Topic 1 Question 275
A company runs an internal browser-based application. The application runs on Amazon EC2 instances behind an Application Load Balancer. The instances run in an Amazon EC2 Auto Scaling group across multiple Availability Zones. The Auto Scaling group scales up to 20 instances during work hours, but scales down to 2 instances overnight. Staff are complaining that the application is very slow when the day begins, although it runs well by mid-morning.
How should the scaling be changed to address the staff complaints and keep costs to a minimum?
Implement a scheduled action that sets the desired capacity to 20 shortly before the office opens.
Implement a step scaling action triggered at a lower CPU threshold, and decrease the cooldown period.
Implement a target tracking action triggered at a lower CPU threshold, and decrease the cooldown period.
Implement a scheduled action that sets the minimum and maximum capacity to 20 shortly before the office opens.
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コメント(15)
- 正解だと思う選択肢: C
At first, I thought the answer is A. But it is C.
It seems that there is no information in the question about CPU or Memory usage. So, we might think the answer is A. why? because what we need is to have the required (desired) number of instances. It already has scheduled scaling that works well in this scenario. Scale down after working hours and scale up in working hours. So, it just needs to adjust the desired number to start from 20 instances.
But here is the point it shows A is WRONG!!! If it started with desired 20 instances, it will keep it for the whole day. What if the load is reduced? We do not need to keep the 20 instances always. That 20 is the MAXIMUM number we need, no the DESIRE number. So it is against COST that is the main objective of this question.
So, the answer is C
👍 10asoli2023/03/16 I would personally go for C, Implementing a target tracking scaling policy would allow the Auto Scaling group to adjust its capacity in response to changes in demand while keeping the specified metric at the target value https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-strategies.html
Option A is not the best solution because it sets the desired capacity to 20 shortly before the office opens, but it does not take into account the actual demand of the application. This means that the company will be paying for 20 instances all the time, even during the off-hours, which will result in unnecessary costs. Additionally, there may be days when the demand is lower or higher than expected, so it is not a scalable solution.
👍 3NolaHOla2023/02/17- 正解だと思う選択肢: C
Answer is C
👍 2zTopic2023/02/17
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