Question

A user is planning to launch three EC2 instances behind a single Elastic Load Balancer. The deployment should be highly available.

A. Launch the instances across multiple Availability Zones in a single AWS Region.

B. Launch the instances as EC2 Spot Instances in the same AWS Region and the same Availability Zone.

C. Launch the instances in multiple AWS Regions, and use Elastic IP addresses.

D. Launch the instances as EC2 Reserved Instances in the same AWS Region, but in different Availability Zones.

Answer 1

The correct answer is A. “Launch the instances across multiple Availability Zones in a single AWS Region.”

Explanation:

To make the deployment highly available the user should launch the instances across multiple Availability Zones in a single AWS Region. Elastic Load Balancers can only serve targets in a single Region so it is not possible to deploy across Regions.

B. “Launch the instances as EC2 Spot Instances in the same AWS Region and the same Availability Zone” is incorrect. The pricing model is not relevant to high availability and deploying in a single AZ does not result in a highly available deployment.

C. “Launch the instances in multiple AWS Regions, and use Elastic IP addresses” is incorrect. You cannot use an ELB with instances in multiple Regions and using an EIP does not help.

D. “Launch the instances as EC2 Reserved Instances in the same AWS Region, but in different Availability Zones” is incorrect. Using reserved instances may not be appropriate as we do not know whether this is going to be a long-term workload or not.