Questions 10 to 12

Question 10

A company’s web application is using multiple Amazon EC2 Linux instances and stores data on Amazon EBS volumes. The company is looking for a solution to increase the resiliency of the application in case of a failure. What should a solutions architect do to meet these requirements?

1. Launch the application on EC2 instances in each Availability Zone. Attach EBS volumes to each EC2 instance.
2. Create an Application Load Balancer with Auto Scaling groups across multiple Availability Zones. Mount an instance store on each EC2 instance.
3. Create an Application Load Balancer with Auto Scaling groups across multiple Availability Zones. Store data on Amazon EFS, and mount a target on each instance.
4. Create an Application Load Balancer with Auto Scaling groups across multiple Availability Zones. Store data using Amazon S3 One Zone-Infrequent Access (S3 One Zone-A).

Correct Answer: 3

Explanation: To increase the resiliency of the application, the solutions architect can use Auto Scaling groups to launch and terminate instances across multiple Availability Zones based on demand. An Application Load Balancer (ALB) can be used to direct traffic to the web application running on the EC2 instances. Lastly, the Amazon Elastic File System (EFS) can assist with increasing the resiliency of the application by providing a shared file system that can be mounted by multiple EC2 instances from multiple Availability Zones.

INCORRECT: “Launch the application on EC2 instances in each Availability Zone. Attach EBS volumes to each EC2 instance.” is incorrect as the EBS volumes are single points of failure that are not shared with other instances.

INCORRECT: “Create an Application Load Balancer with Auto Scaling groups across multiple Availability Zones. Mount an instance store on each EC2 instance.” is incorrect as instance stores are ephemeral data stores, which means data is lost when powered down. Also, instance stores cannot be shared between instances.

CORRECT: “Create an Application Load Balancer with Auto Scaling groups across multiple Availability Zones. Store data on Amazon EFS, and mount a target on each instance.” is the correct answer.

INCORRECT: “Create an Application Load Balancer with Auto Scaling groups across multiple Availability Zones. Store data using Amazon S3 One Zone-Infrequent Access (S3 One Zone-IA).” is incorrect as there are data retrieval charges associated with this S3 tier. It is not a suitable storage tier for application files.

References:

https://docs.aws.amazon.com/efs/