An application runs on EC2 instances behind an Application Load Balancer (ALB) across multiple Availability Zones. A misconfiguration in one AZ caused a partial outage. You need to test failover so the ALB avoids sending traffic to the failed AZ during a zonal shift. Which solution meets this requirement?

Disabling cross-zone load balancing on the ALB ensures that each ALB node only sends traffic to targets within its own Availability Zone. When a zonal shift is initiated using Amazon Route 53 Application Recovery Controller (ARC), it directs traffic away from the unhealthy AZ by updating DNS records. This combination effectively prevents the ALB from sending traffic to the failed AZ during a zonal shift. Disabling cross-zone load balancing on the ALB's target group is incorrect because cross-zone load balancing is configured at the ALB level, not the target group level for ALBs. Creating an ARC resource set referencing the ALB by its DNS hostname is incorrect because ARC zonal shifts operate on specific resources like ALBs, not just DNS hostnames. Referencing the ARN of the ALB's target group and using a readiness check is insufficient; a zonal shift must be explicitly initiated to redirect traffic.