Amazon CloudWatch now supports warm-up periods for alarms

Amazon CloudWatch now allows configuring a warm-up period for metric and log alarms. This setting delays evaluation after alarm creation, reducing noise when metrics are not yet published, such as during new resource or service startup. For example, attaching a warm-up period to new microservices and alarms provisioned in a CI/CD pipeline prevents page notifications to on-call engineers while services are starting up or metrics are still being emitted. Previously, if underlying metrics had not started reporting data before an alarm was created, CloudWatch would immediately evaluate using the missing data handling setting, potentially triggering unnecessary notifications as newly deployed applications or services transitioned into alarm state during startup. The warm-up period addresses this issue by offering two options: waiting a set period before starting alarm evaluation, or automatically starting evaluation only after metrics meet the evaluation window. The warm-up period is set during alarm creation or update using the WarmUpConfiguration parameter and can be specified from 1 to 2,880 minutes (2 days). By default, alarms end warm-up early and start evaluation once sufficient data accumulates in the evaluation window. Alternatively, you can require alarms to wait the full duration before starting evaluation. The warm-up period is available at no additional cost in all AWS regions where Amazon CloudWatch is provided, beyond standard CloudWatch alarm charges. For details, see the Amazon CloudWatch User Guide sections on alarm warm-up periods and creating alarms that use warm-up periods.

Why it matters

This update is useful for developers and operations teams who want to prevent unnecessary alarm notifications when deploying new resources or services in the cloud environment.