An application consists of the following architecture: a.
EC2 Instances in a single AZ behind an ELB b.
A NAT Instance which is used to ensure that instances can download updates from the Internet What could be done to ensure better fault tolerance in this setup? (SELECT TWO.)
Click on the arrows to vote for the correct answer
A. B. C. D.Correct Answer - B and C.
AWS Documentation mentions the following:
Adding Auto Scaling to your application architecture is one way to maximize the benefits of the AWS Cloud.
When you use Auto Scaling, your applications gain the following benefits:
Better fault tolerance.
Auto Scaling can detect when an instance is unhealthy.
Then it terminates that instance, and launches an instance to replace it.
You can also configure Auto Scaling to use multiple Availability Zones.
If one Availability Zone becomes unavailable, Auto Scaling can launch instances in another one to compensate.
Better availability.
Auto Scaling can help you ensure that your application always has the right amount of capacity to handle the current traffic demands.
For more information on the benefits of Auto Scaling, please visit the following URL:
https://docs.aws.amazon.com/autoscaling/ec2/userguide/auto-scaling-benefits.htmlIn this architecture, the application is running on EC2 instances behind an Elastic Load Balancer (ELB) in a single Availability Zone (AZ). Additionally, a NAT instance is used to allow instances to download updates from the Internet. The challenge with this setup is that if the Availability Zone goes down, the application will become unavailable. To improve fault tolerance, two potential solutions can be implemented:
Add more instances in another Availability Zone: One approach to improve fault tolerance is to launch more EC2 instances in another Availability Zone. This ensures that if the primary Availability Zone goes down, the application can still function from the secondary Availability Zone. In addition, by distributing instances across multiple AZs, you can increase application availability and reduce the risk of a single point of failure.
Add an Auto Scaling Group to the setup: Another solution is to use an Auto Scaling group to launch additional EC2 instances automatically based on predefined policies. Auto Scaling can help maintain the desired capacity by automatically launching new instances in response to changes in demand, ensuring the application is always available. By using an Auto Scaling group, you can ensure that the number of instances is sufficient to handle traffic and that new instances are launched when needed, and that instances are terminated when demand decreases.
Therefore, the correct answers are:
A. Add more instances in another Availability Zone. B. Add an Auto Scaling Group to the setup.