Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 297 discussion

Just create an auto scaling policy

I picked B.. I am not 100% sure..The application is deployed in 5 instances initially. What is the logic behind 2/3/6 ASG. Because utilization is 10%, we can set min 2? I know for sure I am not going to get this ASG question correct in the exam.

The correct answer is B. This solution will meet the requirements because it will: Automate the scalability of the application by using EC2 Auto Scaling. Optimize the cost of the architecture by only scaling the number of EC2 instances up when needed. Ensure that the application has enough CPU resources when surges occur by setting the target value of the target tracking scaling policy to 50%.

Wrong answers: Options A, C, and D are not the most appropriate solutions: Option A suggests creating a CloudWatch alarm to terminate an EC2 instance when CPU utilization is less than 20%. However, this approach does not ensure that the application will have enough CPU resources during surges, as it only terminates instances when CPU utilization is low, which may not meet the requirements. Option C suggests creating an Auto Scaling group without any specific scaling policies or configurations. This approach does not address the need for automated scaling based on CPU utilization, making it insufficient for the given requirements. Option D suggests using CloudWatch alarms to send notifications via Amazon SNS and manually adjusting the number of instances based on the received messages. This approach lacks automation and requires manual intervention, which does not optimize cost or meet the requirement of automated scalability. Therefore, Option B is the most appropriate solution in this case.

Explanation: Option B leverages EC2 Auto Scaling, which is designed to automatically adjust the number of instances based on specified metrics. By setting a target tracking scaling policy based on average CPU utilization, the Auto Scaling group can dynamically scale the number of instances to maintain the desired level of CPU resources. The minimum instances of 2 ensure a minimum baseline capacity, while the desired capacity of 3 ensures at least three instances are running even during normal traffic. The maximum instances of 6 cap the upper limit to control costs.

Auto Scaling group must have an AMI for it.

how can we set max to 6 since the company is using 5 ec2 instance

Reasons: • An Auto Scaling group will automatically scale the EC2 instances to match changes in demand. This optimizes cost by only running as many instances as needed. • A target tracking scaling policy monitors the ASGAverageCPUUtilization metric and scales to keep the average CPU around the 50% target value. This ensures there are enough resources during CPU surges. • The ALB and target group are reused, so the application architecture does not change. The Auto Scaling group is associated to the existing load balancer setup. • A minimum of 2 and maximum of 6 instances provides the ability to scale between 3 and 6 instances as needed based on demand. • Costs are optimized by starting with only 3 instances (the desired capacity) and scaling up as needed. When CPU usage drops, instances are terminated to match the desired capacity.

as you dig down the question, they get more and more bogus with less and less votes

B is my vote

Based on the information given, the best solution is option"B". Autoscaling group with target tracking scaling policy with min 2 instances, desired capacity to 3, and the maximum instances to 6.

B is the correct solution because it allows for automatic scaling based on the average CPU utilization of the EC2 instances in the target group. With the use of a target tracking scaling policy based on the ASGAverageCPUUtilization metric, the EC2 Auto Scaling group can ensure that the target value of 50% is maintained while scaling the number of instances in the group up or down as needed. This will help ensure that the application has enough CPU resources during surges without overprovisioning, thus optimizing the cost of the architecture.

Should be B