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Amazon CloudWatch
API Reference (API Version 2010-08-01)

PutMetricAlarm

Creates or updates an alarm and associates it with the specified metric. Optionally, this operation can associate one or more Amazon SNS resources with the alarm.

When this operation creates an alarm, the alarm state is immediately set to INSUFFICIENT_DATA. The alarm is evaluated and its state is set appropriately. Any actions associated with the state are then executed.

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

If you are an AWS Identity and Access Management (IAM) user, you must have Amazon EC2 permissions for some operations:

  • ec2:DescribeInstanceStatus and ec2:DescribeInstances for all alarms on EC2 instance status metrics

  • ec2:StopInstances for alarms with stop actions

  • ec2:TerminateInstances for alarms with terminate actions

  • ec2:DescribeInstanceRecoveryAttribute and ec2:RecoverInstances for alarms with recover actions

If you have read/write permissions for Amazon CloudWatch but not for Amazon EC2, you can still create an alarm, but the stop or terminate actions won't be performed. However, if you are later granted the required permissions, the alarm actions that you created earlier will be performed.

If you are using an IAM role (for example, an Amazon EC2 instance profile), you cannot stop or terminate the instance using alarm actions. However, you can still see the alarm state and perform any other actions such as Amazon SNS notifications or Auto Scaling policies.

If you are using temporary security credentials granted using the AWS Security Token Service (AWS STS), you cannot stop or terminate an Amazon EC2 instance using alarm actions.

Note that you must create at least one stop, terminate, or reboot alarm using the Amazon EC2 or CloudWatch console to create the EC2ActionsAccess IAM role. After this IAM role is created, you can create stop, terminate, or reboot alarms using a command-line interface or an API.

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

ActionsEnabled

Indicates whether actions should be executed during any changes to the alarm state.

Type: Boolean

Required: No

AlarmActions.member.N

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).

Valid Values: arn:aws:automate:region:ec2:stop | arn:aws:automate:region:ec2:terminate | arn:aws:automate:region:ec2:recover

Valid Values (for use with IAM roles): arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Stop/1.0 | arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Terminate/1.0 | arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Reboot/1.0

Type: array of Strings

Array Members: Maximum number of 5 items.

Length Constraints: Minimum length of 1. Maximum length of 1024.

Required: No

AlarmDescription

The description for the alarm.

Type: String

Length Constraints: Minimum length of 0. Maximum length of 1024.

Required: No

AlarmName

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

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Required: Yes

ComparisonOperator

The arithmetic operation to use when comparing the specified statistic and threshold. The specified statistic value is used as the first operand.

Type: String

Valid Values: GreaterThanOrEqualToThreshold | GreaterThanThreshold | LessThanThreshold | LessThanOrEqualToThreshold

Required: Yes

Dimensions.member.N

The dimensions for the metric associated with the alarm.

Type: array of Dimension objects

Array Members: Maximum number of 10 items.

Required: No

EvaluationPeriods

The number of periods over which data is compared to the specified threshold.

Type: Integer

Valid Range: Minimum value of 1.

Required: Yes

ExtendedStatistic

The percentile statistic for the metric associated with the alarm. Specify a value between p0.0 and p100.

Type: String

Pattern: p(\d{1,2}(\.\d{0,2})?|100)

Required: No

InsufficientDataActions.member.N

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).

Valid Values: arn:aws:automate:region:ec2:stop | arn:aws:automate:region:ec2:terminate | arn:aws:automate:region:ec2:recover

Valid Values (for use with IAM roles): arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Stop/1.0 | arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Terminate/1.0 | arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Reboot/1.0

Type: array of Strings

Array Members: Maximum number of 5 items.

Length Constraints: Minimum length of 1. Maximum length of 1024.

Required: No

MetricName

The name for the metric associated with the alarm.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Required: Yes

Namespace

The namespace for the metric associated with the alarm.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [^:].*

Required: Yes

OKActions.member.N

The actions to execute when this alarm transitions to an OK state from any other state. Each action is specified as an Amazon Resource Name (ARN).

Valid Values: arn:aws:automate:region:ec2:stop | arn:aws:automate:region:ec2:terminate | arn:aws:automate:region:ec2:recover

Valid Values (for use with IAM roles): arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Stop/1.0 | arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Terminate/1.0 | arn:aws:swf:us-east-1:{customer-account}:action/actions/AWS_EC2.InstanceId.Reboot/1.0

Type: array of Strings

Array Members: Maximum number of 5 items.

Length Constraints: Minimum length of 1. Maximum length of 1024.

Required: No

Period

The period, in seconds, over which the specified statistic is applied.

Type: Integer

Valid Range: Minimum value of 60.

Required: Yes

Statistic

The statistic for the metric associated with the alarm, other than percentile. For percentile statistics, use ExtendedStatistic.

Type: String

Valid Values: SampleCount | Average | Sum | Minimum | Maximum

Required: No

Threshold

The value against which the specified statistic is compared.

Type: Double

Required: Yes

Unit

The unit of measure for the statistic. For example, the units for the Amazon EC2 NetworkIn metric are Bytes because NetworkIn tracks the number of bytes that an instance receives on all network interfaces. You can also specify a unit when you create a custom metric. Units help provide conceptual meaning to your data. Metric data points that specify a unit of measure, such as Percent, are aggregated separately.

If you specify a unit, you must use a unit that is appropriate for the metric. Otherwise, the Amazon CloudWatch alarm can get stuck in the INSUFFICIENT DATA state.

Type: String

Valid Values: Seconds | Microseconds | Milliseconds | Bytes | Kilobytes | Megabytes | Gigabytes | Terabytes | Bits | Kilobits | Megabits | Gigabits | Terabits | Percent | Count | Bytes/Second | Kilobytes/Second | Megabytes/Second | Gigabytes/Second | Terabytes/Second | Bits/Second | Kilobits/Second | Megabits/Second | Gigabits/Second | Terabits/Second | Count/Second | None

Required: No

Errors

For information about the errors that are common to all actions, see Common Errors.

LimitExceeded

The quota for alarms for this customer has already been reached.

HTTP Status Code: 400