DOP-C02 practice question: EC2 Auto Scaling (policies, lifecycle hooks, warm pools) (2 of 2)
Resilient Cloud Solutions A free question from our original DOP-C02 practice exam. Try it, then open the answer to see why each option is right or wrong.
An online retailer runs its storefront on an Auto Scaling group of EC2 instances behind an Application Load Balancer. Traffic is steady most days but rises sharply when a flash sale starts at a fixed time every Tuesday at noon.
Last month the group scaled out only after CPU rose, so the first ten minutes of the sale produced timeouts while new instances started. The team wants capacity in place before the sale begins and wants normal daily traffic to follow demand.
The team wants to keep the existing policies and adjust only what is needed.
Which change meets these requirements?
Choose one answer.
AA. Keep the CPU target tracking policy, and add a scheduled action that raises the minimum capacity before noon every Tuesday and lowers it after the sale.
BB. Replace the target tracking policy with a step scaling policy that adds one instance each time CPU passes 50 percent, with a cooldown of 15 minutes between each step.
CC. Increase the group's maximum capacity to three times the current size, so that the group has room to grow when the sale starts.
DD. Set the group to use a simple scaling policy with a cooldown of 300 seconds on the instance count, so that each scale-out waits for the previous one to finish.
Show the answer and explanation
Answer: A
A. Right: Correct. The scheduled action puts capacity in place before the known sale start, and target tracking continues to follow demand during the rest of the week. The existing policy stays in place and only the schedule is added. Learn more: Scheduled scaling for Amazon EC2 Auto Scaling (opens in a new tab)
A scheduled scaling action raises the group's minimum capacity before a known event, so instances are running before the sale starts. Target tracking continues to adjust for ordinary daily demand. Step and simple policies react only after load rises, and a higher maximum does not start any instances on its own.
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