An ALB shows more 5xx responses while its targets also become unhealthy.
Reduce duplicate notifications and handle the condition as one incident.
Which feature is most appropriate?
Use a CloudWatch composite alarm to combine the states of child alarms with a logical condition.
Detailed explanation
Notify when both the ALB 5xx and unhealthy-target alarms are in ALARM, while retaining each child's detection.
Notify when both the ALB 5xx and unhealthy-target alarms are in ALARM, while retaining each child's detection.
Visualization alone does not combine ALARM states and send automated notifications.
Visualization alone does not combine ALARM states and send automated notifications.
OR is satisfied by either alarm. Requiring both uses AND.
OR is satisfied by either alarm. Requiring both uses AND.
Either signal can notify separately, failing the simultaneous-condition and notification-consolidation requirements.
Either signal can notify separately, failing the simultaneous-condition and notification-consolidation requirements.
Check official documentation
Compare the following points with the official documentation.
Review composite alarm rule expressions and supported actions.
Official references
What to confirm
Use AND for simultaneous child states and centralize SNS notification.
Key points
- Composite alarm
- Child alarm
- Logical condition
Notes
- Environment: AWS SOA-C03 exam guide and the linked AWS documentation
- Reviewed against the linked AWS documentation on 2026-10-03.
Foundation review
Evaluate alarm states
ALARM("Alb5xx") AND ALARM("UnhealthyTargets") combines child states, rather than directly adding metric values.
Consolidate notifications
Keep detection in the child alarms and attach SNS notification to the composite. Composite alarms cannot directly perform EC2 or Auto Scaling actions.