DOP-C02 Question 149
Select 3Your company has a multi-tier application hosted on AWS that uses an Application Load Balancer (ALB) in front of an Auto Scaling group of EC2 instances, an RDS database, and an S3 bucket for storage. The application has a Service Level Agreement (SLA) promising 99.9% availability to its customers. As a DevOps engineer, how should you architect the environment to meet or exceed the SLA while minimizing costs?
- A
Enable Multi-AZ deployments for the RDS database to ensure high availability.
- B
Configure the Auto Scaling group to span multiple Availability Zones.
- C
Use a provisioned S3 bucket with versioning enabled to maintain high availability.
- D
Deploy a backup ALB in a secondary region and configure Route 53 for failover routing.
- E
Set up AWS Backup for the RDS database and enable daily snapshots.
Show answer and explanation
Correct answers: A, B, D
Explanation
To meet a 99.9% SLA, it is critical to ensure high availability across all layers of your architecture. Multi-AZ RDS deployments and Auto Scaling groups spanning multiple AZs provide fault tolerance at the database and application tiers. Additionally, deploying a backup ALB in a secondary region with failover routing ensures resilience in the event of a regional outage. These measures collectively help achieve the desired SLA while minimizing costs.
- A. Correct.
Enabling Multi-AZ deployments for RDS ensures high availability for the database layer by automatically failing over to a standby instance in another Availability Zone during outages, which is essential for meeting the SLA.
- B. Correct.
Configuring the Auto Scaling group to span multiple Availability Zones ensures that application instances are distributed across zones, reducing the likelihood of downtime caused by a single AZ failure.
- C. Incorrect.
While versioning can help with data recovery, it does not directly contribute to availability or SLA adherence. S3 already provides high availability by default, so additional configuration is unnecessary in this context.
- D. Correct.
Using a backup ALB in a secondary region with Route 53 failover ensures that traffic can be rerouted to an alternate region in case of a regional outage, contributing to meeting or exceeding the SLA.
- E. Incorrect.
AWS Backup and daily snapshots improve data durability and recovery but do not directly impact availability or SLA adherence for the live system.