Which solution will meet these requirements with the LEAST operational effort?
Place the EC2 instances in different AWS Regions. Use Amazon Route 53 health checks to redirect traffic. Use Aurora PostgreSQL Cross-Region Replication.
Configure the Auto Scaling group to use multiple Availability Zones. Configure the database as Multi-AZ. Configure an Amazon RDS Proxy instance for the database.
Configure the Auto Scaling group to use one Availability Zone. Generate hourly snapshots of the database. Recover the database from the snapshots in the event of a failure.
Configure the Auto Scaling group to use multiple AWS Regions. Write the data from the application to Amazon S3. Use S3 Event Notifications to launch an AWS Lambda function to write the data to the database.
Explanations:
Placing EC2 instances in different AWS Regions introduces higher latency and complexity due to inter-region communication and does not guarantee high availability within a single region. Cross-Region Replication adds operational overhead and is not necessary for a single AZ application requiring high availability.
Configuring the Auto Scaling group to use multiple Availability Zones enhances availability by distributing instances across AZs, mitigating the impact of an AZ failure. Multi-AZ for the database provides automatic failover, ensuring minimum downtime and data loss. Using RDS Proxy optimizes database connections, further enhancing performance and availability with minimal operational effort.
Using a single Availability Zone for the Auto Scaling group does not ensure high availability. Relying on hourly snapshots for recovery introduces significant downtime and potential data loss, making it unsuitable for a business-critical application.
Configuring the Auto Scaling group across multiple AWS Regions complicates the architecture and can lead to data consistency issues. Writing data to Amazon S3 and using Lambda to handle database updates adds complexity and potential delays, making it less efficient than other options for achieving high availability with minimal effort.
I measure that the answer is:
Configure the Auto Scaling group to use multiple Availability Zones. Configure the database as Multi-AZ. Configure an Amazon RDS Proxy instance for the database.