Which action will meet this requirement?
Reregister the failed instances with the ALB.
Enable all Availability Zones for the ALB.
Use the instance refresh feature to redeploy the EC2 Auto Scaling group.
Restart the EC2 instances that are not receiving traffic.
Explanations:
Reregistering the instances with the ALB won’t solve the issue because the instances are already registered, and the problem likely lies in the configuration, not the registration itself.
Enabling all Availability Zones for the ALB will ensure that the load balancer routes traffic to instances in all enabled AZs. If certain AZs are disabled, some instances may not receive traffic.
Using the instance refresh feature will only redeploy instances but doesn’t address the issue of unbalanced traffic distribution between AZs or an improperly configured load balancer.
Restarting the EC2 instances won’t fix the issue if the root cause is related to the load balancer or Availability Zone settings. Simply restarting the instances will not resolve the traffic distribution problem.
In my experience, the answer is:
Enable all Availability Zones for the ALB.