Create CloudWatch alarms for Amazon EC2 instances that fail status checks - Amazon Elastic Compute Cloud
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Create CloudWatch alarms for Amazon EC2 instances that fail status checks

You can use the status check metrics to create CloudWatch alarms to notify you when an instance has a failed status check.

Important

Status checks and status check alarms can temporarily enter an insufficient data state if there are missing metric data points. Although rare, this can happen when there is an interruption in the metric reporting systems, even when an instance is healthy. We recommend that you treat this state as missing data instead of a status check failure or alarm breach, especially when taking stop, terminate, reboot, or recover actions on the instance in response.

To create a status check alarm, use one of the following methods:

Console

Use the following procedure to configure an alarm that sends you a notification by email, or stops, terminates, or recovers an instance when it fails a status check.

To create a status check alarm

  1. Open the Amazon EC2 console at https://console.amazonaws.cn/ec2/.

  2. In the navigation pane, choose Instances.

  3. Select the instance, choose the Status Checks tab, and choose Actions, Create status check alarm.

  4. On the Manage CloudWatch alarms page, under Add or edit alarm, choose Create an alarm.

  5. For Alarm notification, turn the toggle on to configure Amazon Simple Notification Service (Amazon SNS) notifications. Select an existing Amazon SNS topic or enter a name to create a new topic.

    If you add an email address to the list of recipients or created a new topic, Amazon SNS sends a subscription confirmation email message to each new address. Each recipient must confirm the subscription by choosing the link contained in that message. Alert notifications are sent only to confirmed addresses.

  6. For Alarm action, turn the toggle on to specify an action to take when the alarm is triggered. Select the action.

  7. For Alarm thresholds, specify the metric and criteria for the alarm.

    You can leave the default settings for Group samples by (Average) and Type of data to sample (Status check failed:either), or you can change them to suit your needs.

    For Consecutive period, set the number of periods to evaluate and, in Period, enter the evaluation period duration before triggering the alarm and sending an email.

  8. (Optional) For Sample metric data, choose Add to dashboard.

  9. Choose Create.

If you need to make changes to an instance status alarm, you can edit it.

To edit a status check alarm

  1. Open the Amazon EC2 console at https://console.amazonaws.cn/ec2/.

  2. In the navigation pane, choose Instances.

  3. Select the instance and choose Actions, Monitoring, Manage CloudWatch alarms.

  4. On the Manage CloudWatch alarms page, under Add or edit alarm, choose Edit an alarm.

  5. For Search for alarm, choose the alarm.

  6. When you are finished making changes, choose Update.

Command line

In the following example, the alarm publishes a notification to an SNS topic, arn:aws-cn:sns:us-west-2:111122223333:my-sns-topic, when the instance fails either the instance check or system status check for at least two consecutive periods. The CloudWatch metric used is StatusCheckFailed.

To create a status check alarm using the Amazon CLI

  1. Select an existing SNS topic or create a new one. For more information, see Using the Amazon CLI with Amazon SNS in the Amazon Command Line Interface User Guide.

  2. Use the following list-metrics command to view the available Amazon CloudWatch metrics for Amazon EC2.

    aws cloudwatch list-metrics --namespace AWS/EC2

  3. Use the following put-metric-alarm command to create the alarm.

    aws cloudwatch put-metric-alarm \
--alarm-name StatusCheckFailed-Alarm-for-i-1234567890abcdef0 \
--metric-name StatusCheckFailed \
--namespace AWS/EC2 \
--statistic Maximum \
--dimensions Name=InstanceId,Value=i-1234567890abcdef0 \
--unit Count \
--period 300 \
--evaluation-periods 2 \
--threshold 1 \
--comparison-operator GreaterThanOrEqualToThreshold \
--alarm-actions arn:aws-cn:sns:us-west-2:111122223333:my-sns-topic

    The period is the time frame, in seconds, in which Amazon CloudWatch metrics are collected. This example uses 300, which is 60 seconds multiplied by 5 minutes. The evaluation period is the number of consecutive periods for which the value of the metric must be compared to the threshold. This example uses 2. The alarm actions are the actions to perform when this alarm is triggered. This example configures the alarm to send an email using Amazon SNS.