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Route 53 health checks and failover routing: DOP-C02 study notes and practice questions

What to know about Route 53 health checks and failover routing for the DOP-C02 exam, from the Resilient Cloud Solutions domain (15% of the exam guide), then 1 free question to test it. Part of the DOP-C02 study guide.

Last verified against current AWS documentation ·How we write our questions

What to know for the exam

These questions ask how to send users to a healthy endpoint automatically, or move traffic between Regions on purpose.

Routing policies

Policy Fits
Failover Active-passive: answer with the secondary only when the primary’s health check fails; return to primary when it recovers
Weighted Split traffic by percentage, such as a gradual Region migration or blue/green
Latency Send users to the Region with lowest latency
Geolocation / geoproximity Route by user location (compliance, localization) or by distance with bias
Multivalue answer Return several healthy IPs
IP-based Route by client CIDR

Policies can be nested, such as latency between Regions with failover inside each.

Health checks

  • Endpoint checks (HTTP, HTTPS, TCP) from global checkers; set the path, interval, failure threshold and string matching.
  • Calculated health checks combine others with AND or OR logic.
  • CloudWatch alarm health checks monitor private resources or business metrics.
  • Checkers need inbound access through security groups to the endpoint.
  • Alias records to ELB, CloudFront and others can evaluate target health with no separate check.

Controlled failover

  • Amazon Application Recovery Controller (ARC) gives routing controls (highly available on/off switches) and readiness checks; zonal shift moves traffic away from an impaired AZ.
  • Region switch in ARC orchestrates multi-Region failover plans.
  • Lower TTLs speed up client changes.

Common traps

  • Weighted routing for automatic failover. Use failover routing with health checks.
  • Health checks blocked by security groups.
  • Changing records by hand during an outage.
  • Long TTLs on failover records, so clients keep the dead endpoint for hours.

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Question 1

Medium ·Link to this question (question 1)

A video streaming service serves its web application from an Application Load Balancer in us-east-1. A static fallback site, which shows an outage banner, runs in a second Region behind its own load balancer.

When the primary load balancer becomes unhealthy, customers should reach the fallback site within a few minutes, without any operator action. When the primary recovers, customers should return to it automatically.

The team wants the DNS record that customers use to stay the same, and it wants health checks to decide where traffic goes.

Which configuration meets these requirements?

Choose one answer.

  1. A. Create a Route 53 failover routing policy with a health check on the primary endpoint, a primary alias record, and a secondary alias record for the fallback load balancer.
  2. B. Create a weighted routing policy with a 50 percent weight on each load balancer, so that half of all requests reach the fallback site during normal operation.
  3. C. Create a latency-based routing policy for the two load balancers, and let Route 53 choose the Region that is closest to each customer.
  4. D. Keep a single record that points to the primary, and have an operator run a script to change the record to the fallback site after the outage is confirmed by the on-call engineer.
Show the answer and explanation

Answer: A

  • A. Right: Correct. With failover routing, Route 53 answers with the secondary record only when the primary's health check fails, and it returns to the primary when that check passes. The customer-facing name stays the same. Learn more: Configuring DNS failover (opens in a new tab)
  • B. Wrong: Weighted records send traffic to both sites all the time, which the streaming service does not want. A weighted policy does not switch all traffic away from a failed endpoint based on health. Learn more: Values that you specify when you create or update health checks (opens in a new tab)
  • C. Wrong: Latency routing picks the closest Region, not the healthy one, so customers could still be sent to the failed primary. It does not provide the fallback behavior the team described.
  • D. Wrong: This depends on an operator being available and fast enough for a few-minute target. It also gives no automatic return to the primary when it recovers.

Explanation

Route 53 failover routing answers with the secondary record only when the primary's health check fails, and it returns to the primary when the check recovers. The record name stays the same for customers. Weighted and latency policies do not switch by health, and a manual script depends on an operator.

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