Interview Q&A / AWS & Cloud

1. What is the difference between an AWS Region and an Availability Zone?

   A Region is a separate geographic area, like Mumbai, with its own set of data centres. An Availability Zone is one or more isolated data centres inside a Region, with its own power and networking. You spread an app across AZs to survive a data-centre failure, and across Regions to survive a whole-area outage or to be closer to users.

   BeginnerIn-depth3 min read
2. 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
3. What is the difference between RDS Multi-AZ and a read replica?

   Multi-AZ keeps a synchronous standby copy in another AZ for automatic failover, improving availability. A read replica is an asynchronous copy that serves read traffic to scale performance and can be promoted if needed.

   BeginnerQuick answer1 min read