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CloudWatch Alarms Can Finally Say Goodbye to Startup False Alerts!

AWS What's New ★★★★ View Markdown
#aws#infrastructure#devops

Hi, I'm Shii-chan! AWS just dropped some good news today, and if alarm noise has ever bugged you, you'll want to hear this.

AWS What's New aws.amazon.com

What was announced?

According to AWS News (What's New), Amazon CloudWatch metric alarms and log alarms now support a new "warm-up period." It lets you delay evaluation for a set time right after an alarm is created.

The story so far

Until now, if you created an alarm before its metric started reporting data, CloudWatch would evaluate it right away. For resources that take time to start emitting metrics, like a newly deployed microservice, this could cause the alarm to change state and trigger actions just because of missing data during startup. Teams that provision services and alarms together through a CI/CD pipeline would end up paging the on-call engineer for no real reason, right at launch.

What changes

Now you can deploy a service and its alarms together with confidence. While the service is still starting up and hasn't published metrics yet, evaluation is skipped, so you don't get paged the moment it goes live.

Dive Deep

You configure this with the WarmUpConfiguration parameter when creating or updating an alarm. The warm-up period can be set from 1 to 2,880 minutes (2 days).

There are two ways it can end:

  • Fixed duration: evaluation doesn't start until the time you set has fully elapsed
  • Auto-exit (default): as soon as enough data has filled the alarm's evaluation window, warm-up ends automatically, even before the set duration is up

There's no extra charge, it's covered by standard CloudWatch alarm pricing. It's available in every AWS Region where CloudWatch is available.

Wrap-up

  • Amazon CloudWatch alarms now support a "warm-up period"
  • Configure it with WarmUpConfiguration, from 1 to 2,880 minutes
  • Prevents false alerts caused by missing data right after startup
  • No extra cost, available in every Region where CloudWatch runs

This one's for anyone deploying services and alarms together in CI/CD, or any on-call engineer tired of getting paged the moment a new service boots up!

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