Which combination of steps will meet these requirements?
(Choose three.)
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.
Use an Elastic Load Balancer to distribute traffic across multiple EC2 instances. Ensure that the EC2 instances are configured in unlimited mode.
Modify the DB instance to create a read replica in the same Availability Zone. Promote the read replica to be the primary DB instance in failure scenarios.
Modify the DB instance to create a Multi-AZ deployment that extends across two Availability Zones.
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.
Explanations:
Distributing traffic across multiple EC2 instances with an Elastic Load Balancer and Auto Scaling group provides redundancy and automatic recovery in case of an instance failure. This setup ensures high availability for the application layer.
Configuring EC2 instances in unlimited mode can handle sudden traffic spikes, but it does not provide automatic recovery or redundancy as it only removes CPU credit limits.
Creating a read replica provides a backup for read-heavy workloads, but it does not provide automatic failover. In failure scenarios, manually promoting the replica causes additional downtime.
Modifying the RDS instance to a Multi-AZ deployment ensures automatic failover to another Availability Zone in the event of a failure, minimizing downtime for the database layer.
Creating a replication group with Auto Scaling for ElastiCache is not possible. ElastiCache clusters do not use Auto Scaling groups. Instead, setting up a Redis replication group with Multi-AZ can provide automatic failover.