Syntax Properties Return values Examples

AWS::CloudWatch::CompositeAlarm

The AWS::CloudWatch::CompositeAlarm type creates or updates a composite alarm. When you create a composite alarm, you specify a rule expression for the alarm that takes into account the alarm states of other alarms that you have created. The composite alarm goes into ALARM state only if all conditions of the rule are met.

The alarms specified in a composite alarm's rule expression can include metric alarms and other composite alarms.

Using composite alarms can reduce alarm noise. You can create multiple metric alarms, and also create a composite alarm and set up alerts only for the composite alarm. For example, you could create a composite alarm that goes into ALARM state only when more than one of the underlying metric alarms are in ALARM state.

When this operation creates an alarm, the alarm state is immediately set to INSUFFICIENT_DATA. The alarm is then evaluated and its state is set appropriately. Any actions associated with the new state are then executed. For a composite alarm, this initial time after creation is the only time that the alarm can be in INSUFFICIENT_DATA state.

When you update an existing alarm, its state is left unchanged, but the update completely overwrites the previous configuration of the alarm.

Syntax

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

JSON


{
  "Type" : "AWS::CloudWatch::CompositeAlarm",
  "Properties" : {
      "ActionsEnabled" : Boolean,
      "ActionsSuppressor" : String,
      "ActionsSuppressorExtensionPeriod" : Integer,
      "ActionsSuppressorWaitPeriod" : Integer,
      "AlarmActions" : [ String, ... ],
      "AlarmDescription" : String,
      "AlarmName" : String,
      "AlarmRule" : String,
      "InsufficientDataActions" : [ String, ... ],
      "OKActions" : [ String, ... ],
      "Tags" : [ Tag, ... ]
    }
}

YAML


Type: AWS::CloudWatch::CompositeAlarm
Properties:
  ActionsEnabled: Boolean
  ActionsSuppressor: String
  ActionsSuppressorExtensionPeriod: Integer
  ActionsSuppressorWaitPeriod: Integer
  AlarmActions: 
    - String
  AlarmDescription: String
  AlarmName: String
  AlarmRule: String
  InsufficientDataActions: 
    - String
  OKActions: 
    - String
  Tags: 
    - Tag

Properties

ActionsEnabled

Indicates whether actions should be executed during any changes to the alarm state of the composite alarm. The default is TRUE.

Required: No

Type: Boolean

Update requires: No interruption

ActionsSuppressor

Actions will be suppressed if the suppressor alarm is in the ALARM state. ActionsSuppressor can be an AlarmName or an Amazon Resource Name (ARN) from an existing alarm.

Required: No

Type: String

Minimum: 1

Maximum: 1600

Update requires: No interruption

ActionsSuppressorExtensionPeriod

The maximum time in seconds that the composite alarm waits after suppressor alarm goes out of the ALARM state. After this time, the composite alarm performs its actions.

Important

ExtensionPeriod is required only when ActionsSuppressor is specified.

Required: No

Type: Integer

Minimum: 0

Update requires: No interruption

ActionsSuppressorWaitPeriod

The maximum time in seconds that the composite alarm waits for the suppressor alarm to go into the ALARM state. After this time, the composite alarm performs its actions.

Important

WaitPeriod is required only when ActionsSuppressor is specified.

Required: No

Type: Integer

Minimum: 0

Update requires: No interruption

AlarmActions

The actions to execute when this alarm transitions to the ALARM state from any other state. Each action is specified as an Amazon Resource Name (ARN). For more information about creating alarms and the actions that you can specify, see PutCompositeAlarm in the Amazon CloudWatch API Reference.

Required: No

Type: Array of String

Minimum: 1

Maximum: 1024 | 5

Update requires: No interruption

AlarmDescription

The description for the composite alarm.

Required: No

Type: String

Minimum: 0

Maximum: 1024

Update requires: No interruption

AlarmName

The name for the composite alarm. This name must be unique within your AWS account.

Required: No

Type: String

Minimum: 1

Maximum: 255

Update requires: Replacement

AlarmRule

An expression that specifies which other alarms are to be evaluated to determine this composite alarm's state. For each alarm that you reference, you designate a function that specifies whether that alarm needs to be in ALARM state, OK state, or INSUFFICIENT_DATA state. You can use operators (AND, OR and NOT) to combine multiple functions in a single expression. You can use parenthesis to logically group the functions in your expression.

You can use either alarm names or ARNs to reference the other alarms that are to be evaluated.

Functions can include the following:

ALARM("alarm-name or alarm-ARN") is TRUE if the named alarm is in ALARM state.
OK("alarm-name or alarm-ARN") is TRUE if the named alarm is in OK state.
INSUFFICIENT_DATA("alarm-name or alarm-ARN") is TRUE if the named alarm is in INSUFFICIENT_DATA state.
TRUE always evaluates to TRUE.
FALSE always evaluates to FALSE.

TRUE and FALSE are useful for testing a complex AlarmRule structure, and for testing your alarm actions.

For more information about AlarmRule syntax, see PutCompositeAlarm in the Amazon CloudWatch API Reference.

Required: Yes

Type: String

Minimum: 1

Maximum: 10240

Update requires: No interruption

InsufficientDataActions

The actions to execute when this alarm transitions to the INSUFFICIENT_DATA state from any other state. Each action is specified as an Amazon Resource Name (ARN). For more information about creating alarms and the actions that you can specify, see PutCompositeAlarm in the Amazon CloudWatch API Reference.

