An Application Load Balancer spans two Availability Zones, and cross-zone load balancing is currently disabled on its target group. One zone has eight registered targets and the other has only two because an Auto Scaling event left the zones uneven. Operators see the two targets in the smaller zone running far hotter than the eight in the larger zone, because each Availability Zone receives an equal share of requests that is then divided among only the targets in that zone. The team wants every healthy target across both zones to receive a roughly equal share of requests regardless of how many targets each zone holds. Which configuration achieves this?
- AAttach the targets to a Network Load Balancer instead, because its per-flow hashing automatically equalises the request load across all targets in every Availability Zone by default.
- BRe-enable cross-zone load balancing on the target group so every request is distributed evenly across all healthy registered targets regardless of which zone each target is in. Correct
- CConfigure an Auto Scaling target tracking policy on CPU so the hotter zone gains instances, which over time evens out the target count between the two Availability Zones during peaks.
- DCreate a weighted target group routing rule that sends more traffic to the smaller zone, manually compensating for its lower target count so its instances stop running hotter than the rest.
Why A is wrong: Network Load Balancer disables cross-zone balancing by default, so it would still keep traffic within each zone and overload the two targets in the smaller zone just as the current setup does.
Why B is correct: Cross-zone load balancing spreads each request across all healthy targets in every zone, so the two targets in the smaller zone receive the same per-target share as the eight in the larger zone.
Why C is wrong: Scaling on CPU may add instances, but it does not change how the load balancer divides requests between zones, so the imbalance recurs whenever the zones drift apart in target count.
Why D is wrong: Manual weighting is brittle and breaks every time Auto Scaling changes the per-zone counts, so it cannot keep the per-target share equal as the fleet shifts the way cross-zone balancing does.