AWS Certified Solutions Architect – Associate (SAA-C03)Design Cost-Optimized ArchitecturesEasy
A startup is deploying a new web application on AWS that uses a fleet of Amazon EC2 instances behind an Application Load Balancer. The application experiences predictable daily traffic spikes between 9 AM and 5 PM, but very low traffic outside these hours. They want to ensure sufficient capacity during peak times and scale down to minimize costs during off-peak hours, without manual intervention. Which AWS Auto Scaling feature should be used?
- AStep Scaling
- BScheduled Scaling
- CSimple Scaling
- DTarget Tracking Scaling
Show answer & explanationAnswer & explanation
Correct answer: B. Scheduled Scaling
Scheduled Scaling allows you to set specific times for Auto Scaling to scale your capacity up or down based on predictable traffic patterns, making it ideal for daily spikes and low usage periods without manual intervention.
Why the other options are wrong
- A. Step Scaling allows you to define scaling adjustments that vary based on the size of the alarm breach, suitable for reactive scaling but not for proactive, time-based scaling of predictable events.
- C. Simple Scaling (now largely superseded by Step Scaling) adjusts capacity based on a single alarm threshold, which is less flexible for detailed scaling schedules.
- D. Target Tracking Scaling adjusts capacity to maintain a specific metric (e.g., CPU utilization) at a target value, which is good for unpredictable loads but less optimal for predictable, time-based patterns.
AWS Auto Scaling Scheduled Scaling
AWS Auto Scaling Scheduled Scaling allows you to adjust the desired capacity of your Auto Scaling group based on a predictable schedule.
- Ideal for predictable traffic patterns (e.g., daily, weekly spikes).
- Configured using cron expressions or specific dates/times.
- Ensures capacity is available when needed and scales down to save costs.
- Reduces manual intervention for known demand changes.
Memory trick: Scheduled Scaling: Set the Clock, Cut the Cost.