Create an Alarm in CloudWatch

This alarm will be used in the dynamic scaling policy.

1. Go to CloudWatch console.
   Information noteNote: If you are not familiar with AWS CloudWatch, please have a look at AWS documentation at https://aws.amazon.com/cloudwatch/.
2. Click Alarms > Create Alarm to open the Create Alarm form.
3. Click Per-Lb Metrics.

   

   A list of metrics is displayed for all existing AWS Elastic Load Balancers.
4. In Select Metric, choose the RequestCount metric from the load-balancer ELB-Talend-ESB.

   

5. In Define Alarm, use the following information:

   Field	Value
   Name	HighRequestCountAlarm
   Description	RequestCount too high
   Whenever	RequestCount >= 60
   For ... consecutive period(s)	2
   Period	1 Minute
   Send notification to	Click New list and type Topic_HighRequestCountAlarm.
   Email list	Put your valid email to receive email notifications.

   The form should look like this:

   

6. Click Create Alarm.
   Information noteNote: Once created, the Alarm is in the state Insufficient Data. This means CloudWatch does not have enough data yet to evaluate the Alarm. You can change this by generating some activity.

   For example, a tool like Soapui or any other REST or HTTP client could be used to invoke multiple times our application url through the load balancer.

   In your case, this url looks like this: http://elb-talend-esb-1328119247.eu-west-1.elb.amazonaws.com:8040/services. After a few moment, your alarm should change of status from Insufficient Data to OK or Alarm, depending on the defined threshold.

   

   The Alarm will raise when Request Count is higher than 60 during 2 minutes.