Interview Q&A / AWS & Cloud

1. How do an Auto Scaling group and a load balancer work together on AWS?

   An Auto Scaling group keeps the right number of healthy EC2 instances running, adding or removing them based on policies such as target CPU. A load balancer spreads incoming traffic across those instances in multiple AZs. The ASG registers new instances with the load balancer's target group and replaces any that fail health checks.

   AdvancedIn-depth4 min read
2. What is the difference between target tracking, step and scheduled scaling in an Auto Scaling group?

   Target tracking holds a metric near a value you set, like 50% CPU. Step scaling adds or removes capacity in sized steps based on alarm thresholds. Scheduled scaling changes capacity at set times for predictable load.

   IntermediateQuick answer1 min read
3. Can you use Spot Instances inside an Auto Scaling group, and how do you do it safely?

   Yes. A mixed instances policy lets an ASG combine On-Demand and Spot across several instance types. Keep a small On-Demand base, spread Spot across types and AZs, and make the app handle the two-minute interruption notice.

   AdvancedQuick answer1 min read