CloudWatch 警报操作仅触发一次 SNS

Question

I have a CloudWatch alarm created for testing purposes. It checks the number of bytes read on a Kinesis Stream. If less than 1 bytes are received within 1 minute, it triggers alarm and send email via SNS. So, I get email after 1 min, but then after that I don't get any further email. Is it right the email notification sent only once? In my test data is not flowing all the time. So, ideally, it should send email every minute. Correct?

Answer 1

If CloudWatch alarm switched to ALARM state after specified period (1 minute), then in your case it means it received less than 1 byte. When switched, it will trigger configured actions (in your case it is email notification). As long as alarm remains in the ALARM state without switching it state back to OK , nothing will be triggered again.

if alarm returned back to OK state and then again after the specified period it switched to ALARM , configured action will be triggered again.

For more information, refer to documentation .

Answer 2

Whether or not the action keeps firing depends on the type of action .

SNS actions only trigger once when the state changes to ALARM . Other actions such as EC2 auto scaling keep triggering as long as the alarm is in ALARM state.

If your alarm reverts to OK state and then back again to ALARM , SNS will get triggered again.

AWS docs