A bank's Application Load Balancer 5xx rate jumped in one Region while the same application in another Region stayed steady and instance CPU looked normal. AWS Health Dashboard has an open event for the load balancing service in the affected Region. What should operators do before they rebuild the fleet?
Select an answer to reveal the explanation.
Short Explanation
When the building posts a notice that the elevators are out, you read the notice before you remodel every floor. AWS Health is that notice for the load balancer, and the other Region being fine fits a regional service event. Replacing AMIs does not repair the service AWS already flagged.
Full Explanation
AWS Health Dashboard reports events in AWS services that affect the account. An open load-balancing event in the same Region as the 5xx rise, with normal CPU and a healthy second Region, is the explanation to follow before a rebuild. New AMIs change the instances, which the symptoms do not implicate, and a fleet refresh during a load-balancer event adds risk. Failing over the database to a read replica moves the data tier the stem does not show as sick, and a replica promotion is not the remedy for a load-balancer service event. Deleting alarms hides the symptom and leaves the event untouched. Caveat: a Health event does not prove every 5xx is AWS; if the event clears and 5xx remains, return to target health and application logs. Operational check: open the Health event, note the affected service and Region, and compare the 5xx graph to the event start time before any launch template change.