Q19 — AWS SAP-C02 Ch.1

Question 19 of 75 | ← Chapter 1

Q94. A company is hosting a critical application on a single Amazon EC2 instance. The application uses an Amazon ElastiCache for Redis single-node cluster for an in-memory data store. The application uses an Amazon RDS for MariaDB DB instance for a relational database. For the application to function, each piece of the infrastructure must be healthy and must be in an active state. A solutions architect needs to improve the application's architecture so that the infrastructure can automatically recover from failure with the least possible downtime. Which combination of steps will meet these requirements? (Select THREE.)

• A. Use an Elastic Load Balancer to distribute traffic across multiple EC2 instances. Ensure that the EC2 instances are part of an Auto Scaling group that has a minimum capacity of two instances. ✓
• B. Use an Elastic Load Balancer to distribute traffic across multiple EC2 instances. Ensure that the EC2 instances are configured in unlimited mode.
• C. Modify the DB instance to create a read replica in the same Availability Zone. Promote the read replicato be the primary DB instance in failure scenarios.
• D. Modify the DB instance to create a Multi-AZ deployment that extends across two Availability Zones. ✓
• E. Create a replication group for the ElastiCache for Redis cluster. Configure the cluster to use an Auto Scaling group that has a minimum capacity of two instances.
• F. Create a replication group for the ElastiCache for Redis cluster. Enable Multi-AZ on the cluster. ✓

Correct Answer: A. Use an Elastic Load Balancer to distribute traffic across multiple EC2 instances. Ensure that the EC2 instances are part of an Auto Scaling group that has a minimum capacity of two instances., D. Modify the DB instance to create a Multi-AZ deployment that extends across two Availability Zones., F. Create a replication group for the ElastiCache for Redis cluster. Enable Multi-AZ on the cluster.

Explanation

The combination of steps that will improve the application's architecture to automatically recover from failure with the least possible downtime are: A. Use an Elastic Load Balancer to distribute traffic across multiple EC2 instances. Ensure that the EC2 instances are part of an Auto Scaling group that has a minimum capacity of two instances. D. Modify the DB instance to create a Multi-AZ deployment that extends across two Availability Zones. F. Create a replication group for the ElastiCache for Redis cluster. Enable Multi-AZ on the cluster. Explanation: Option A: Using an Elastic Load Balancer (ELB) to distribute traffic across multiple EC2 instances is a common practice for achieving high availability and fault tolerance. By configuring the EC2 instances to be part of an Auto Scaling group with a minimum capacity of two instances, the infrastructure can automatically recover from failures by replacing unhealthy instances and maintaining the desired capacity. Option D: Modifying the DB instance to create a Multi-AZ deployment that spans two Availability Zones provides automatic failover capability. In the event of a failure in one Availability Zone, Amazon RDS automatically fails over to the standby replica in the other Availability Zone, minimizing downtime. Option F: Creating a replication group for the ElastiCache for Redis cluster and enabling Multi-AZ on the cluster enhances the availability and durability of the cache. With Multi-AZ enabled, the replication group is replicated across two Availability Zones, allowing for automatic failover in the event of a failure. Option B is incorrect because configuring the EC2 instances in unlimited mode does not provide the necessary fault tolerance and high availability. It only affects the billing behavior of the instances. Option C is incorrect because creating a read replica in the same Availability Zone and promoting it to the primary DB instance in failure scenarios does not provide automatic failover capability. It requires manual intervention to promote the replica. Option E is incorrect because configuring an Auto Scaling group for ElastiCache for Redis does not provide automatic failover capability. It only helps with scaling the cache cluster based on demand. Therefore, the correct combination of steps is A, D, and F.