DOP-C02 Incident and Event Response Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Increase the health check interval to reduce load on instances

  Why it's wrong here

  Increasing the health check interval reduces how often the ELB sends health checks to each instance, which does lower the request load on the instances, but it also makes the ELB even slower to detect a failure once one occurs. The core problem here is that the current health check is validating the wrong thing—it does not verify the application's actual readiness—so the instance can remain unhealthy without ever tripping the check. Adjusting frequency cannot fix a detection-accuracy problem; it only changes how quickly the ELB reacts to a failure it is already designed to catch.

• ✓

  Configure a health check that checks a specific application endpoint

  Why this is correct

  Configuring a health check against a specific application endpoint, such as /healthz or /api/v1/status, makes the ELB perform a deep health check that exercises your application's critical request path, including framework routing, connections to dependent services, and session or cache state. This directly addresses the scenario where an instance accepts TCP or HTTP requests but is not truly ready to serve application traffic. By returning a non-200 status only when application dependencies or internal state are degraded, the ELB can accurately detect the unhealthy instance and stop sending it traffic.

• ✗

  Decrease the health check unhealthy threshold to 2

  Why it's wrong here

  Decreasing the unhealthy threshold only makes the ELB mark an instance unhealthy faster *after* it starts failing existing health checks. In this scenario, the problem is that the health check is not detecting the unhealthiness at all, rather than being too slow to react once a failure is detected. This change would not improve accuracy for an undetected issue. It is tempting as it appears to increase health check sensitivity. This setting is useful when instances fail predictably, and you require quicker removal from service, but not for detecting new types of failures.

• ✗

  Set the health check path to the root document ('/')

  Why it's wrong here

  Setting the health check path to '/' is a poor choice because the root document is often served by the web server or static file handler without invoking your application code at all, meaning it does not reflect the health of your business-critical logic. An instance could pass a root health check while its database connection pool is exhausted, authentication service is unreachable, or application process is deadlocked. This is a classic shallow health check that gives a false sense of availability, whereas the key is to target an endpoint that actually validates application health.

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