A CloudWatch alarm that already combines several metrics is maintained in this account. Route 53 should mark a health check unhealthy only when that alarm enters the ALARM state, and the health check should not probe any endpoint directly. What should be configured?
Show answer and explanation
Answer: B
Route 53 offers a health check type that reflects the state of a CloudWatch alarm. The health check becomes unhealthy when the alarm is in ALARM, and you choose how insufficient data should be treated. This suits conditions that an HTTP or TCP probe cannot express, such as a signal computed from several metrics. Endpoint checks probe a resource directly, and calculated checks aggregate other Route 53 health checks rather than reading alarm states.
Why the other options are wrong
- A. An HTTPS check only tests whether a URL responds. It cannot react to a CloudWatch alarm's state or to a condition built from several metrics.
- C. A TCP check confirms that a port accepts connections. It cannot express a condition defined by an alarm, so the required trigger would be missed.
- D. A calculated check combines the results of other Route 53 health checks. It does not read CloudWatch alarm states directly, so it does not satisfy the requirement.