Create Alarm

You can create a CloudWatch alarm that monitors CloudWatch metrics for a given AWS service. CloudWatch will automatically send you a notification when the metric reaches a threshold you specify.

In this section you will create an alarm that monitors the amount of traffic received by an EC2 instance and sends an email notification if a threshold is breached.

1. In the CloudWatch console navigate to All alarms and click on Create alarm

   

2. Click Select metric

   

3. Click on EC2

   

4. Click on Per-instance Metrics

   

5. Enter NetworkIn in the search box and hit enter.

   

6. Select the checkbox for VPC B Private AZ1 Server and click Select metric

   

7. In the resulting Specify metric and conditions screen change the Statistic and Period fields to Maximum and 1 minute respectively.

   

8. In the Conditions section below, enter a threshold value of 1000000 and click Next

   

9. In the Configure actions screen click on Add notification

   

10. Select Create new topic, enter NetworkingWorkshopAlarmTopic as the name, enter your email and click Create topic

    

11. Scroll to the bottom of the page, click Next and on the resulting screen

    • Enter NetworkingWorkshopAlarm as the Alarm name
    • Click Next

    

12. Review the values on the Preview and create screen and click Create alarm

    

13. The alarm will be created but the "State" of the alarm may show "Insufficient data". This will happen until enough data points are received by the alarm.

    

14. Under Actions there will be a warning for "Pending confirmation" which means that you have not confirmed the email subscription to SNS yet.

    

15. Go into your email, open the new message from "AWS Notifications" and confirm the subscription. This will be required to ensure you receive the notification.

    

In the next section you will get the opportunity to trigger the alarm and test the notification that you configured.