Syllaro Academy

AWS Certified CloudOps Engineer - Associate

Route 53 Health Checks and DNS Failover

How Route 53 decides an endpoint is healthy, why alias records use Evaluate Target Health instead of a health check, and how failover routing and zonal shift move traffic away from a failure the load balancer cannot see.

Intermediate 26 minutes 5 Learning Objectives
  1. Explain how Route 53 aggregates its global health checkers into a single healthy or unhealthy verdict
  2. Choose between an endpoint, calculated, and CloudWatch alarm health check for a given resource
  3. Configure active-passive and active-active failover, and explain when to use Evaluate Target Health instead of a health check
  4. Predict the effect of inverting or disabling a health check
  5. Use zonal shift to move traffic away from an impaired Availability Zone