageType: "ConfigurationItemChangeNotification"
      SourceIdentifier: 
        Fn::GetAtt: 
          - VolumeAutoEnableIOComplianceCheck
          - Arn
  DependsOn: ConfigPermissionToCallLambda

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Document Conventions

AWS::Config::AggregationAuthorization

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