Question-1: You are working in an online eLearning company, where you publish your training material, exam preparation material and other live scoring calculations etc. You have seen recently load on your application had increased because number of students are increasing to your website and most of the user use your website from North America, hence traffic is higher during New York day time. You already setup EC2 auto scaling group with the 3 minimum EC2 instance. And you have also configured auto-scaling policy such that if CPU utilization increases 80% for 5 minutes you will add another EC2 instance in auto-scaling group. However, still user are seeing performance issue on the website and online random exam is not properly loaded. Which of the following may not be good solution for keeping the cost in mind?

1. You will increase the monitoring for EC2 instance CPU utilization for detailed monitoring.
2. You will setup minimum EC2 instances to 5 in auto-scaling group.
3. You will even monitor the CPU for 10 minutes.
4. You will decrease the CPU utilization policy from 80% to 50%

Correct Answer  : B

Detailed Explaination: There are various ways by which you can maintain the number of EC2 instance at proper level like looking at CPU utilization, or having detailed monitoring etc.

However, question focus is that it should not increase the cost very high. In the given option there are two option which can increase the overall price Option-1 and Option-2. If you enable detailed monitoring than cost will increase because detailed monitoring has cost associated with it, which provides each EC2 instance detailed monitoring every minute and by default you will get minoring every 5 minute, which is free.

Now another option is option-2 which says increase the minimum instance in EC2 group to 5. It means you will always have 5 instance running in that group. Whatever is the CPU utilization?

So if we consider both the option then option-2 is more costly than option-1. Hence, we will say designing solution based on option-2 is not good if you want to minimize the overall cost.