Increase Scalability and Availability

Correct Answer: A and B.

The AWS Documentation mentions the following.

Amazon EC2 Auto Scaling helps you ensure that you have the correct number of Amazon EC2 instances available to handle your application load.

You create collections of EC2 instances, called Auto Scaling groups.

You can specify the minimum number of instances in each Auto Scaling group, and Amazon EC2 Auto Scaling ensures that your group never goes below this size.

You can specify the maximum number of instances in each Auto Scaling group, and Amazon EC2 Auto Scaling ensures that your group never goes above this size.

Amazon RDS Multi-AZ deployments provide enhanced availability and durability for Database (DB) Instances, making them a natural fit for production database workloads.

When you provision a Multi-AZ DB Instance, Amazon RDS automatically creates a primary DB Instance and synchronously replicates it to a standby instance in a different Availability Zone (AZ)

Option C is incorrect since the NAT gateway is preferred for better scalability and availability.

Option D is incorrect since the Load balancer should be used for distributing traffic.

For more information on EC2 Autoscaling and RDS Multi-AZ, please refer to the below URLs-

https://docs.aws.amazon.com/autoscaling/ec2/userguide/what-is-amazon-ec2-auto-scaling.html https://aws.amazon.com/rds/details/multi-az/

The two options that can be used to increase the scalability and availability of the application are:

A. Launch the EC2 Instances as part of an Autoscaling Group: By launching EC2 instances as part of an autoscaling group, the application can automatically scale based on the incoming traffic. Autoscaling group ensures that a desired number of instances are always available to handle the incoming requests. When the demand for the application increases, the autoscaling group can automatically launch additional EC2 instances. Conversely, when the demand decreases, it can automatically terminate the instances. This helps in optimizing the application performance and reducing the costs by automatically scaling the infrastructure.

B. Enable Multi-AZ for the database: Enabling Multi-AZ (Availability Zone) for the database helps in increasing the availability of the database. In Multi-AZ, the database is replicated across multiple availability zones, which ensures that in case of an outage in one availability zone, the database is still available in another availability zone. Multi-AZ helps in reducing the downtime and maintaining the continuity of the application by automatically failing over to the secondary database instance in case of a primary database failure.

The other options given in the question are:

C. Use a NAT Instance instead of a NAT gateway: A NAT gateway is a highly available managed service provided by AWS, which is specifically designed for NATing traffic from private subnets to the Internet. Using a NAT instance instead of a NAT gateway may not provide the same level of availability and scalability as a NAT gateway. NAT instances need to be manually managed, and in case of a failure, they need to be replaced or restarted manually. On the other hand, NAT gateways are highly available and can automatically scale based on the traffic.

D. Use Route 53 instead of the Load balancer: Route 53 is a DNS service provided by AWS, which can be used for routing traffic to different resources based on the routing policies. However, using Route 53 instead of a load balancer may not provide the same level of scalability and availability as a load balancer. Load balancers are specifically designed for distributing traffic to multiple instances and ensuring that the application can handle the incoming requests. Load balancers also provide health checks to ensure that the instances are healthy before routing the traffic to them. Using Route 53 alone may not be sufficient to ensure the availability and scalability of the application.