Required: No

Type: Array of String

Minimum: 1

Maximum: 1024 | 5

Update requires: No interruption

OKActions

The actions to execute when this alarm transitions to the OK state from any other state. Each action is specified as an Amazon Resource Name (ARN). For more information about creating alarms and the actions that you can specify, see PutCompositeAlarm in the Amazon CloudWatch API Reference.

Required: No

Type: Array of String

Minimum: 1

Maximum: 1024 | 5

Update requires: No interruption

Tags

A list of key-value pairs to associate with the alarm. You can associate as many as 50 tags with an alarm. To be able to associate tags with the alarm when you create the alarm, you must have the cloudwatch:TagResource permission.

Tags can help you organize and categorize your resources. You can also use them to scope user permissions by granting a user permission to access or change only resources with certain tag values.

Required: No

Type: Array of Tag

Maximum: 50

Update requires: No interruption

Return values

Ref

When you pass the logical ID of this resource to the intrinsic Ref function, Ref returns the alarm name, such as MyCompositeAlarm.

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 ARN of the composite alarm, such as arn:aws:cloudwatch:us-west-2:123456789012:alarm/CompositeAlarmName.

Examples

Composite alarm based on two metric alarms and another composite alarm

This example creates composite alarms named "HighResourceUsage" and "DeploymentInProgress", and also creates metrics alarms named "HighCPUUsage" and "HighMemoryUsage". "DeploymentInProgress" is an alarm that must be manually set to TRUE or FALSE. The "HighResourceUsage" alarm goes into ALARM state only if both "HighCPUUsage" and "HighMemoryUsage" are in ALARM state, and if "DeploymentInProgress" is FALSE. Only "HighResourceUsage" has the alarm action of notifying SNS. This reduces alarm noise, so that you are alerted only if both CPU usage and memory usage are high, and a deployment is not currently in progress.

JSON


"Resources": {
    "HighResourceUsage": {
        "Type": "AWS::CloudWatch::CompositeAlarm",
        "Properties": {
            "AlarmName": "HighResourceUsage",
            "AlarmRule": "(ALARM(HighCPUUsage) OR ALARM(HighMemoryUsage)) AND NOT ALARM(DeploymentInProgress)",
            "AlarmActions": [ {"arn:aws:sns:us-west-2:123456789012:my-sns-topic"} },
            "AlarmDescription": "Indicates that the system resource usage is high while no known 
            deployment is in progress"
        },
        "DependsOn": [
            "DeploymentInProgress",
            "HighCPUUsage",
            "HighMemoryUsage"
        ]
    },
    "DeploymentInProgress": {
        "Type": "AWS::CloudWatch::CompositeAlarm",
        "Properties": {
            "AlarmName": "DeploymentInProgress",
            "AlarmRule": "FALSE",
            "AlarmDescription": "Manually updated to TRUE/FALSE to disable other alarms"
        }
    },
    "HighCPUUsage": {
        "Type": "AWS::CloudWatch::Alarm",
        "Properties": {
            "AlarmDescription": "CPUusageishigh",
            "AlarmName": "HighCPUUsage",
            "ComparisonOperator": "GreaterThanThreshold",
            "EvaluationPeriods": 1,
            "MetricName": "CPUUsage",
            "Namespace": "CustomNamespace",
            "Period": 60,
            "Statistic": "Average",
            "Threshold": 70,
            "TreatMissingData": "notBreaching"
        }
    },
    "HighMemoryUsage": {
        "Type": "AWS::CloudWatch::Alarm",
        "Properties": {
            "AlarmDescription": "Memoryusageishigh",
            "AlarmName": "HighMemoryUsage",
            "ComparisonOperator": "GreaterThanThreshold",
            "EvaluationPeriods": 1,
            "MetricName": "MemoryUsage",
            "Namespace": "CustomNamespace",
            "Period": 60,
            "Statistic": "Average",
            "Threshold": 65,
            "TreatMissingData": "breaching"
        }
    }
}

YAML


Resources:
  HighResourceUsage:
    Type: AWS::CloudWatch::CompositeAlarm
    Properties:
      AlarmName: HighResourceUsage
      AlarmRule: !Sub "(ALARM(${HighCPUUsage}) OR ALARM(${HighMemoryUsage})) AND NOT ALARM(${DeploymentInProgress})"
      AlarmActions: [
         arn:aws:sns:us-west-2:123456789012:my-sns-topic
      ]
      AlarmDescription: Indicates that the system resource usage is high while no known deployment is in progress
    DependsOn:
    - DeploymentInProgress
    - HighCPUUsage
    - HighMemoryUsage
  DeploymentInProgress:
    Type: AWS::CloudWatch::CompositeAlarm
    Properties:
      AlarmName: DeploymentInProgress
      AlarmRule: 
      AlarmDescription: Manually updated to TRUE/FALSE to disable other alarms
  HighCPUUsage: 
    Type: AWS::CloudWatch::Alarm
    Properties: 
      AlarmDescription: CPU usage is high
      AlarmName: HighCPUUsage
      ComparisonOperator: GreaterThanThreshold
      EvaluationPeriods: 1
      MetricName: CPUUsage
      Namespace: CustomNamespace
      Period: 60
      Statistic: Average
      Threshold: 70
      TreatMissingData: notBreaching
  HighMemoryUsage: 
    Type: AWS::CloudWatch::Alarm
    Properties: 
      AlarmDescription: Memory usage is high
      AlarmName: HighMemoryUsage
      ComparisonOperator: GreaterThanThreshold
      EvaluationPeriods: 1
      MetricName: MemoryUsage
      Namespace: CustomNamespace
      Period: 60
      Statistic: Average
      Threshold: 65
      TreatMissingData: breaching

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